​As we enter the 2020s, the backdrop of the climate crisis remains grim. Recent scientific reports tell us that global greenhouse gas emissions are increasing, not declining as they need to. Emissions increased by 1.5% in 2017, 2% in 2018 and are anticipated to increase by 0.6% in 2019.[i]  While emissions are decreasing too slowly in industrialized countries, they are increasing all too quickly in large developing countries. Despite this increase, per capita emissions in the United States and Europe remain 5-20-fold higher than in China and India,[ii] and a significant number of emissions in developing countries are attributable to the manufacture and production of goods consumed in developed countries.

The window to achieve the Paris Agreement’s goals of limiting mean global temperature increases to well below 2°C above pre-industrial averages, and the aspirational goal of a 1.5°C limited increase, is closing quickly. Scientists are increasingly warning of the catastrophic threats of climate change.[iii] Lack of progress by the world’s governments places vulnerable countries such as small island developing states, as well as vulnerable communities within developing and developed countries, at increased risk.[iv] As the United States recently submitted its official notice to withdraw from the Paris Agreement, questions have been raised about the structural integrity of the agreement, and whether it can withstand these countervailing pressures.

In early nineteenth century Australia, surveyors were given a near impossible task by colonial authorities. They were asked to use their expeditions to ascertain "the general nature of the climate, as to heat, cold, moisture, winds, rains, periodical seasons." [1] Meeting this directive was difficult because most surveyors did not spend more than a few days or weeks in a location that was otherwise unfamiliar to them. In these situations, precision instruments such as thermometers and barometers were of limited utility as they could only offer a reading at the time of visitation and not for any other time of year or for any other year when atmospheric conditions might be quite different.
 
Plants provided one solution to the dilemma.
 
In the opening decades of the nineteenth century, Aboriginal Australians helped surveyors to decipher some of the relationships between plants and atmosphere in Australia. This article shows how surveyors were taught that the distribution of certain tree species could help them understand the way rainfall patterns varied over space. It also shows how surveyors learnt to use the watermarks on trees and debris lodged in branches as indications of the way rainfall patterns varied over time. With the help of Aboriginal Australians, surveyors were practicing a sort of historical climatology. They were attempting to understand past atmospheric changes in a given area using indirect sources. Can the evidence contained in surveyors’ journals and maps help the historical climatologists and climate scientists of today? This article argues that they can.
 
When Thomas Mitchell, the surveyor-general of New South Wales, was tasked with charting the two major inland river systems of Australia’s south east, his Wiradjuri guides helped him understand the association of particular plants with particular atmospheric and hydraulic conditions. Mitchell was taught that the yarra tree (known today as the river red-gum or eucalyptus camaldulensis) indicated the presence of a river or lake. Mitchell scanned the horizon for these tall trees when he wanted to locate a place of permanent waters:

​Mitchell’s Wiradjuri guides showed him that the presence of goborro trees, by contrast, indicated a place of transient waters. Mitchell learnt that the goborro tree (most likely the plant known today as black box or Eucalyptus largiflorens) flourished on plains subject to temporary inundations rather than on the banks of more permanent waters. “These peculiarities,” Mitchell wrote, “we ascertained only after examining many a hopeless hollow where the goborro grew by itself; nor [sic] until I had found my sable guides eagerly scanning the yarra from afar when in search of water, and condemning any distant view of goborro trees as hopeless during that dry season.” [3] But the presence of particular trees did more than give surveyors an indication of how rain fell and flowed over space in inland Australia.
 
Flood marks on trees such as the yarra also gave surveyors an indication of how much rainfall an area had received in the past. Some of Mitchell’s travels around Australia’s inland river systems were during the drier than average year of 1835, which meant that he did not see how the country looked when it was well-watered. [4] But Mitchell often used the water stains on river red gums and other trees to make judgements about the rainfall variability of an area. Near the inland Lachlan River, for example, he noticed “a tract extending southward from the river for about three miles, on which grew yarra trees bearing the marks of occasional floods to the height of a foot above the common surface.” [5]

Other surveyors working in Australia such as John Oxley and Charles Sturt also used the flood marks left on trees to understand the rainfall variability that a region could experience. Travelling through inland New South Wales northwest of Sydney in 1818, Oxley did not think that the Castlereagh River had been flooded for a long period because there were “no marks of wreck or rubbish on the trees or banks” of the river. [6] Cedar trees along the Hastings River further east, by contrast, bore “marks of flood exceeding twenty feet, but confined to the bed of the river.” [7] Travelling southwest of Sydney about ten years later, Charles Sturt reported “marks of recent flood on the trees, to the height of seven feet.” [8]
 
Surveyors’ atmospheric observations were not, moreover, confined to their journals. They were also written on their maps of Australia. Sometimes, this data was indirectly transcribed and would only be decipherable when read together with the surveyors’ written accounts. Take the example of an 1826 map of New South Wales, which was based on the work of two surveyors. In addition to the names of settlements, rivers and mountains, the map had descriptions of prevailing plant life written on to its surface. [9] The presence of plants such as “box” (or goborro as Mitchell called it) on the map indicated that an area was subject to flood as this was the plant that liked to wet its feet in temporary inundations.
 
More often, the atmospheric information plants provided was directly recorded on to surveyors’ maps. In 1822, for instance, Oxley produced a map which included the Lachlan River, a waterway he had visited five years earlier in 1817. By the sides of the River, Oxley wrote over the map “Low Marshy Country devoid of Hills and occasionally overflowed, perhaps to the extent of 30 miles on each side of the River.” Near other rivers on the map, Oxley also added earth-atmosphere descriptions such as “marks of the flood 30 feet above the present surface of the River’ and ‘Marks of the rise of the flood about 16 feet.” [10] Surveyors’ maps were, then, not just topographical representations of the country – they were also atmospheric representations.
 
The atmospheric information contained in these maps and journals has been overlooked by historians and historical climatologists. This is in part because the maps and journals were created in a period when the use of precision instruments such as thermometers was becoming increasingly widespread and when methods for observing these instruments were being standardised. But as this article (and my doctorate research) shows, instruments were not always the preferred newcomer method for accessing information about the atmosphere. Whereas instruments offered surveyors isolated snapshots of the atmosphere, plants revealed annual and interannual trends. Like historical climatologists and paleoclimatologists today, nineteenth century surveyors yearned to know the atmospheric history of a place.
 
This Australian case study suggests that there are at least three reasons why survey maps and journals deserve the attention of contemporary climate scientists. First, these sources could help historical climatologists overcome the bias toward reconstructing past temperatures over other atmospheric variables. “Most of the climate reconstructions over say the last 1000 years,” Brázdil et al. argued in 2005, "focus on temperature." [11] More recently, the editors of the 2018 Palgrave Handbook of Climate History have argued that precipitation is a "field of research calling for more effort by climate historians." [12] One of the reasons that past precipitation patterns have received less attention than past temperature patterns is because the latter tend to be better represented in the sources. Survey journals and maps can help address this bias in the sources.
 
Second, these sources not only offer information on an under-represented atmospheric variable. They also offer information on under-represented regions. Often, when nineteenth century rain-gauge measurements were taken, they were recorded in urban centers and port cities. This is a problem because precipitation rates and patterns are “highly localized” phenomena. [13] The amount of rainfall one area received could be different for an area just a few kilometers away. Attaining more geographically dispersed precipitation information is therefore crucial to producing more accurate and geographically diverse reconstructions. Surveyors’ records offer information about precipitation patterns for areas where no rain-gauge records were kept in nineteenth-century Australia.

​Finally, survey maps and journals could provide scientists with information about how particular plants are responding to the earth’s changing atmosphere. The river red gums that are frequently mentioned in Mitchell’s journals have been the subject of recent research into the water needs of flood-plain trees. These trees, researchers have shown, are crucial to the health of flood-plain eco-systems: ‘Everything relies on the red gum to maintain health’. [14] Yet while it is well known that river red gums have adapted strategies for surviving long periods of drought, exactly how long these trees can go without water is less certain. Dr. Tanya Doody’s research, for example, indicates that in conditions of below average rainfall, the trees should not go more than seven years without being flooded. [15] The records of surveyors could offer an additional source of data for such important research projects.
 
In the case of Australia, survey maps and journals are accessible sources. The journals referred to in this article are all digitized and available online without the need for payment or institutional affiliation. Public institutions such as the National Library of Australia and the State Library of New South Wales have also digitized numerous survey maps in high resolution, which allows researchers to zoom in on the atmospheric details that surveyors marked on their charts. Recognizing the valuable atmospheric data contained in these historical sources could prompt other institutions to digitize more survey journals and maps. Such a project promises to help climate scientists in their quest to reconstruct past climates in order to better understand future atmospheric changes and the effects of those changes on plant life and river systems. It also promises to illuminate the way past efforts to understand the atmospheric patterns in Australia were sometimes joint newcomer-Indigenous endeavors. 

Memory is one of the most powerful parts of the human psyche. It can help us make sense of the world around us, but it can also cloud our vision. Over long timeframes, memory can actually become embedded into a culture in ways that are difficult to comprehend. One of the complex effects of this sort of cultural memory may be the development of a culture of resilience in the face of extreme climatic events. Long-term environmental memories might help a community respond to otherwise destructive climate changes in a way that allows them to survive, recover, and sometimes even thrive. Given the increasing impact of extreme weather events due to anthropogenic climate change, it is uniquely important right now to understand how memory can contribute to creating a more resilient culture.

In order to make sense of the connections between memory, culture, and climate, this article considers how memory might have played a role in the interpretation of extreme weather events in Qing dynasty China (1644–1912). A look at Qing dynasty records suggests that long-term environmental memory could indeed help cultivate a culture of resiliency, while at the same time skewing how accurate the perception of a disaster is. More than anything, this look into the potential roles of memory provides a new perspective with which to think about our current interpretation of environmental changes and cultural capacity for adaptation.

Researchers generally agree that we actively use our memory when processing our surroundings, including weather.[1] Imagine you live in a town that has faced extreme flooding in recent years. When you experience a heavy rain, you will probably remember the floods. However, the exact way that we use memory to interpret the environment may not be so simple as providing the background with which we think about weather or climate change. In her work on biological control programs, scholar Karen Middleton describes a feedback loop by which present events reshape how the past is remembered at the same time as the interpretation of past events shapes the understanding of present conditions.[2] So just as memories of a disastrous flood would affect how villagers interpret a heavy rain in their present, if they are not currently experiencing flooding it could influence their memories of that past disaster. In our hypothetical water-logged village, perhaps the current rains are locally just as strong as the rains during a past flood. Yet because those rains are not accompanied by a flood, villagers might mistakenly remember the first flood as having more extreme rains.

There is also some evidence that memory can contribute to long-term integration of climate awareness into human societies. Archaeologist Toby Pillat has offered the idea that daily interactions with weather can create cultural norms that dictate how future people might interact with their climate.[3] The cultural norms that Pillat refers to may even develop into a culture of resiliency, as described by environmental historian Adam Sundberg in his work on the infamous Christmas Flood of 1717. Sundberg describes a process of “disaster-induced learning,” in which repeated incidents of disaster lead to long-term “cultures of coping,” a gradualist theory that he reports as currently trending in the field of disaster history.[4]

Occasionally, this sort of cultural learning about climate may take the form of a clearer understanding of weather events over time. For example, environmental historian Dagomar Degroot found that “the human consequences of the Little Ice Age…prompted Dutch citizens to think comparatively and accurately about weather across long timeframes.”[5] Yet long-term environmental learning may also lead to a skewed perception of climatic events due to increased societal preparedness. In his study of lower Austrian floods in 1572-3, scholar Christian Rohr makes the argument that “due to the preparedness of the population, most of the floods were not perceived as disasters.”[6] While in some cases, memory might lead to more accurate interpretations of climate, in others its concrete effects in establishing adaptive cultures may have the opposite impact – which in turn could influence the long-term understanding of climate in a society.

So how might memory have played a role in Qing dynasty cultural understandings of, and responses to, climate change? To answer this question, we will look at the North China Plain (NCP). The NCP is defined here as the modern-day provinces of Beijing, Tianjin, Hebei, Shandong, Henan, Anhui, and Jiangsu. Such a wide definition of the area is useful in that it allows for more data, and therefore clearer identification of patterns; it is reasonable, in that precipitation extremes across the NCP are fairly standard.
 
The Qing dynasty was not only a time of distinct dynastic change in China, but it was also a part of an era of occasionally global climate change that is often termed the Little Ice Age (LIA). The LIA is generally understood to be a period of cooling that in many places reached its coldest phase between the fifteenth and eighteenth centuries.[7] While there was a broad global trend of cooling, the LIA had different effects across different areas over variable time scales. In China, the LIA can be split into three stages: a cool, dry early period, a warm, dry middle period, and a wet, cold late period.[8] These changes are thought to be related to changes in both East Asian Summer Monsoons (EASM), and the El Niño-Southern Oscillation (ENSO) cycle. [9] The NCP in particular experiences highly variable precipitation patterns due to the strong effect of the EASM in the region. [10] Across the Qing dynasty, the region suffered many environmental disasters, including extreme floods and droughts.

During the Qing dynasty, gazetteers called fangzhi 方志 were systematically written every day. Official chronicles were mandated by the government; many more local gazetteers were kept by various scholars or officials, and organized by government historians over the course of the Qing dynasty. These primary source texts contain detailed information about the weather. Because they were written systematically, whether or not a chronicle mentions a disaster, like the floods and droughts we will examine here, is more likely to be a result of the recorder’s interpretation of the weather than, for example, the recorder’s desire or freedom to write. Therefore, a comparison of how often a disaster was documented with the actual occurrence of extreme events can be used as a way to guess at the role of memory and culture in the interpretation of weather. The recently published Reconstructed East Asian Climate Historical Encoded Series (REACHES) database uses the fangzhi to create data points that represent weather events, allowing us to build a timeline for how often a drought or flood disaster was recorded throughout the Qing dynasty.

In order to create a timeline for when droughts and floods actually occurred during the Qing dynasty in the NCP, we can look at the reconstruction of extreme weather events from the work of a team of Chinese geographers led by Zheng Jingyun. Zheng and his co-authors have used a wide range of primary text sources, then verified the information in them with weather measurements compiled using scientific instruments. They also used statistical analysis to account for the fact that the number of textual sources increases over time, due to the higher likelihood that more recent records could be preserved. While it would be ideal to have more scientific data to create our timeline, such as information from tree rings or pollen records, the reality is that most climate history for this region and time relies on historic archives, probably due to the abundance of primary source texts from China.

The methods used by Zheng and his team make their results some of the best currently available, and most useful for this comparison. They look specifically at extreme droughts and floods, which they define as periods lasting more than three years that have an amount of rain more than one and half times greater or lower than about the average precipitation level. The fact that they look at both severity and time scale means that when they note the occurrence of disaster, there should theoretically be fangzhi records for that disaster from across the NCP.

Building these parallel timelines of documentation and occurrence for both droughts and floods reveals curious correlations and discrepancies. First, the highest numbers of fangzhi records of flood and drought do not always correlate with the frequency and severity of disasters. For example, two of the most extreme events identified by Zheng and his co-authors in the NCP were a decade-long drought that took place from 1634 to 1644, and another calamitous drought from 1719 to 1723.[11] Yet there are several points in our timeline of documentation where the amount of drought records is higher than in those years of especially extreme drought. While the frequency of fangzhi flood documentation lines up a little bit better with the occurrence of extreme floods, there are still moments where we see a higher amount of flood records in years when extreme flooding did not occur.

Disaster records therefore often did not grow more common during, or even immediately after, many of the worst disasters. Usually the quantity of fangzhi records only surged over a decade after a disaster. In fact, years immediately following extreme weather events generally had fewer records of disaster. These patterns may suggest that when a disaster was ongoing, it was harder to keep records like local fangzhi as people struggled to survive and rebuild. They could also indicate that in the short term, the memory of a disaster helped give a more realistic sense of what constituted that sort of event, and led to more accurate reporting. However, over time, this accuracy of memory may have faded, and instead cultural memory could have encouraged a heightened sensitivity towards recording disaster.

Looking more broadly, it seems that there is overall more documentation of disaster earlier in Qing history. For both droughts and floods, moving forward in time there is a moderate trend from more to fewer fangzhi records of either type of extreme event. Moreover, the amount of variation in disaster documentation frequency from year to year appears to be higher earlier in history. There also seems to be a slight trend over time towards more stability in the amount of records of both floods and droughts.

These wide patterns of decreasing records and increasing stability of documentation frequency may suggest more or less long-term accuracy in memory of disaster severity, depending on whether you emphasize periods of extreme events or of non-disaster. This might also point to the development of a culture of resiliency. If the people of the NCP were better equipped to deal with these types of events over time, they might not be so inclined to interpret the weather as a disaster, even in cases when it was as extreme as in previous decades.

It is clear that there is no simple relationship between memory and environmental disasters. It should also be noted that these potential patterns and connections are based on a simple visual comparison of timelines. However, the lack of precision here speaks to the fact that this area holds much potential for future research. In particular, Chinese climate history scholarship thus far has often focused on using statistical significance testing to propose correlative relationships between environmental changes and societal reactions. [12] This sort of quantitative research is an ideal starting point for exploring more nuanced aspects of environmental history. It allows for engagement with unique scholarship, like the ideas about memory explored here, and in this case, offers diverse new perspectives on the possible links between culture and environmental extremes.

This study reveals that memory could be a powerful part of how we respond to environmental changes. At the same time as memory may help develop an adaptive culture, accurate judgement of the seriousness of a disaster might be clouded. As we enter an era of increased extreme weather events, it is important to consider whether our interpretations of disaster are accurate. Moreover, while long-term memory has potentially contributed to climate change resilience in our cultures, our current adaptations may not be enough to deal with the disasters of the future. We might also examine how the gradual nature of the current rise in disaster severity may influence both our cultural adaptations and misunderstandings of memory. As the consequences of anthropogenic climate change become more pronounced, it is crucial that we look to the past for new ideas about the relationship between culture and environment, including the complex effects of memory.

Works Cited:
 
Andrew Salvador Mathews. "Suppressing Fire and Memory: Environmental Degradation and Political Restoration in the Sierra Juárez of Oaxaca, 1887-2001." Environmental History  8:1 (2003): 77-108.
 
Brook, Timothy. The Troubled Empire: China in the Yuan and Ming Dynasties. Cambridge, USA: Harvard University Press, 2010.
 
Cui, Anning, Chunmei Ma, Lin Zhao, Lingyu Tang, and Yulian Jia. "Pollen Records of the Little Ice Age Humidity Flip in the Middle Yangtze River Catchment." Quaternary Science Reviews 193 (2018): 43-53.     
 
Degroot, Dagomar. “Climate Change and Society from the Fifteenth Through the Eighteenth       Centuries.” WIREs Climate Change Advanced Review, 2018.
 
Degroot, Dagomar. The Frigid Golden Age: Climate Change, the Little Ice Age, and the Dutch  Republic, 1560–1720. New York: Cambridge University Press, 2018.    
 
Fang, XiuQi, Xiao, LingBo, and Wei, ZhuDeng. “Social Impacts of the Climatic Shift Around   the Turn of the 19th Century on the North China Plain.” Science China Earth Sciences 56:6 (2013): 1044–58.
 
Forgas, Joseph P., Liz Goldenberg, and Christian Unkelbach. 2009. Can Bad Weather Improve        Your Memory? an Unobtrusive Field Study of Natural Mood Effects on Real-Life    Memory. Vol. 45.
 
Guy, R. Kent. Qing Governors and Their Provinces: the Evolution of Territorial Administration in China, 1644-1796. Seattle: University of Washington Press, 2010.
 
Hall, A. and G. Endfield, “Snow Scenes”: Exploring the Role of Memory and Place in    Commemorating Extreme Winters. Wea. Climate Soc. 8 (2016): 5–19.
 
Hao, Zhixin, Yingzhuo Yu, Quansheng Ge, and Jingyun Zheng. “Reconstruction of High            resolution Climate Data over China from Rainfall and Snowfall Records in the Qing Dynasty.” WIREs: Climate Change 9 (3) (2018): e517.
 
Koselleck, Reinhart. Futures Past: On the Semantics of Historical Time. Cambridge, Mass: MIT      Press, 1985.
 
Kwiatkowski, Teresa, and Alan Holland. "Dark Is the World to Thee: A Historical Perspective      on Environmental Forewarnings." Environment and History 16:4 (2010): 455-82.        
 
Li, S., He, F. & Zhang, X., "A spatially explicit reconstruction of cropland cover in China from 1661 to 1996." Reg Environ Change 16:2 (2016): 417-428.
 
Middleton, Karen. "Renarrating a Biological Invasion: Historical Memory, Local Communities    and Ecologists." Environment and History 18:1 (2012): 61-95.        
 
Pillatt, Toby. “Experiencing Climate: Finding Weather in Eighteenth Century Cumbria.” Journal      of Archaeological Method and Theory 19:4 (December 2012): 564–81.        
 
Rohr, Christian. "Floods of the Upper Danube River and Its Tributaries and Their Impact on        Urban Economies (c. 1350-1600): The Examples of the Towns of Krems/Stein and Wels            (Austria)." Environment and History 19:2 (2013): 133-48.        
 
Rohr, Christian. "Man and Natural Disaster in the Late Middle Ages: The Earthquake in            Carinthia and Northern Italy on 25 January 1348 and Its Perception." Environment and            History 9:2 (2003): 127-49.
 
Shuoben Bi, Shengjie Bi, Changchun Chen, Athanase Nkunzimana, Yanping Li, and Weiting           Wu. “Spatial Characteristics Analysis of Drought Disasters in North China during         the Ming and Qing Dynasties.” Natural Hazards & Earth System Sciences Discussions 2016, 1–13. 
 
Sundberg, Adam. “Claiming the Past: History, Memory, and Innovation Following the  Christmas Flood of 1717.” Environmental History 20:2 (April 2015): 238–61.       
 
Wang, P. K. et al. Construction of the REACHES climate database based on historical         documents of China. Sci. Data. 5:180288.
 
Zheng, J., W. C. Wang, Q. Ge, Z. Man, and P. Zhang, 2006: Precipitation variability and extreme    events in eastern China during the past 1500 years. Terr. Atmos. Ocean. Sci., 17, 579-  592.

On May 11, birders in 130 countries took part in World Migratory Bird Day (WMBD). This citizen science and conservation project enrolls professional and amateur ornithologists twice a year—in May and October—to record sightings of hundreds of species during their spring and fall passages through continental and hemispheric regions, or so-called flyways, across Africa, Europe, Asia, the Americas, and Australasia.
 
WMBD was first organized in 2006 only in part as a way to recruit people to collect more data points. Its purpose is also to convey the urgency of the climate crisis for migratory animals by publicizing how profoundly avian populations, the geography of their flyways, and the timing of their movements have been affected by a host of modern ecological pressures resulting from human activity, including climate change. (Every year WMBD focuses on a different threat, which, for the second annual event in 2007, was “Migratory Birds in a Changing Climate.”) [1]
 
What’s sometimes lost in such initiatives, however, is their considerable history. As I’m discovering in one of my current research projects called “Flight Paths for Birds and other Migrants,” which focuses on theories of migration developed in the 17th and 18th centuries, many of the questions that inform activities like WMBD—even questions about anthropogenic forces—emerged much, much earlier than is usually acknowledged. Participants in WMBD continue a very long line of bird observers who have generated crowd-sourced data to learn more about the behavior of migratory species. Collectively, this constitutes a global, however uneven, record of avian, insect, and other animal movements amassed over centuries.
 
The ancient reliance on birds for a variety of cultural, spiritual, and utilitarian purposes all over the world, informed indigenous knowledge about where and when some itinerant species would normally arrive in a particular place. The earliest avowedly scientific attempts to grasp the geographical and temporal scale of these cyclical movements—including the possible effect of weather and climate on them—date to at least the late 17th century, when individuals increasingly began to keep records of arrival and departure dates. Most historians of ornithology as an empirical science focus on the Victorian period after the development of evolutionary biology, but pre-Darwinian ideas about avian migration recognized, albeit implicitly and without the statistical precision, that 60% of species are migratory (and that many or most other birds may have been migratory millennia ago).
 
Early naturalists, from Cotton Mather to Gilbert White and John James Audubon, were fascinated by what they called ‘birds of passage,’ especially the capacity to dwell in a range of aquatic, aerial, and terrestrial environments and to regularly relocate between different hemispheres in groups. And their attention to these peculiar traits also spurred them to speculate about migratory birds’ susceptibility to change, including changes in their seasonal habitats caused by human societies, such as colonization, the expansion of farmland, and the growth of towns.
 
Their early documents could provide both temporal depth and unique insights into the natural history of climate and migration, particularly for conservationists interested in adaptations to environmental changes in the 20th and 21st centuries. This is especially so because many aspects of migratory patterns—their origins, geography, seasonality, and changes over time—have remained mysterious to scientists, even now.

When the biologist Frederick Lincoln coined the term flyway in 1935, he meant it to describe migratory birds’ “ancestral routes”—what were then thought to be the typical extent of the vast ranges and diverse environments they inhabited during different times of the year. Specifying the geography of these migratory corridors would, in turn, assist in ambitious banding projects and the creation of wildlife refuges. [2] Since then, increasingly sophisticated surveillance technologies have been developed to understand how much the boundaries of flyways and periodicity of biannual movements may have actually shifted over time, both in the deep evolutionary past as well as in the present.
 
Yet if it’s clear that rising temperatures, coastal erosion, light and air pollution, urbanization, deforestation, and predation affect migratory bird populations, like much else about our knowledge of their biology, it remains unclear exactly how or how permanently ongoing climate change might shift particular species’ range boundaries, breeding or feeding grounds, and arrival or departure dates.
 
To take just one of numerous examples, in 2010 ecologists in the Netherlands relying on 20 years of trend data gathered by “many thousands of volunteer birdwatchers across Europe” found strong evidence predicting that the continuation of earlier spring thaws and a longer season of heat waves on the continent will likely make climate change an underlying cause of population decline among long-distance migrants like pied flycatchers. Yet five years later, another study with similar parameters and common co-authors concluded that such predictions were less reliable than they’d hoped. “Contrary to expectations,” the patterns they observed between 2004 and 2014 were inconsistent with those from the 1984-2004, leading to equivocal results. [3] It’s not only that as research proceeds some findings about the relationship between climate change and avian migration appear contradictory; it is also that, especially as the current climate crisis grows, the dynamic differs significantly by species, region, and time frame.
 
The history of ornithology can’t help to absolutely resolve these variances: the science of animal migration—like all scientific knowledge—will necessarily be susceptible to revision. But studying historical sources could encourage conservationists to recognize that anthropogenic climate change is only the most recent, if perhaps the most drastic, example of how the lives of non-human animals have long been observed and shaped, for better or worse, by people.

Anya Zilberstein is associate professor of history at Concordia University. She is the author of A Temperate Empire: Making Climate Change in Early America (Oxford University Press, 2016), and she is currently working on a new project, "Fodder for Empire: Feeding People Like Other Animals," which examines the history of experiments in producing and distributing non-perishable, high-calorie, low-cost food for animals and people in the British Empire.

People displaced by extreme weather events and slower-developing environmental disasters are often called “climate refugees,” a term popularized by journalists and humanitarian advocates over the past decade. The term “refugee,” however, has a very precise meaning in US and international law and that definition limits those who can be admitted as refugees and asylees. Calling someone a “refugee” does not mean that they will be legally recognized as such and offered humanitarian protection.
​
The principal instruments of international refugee law are the 1951 United Nations Convention Relating to the Status of Refugees and its 1967 Protocol, which defined a refugee as:

"any person who owing to well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality and is unable, or owing to such fear, is unwilling to avail himself of the protection of that country; or who, not having a nationality and being outside the country of his former habitual residence as a result of such events, is unable or, owing to such fear, is unwilling to return to it." [i]

This definition, on which current U.S. law is based, does not include any reference to the “environment,” “climate,” or “natural disaster,” that might allow consideration of those displaced by extreme weather events and/or climate change.

In some regions of the world, other legal instruments have supplemented the U.N. Refugee Convention and Protocol, and these instruments offer more expansive definitions of refugee status that might offer protections to the environmentally displaced. The Organization of African Unity’s “Convention Governing the Specific Aspects of Refugee Problems in Africa (1969)” includes not only external aggression, occupation, and foreign domination as the motivating factors for seeking refuge, but also “events seriously disturbing the public order.”[ii]  In the Americas, the non-binding Cartagena Declaration on Refugees (1984), crafted in response to the wars in Central America, set regional standards for providing assistance not just for those displaced by civil and political unrest but also those fleeing “circumstances which have seriously disturbed the public order.”[iii] The Organization of American States has also passed a series of resolutions offering member states additional guidance on how to respond to refugees, asylum seekers, stateless persons, and others in need of temporary or permanent protection. In Europe, the European Union Council Directive (2004) has identified the minimum standards for the qualification and status of refugees or those who might need “subsidiary protection.”[iv]

Together, these regional and international conventions, protocols, and guidelines acknowledge that people are displaced for a wide range of reasons and that they deserve respect and compassion and, at the bare minimum, temporary accommodation. Climate change has been absent in these discussions perhaps because environmental disruptions such as hurricanes, earthquakes, and drought were long assumed to be part of the “natural” order of life, unlike war and civil unrest, which are considered extraordinary, man-made, and thus avoidable. The expanding awareness that societies are accelerating climate change to life-threatening levels requires that countries reevaluate the populations they prioritize for assistance, and adjust their immigration, refugee, and asylum policies accordingly.

If nuclear power is to be used as a stop-gap or transitional technology for the de-carbonization of industrial economies, what comes next? Energy history could offer new ways of imagining different energy futures. Current scholarship, unfortunately, mostly offers linear narratives of growth toward the development of high-energy economies, leaving little room to imagine low-energy futures. As a result, energy historians have rarely presented plausible ideas for low-energy futures and instead dwell on apocalyptic visions of poverty and the loss of precious, ill-defined “standards of living.”

The fossil fuel-based energy systems that wealthy, industrialized nation states developed in the nineteenth and twentieth centuries now threaten the habitability of the Earth for all people. Global warming lies at the heart of the debate over future energy transitions. While Nancy Langston makes a strong case for thinking about the use of nuclear power as a tool for addressing the immediate emergency of carbon pollution of the atmosphere, her arguments left me wondering what energy futures will look like after de-carbonization. Will industrialized economies continue with unconstrained growth in energy consumption, expand reliance on nuclear power, and press forward with new technological innovations to consume even more energy (Thorium reactors? Fusion reactors? Dilithium crystals?)? Or will profligate energy consumers finally lift their heads up from an empty trough and start to think about ways of living with less energy? Unfortunately, energy history has not been helpful in imagining low-energy possibilities.

For the past couple of years, I’ve been getting familiar with the field of energy history and, for the most part, it has been the story of more. [1] Energy history is a related field to environmental history, but also incorporates economic history, the history of capitalism, social history, cultural history and gender history (and probably more than that). My particular interest is in the history of hydrocarbons, but I’ve tried to take a wide view of the field and consider scholarship that examines energy history in deeper historical contexts.

There are several scholars who have written such books that consider the history of human energy use in deep time. For example, in 1982, Rolf Peter Sieferle started his long view of energy history in The Subterranean Forest: Energy Systems and the Industrial Revolution by considering Paleolithic societies. Alfred Crosby’s Children of the Sun: A History of Humanity’s Unappeasable Appetite for Energy (2006) begins its survey of human energy history with the advent of anthropogenic fire and its use in cooking. Vaclav Smil goes back to so-called “pre-history” at the start of Energy and Civilization: A History (2017) to consider the origins of crop cultivation. 

In each of these surveys energy historians track the general trend of growing energy use. While they show some dips in consumption and global regional variation, the story they tell is precisely as Crosby puts it in his subtitle, a tale of humanity’s unappeasable appetite for greater and greater quantities of energy. 

The narrative of energy history in the scholarship is remarkably linear, verging on Malthusian. According to Smil: 

“Civilization’s advances can be seen as a quest for higher energy use required to produce increased food harvests, to mobilize a greater output and variety of materials, to produce more, and more diverse, goods, to enable higher mobility, and to create access to a virtually unlimited amount of information. These accomplishments have resulted in larger populations organized with greater social complexity into nation-states and supranational collectives, and enjoying a higher quality of life.” [2]

Indeed, from a statistical point of view, it’s difficult not to reach the conclusion that humans have proceeded inexorably from one technological innovation to another, finding more ways of wrenching power from the Sun and Earth. The only interruptions along humanity’s path to high-energy civilization were war, famine, economic crisis, and environmental collapse. 

Canada’s relatively short energy history appears to tell a similar story. As Richard W. Unger wrote in The Otter~la loutre recently, “Canadians are among the greatest consumers of energy per person in the world.” And the history of energy consumption in Canada since Confederation shows steady growth and sudden acceleration with the advent of mass hydrocarbon consumption between the 1950s and 1970s. Steve Penfold’s analysis of Canadian liquid petroleum use focuses on this period of extraordinary, nearly uninterrupted growth in energy consumption. Only in 1979 did Canadian petroleum consumption momentarily dip in response to an economic recession. “What could have been an energy reckoning…” Penfold writes, “ultimately confirmed the long history of rising demand.” [2]
​
I’ve seen much of what Penfold finds in my own research on the history of oil pipeline development in Canada. Take, for instance, the Interprovincial pipeline system, Canada’s largest oil delivery system. For much of Canada’s “Great Acceleration” the history of more couldn’t be clearer:

This view of energy history as the history of more informs some of the conclusions (and predictions) of energy historians. Crosby is, perhaps, the most optimistic about the potential of technological innovation to resolve what he describes as humanity’s unsustainable use of fossil fuels. In Crosby’s view, “the nuclear reactor waits at our elbow like a superb butler.” [4] For the most part, he is dismissive of energy conservation or radical reductions in energy consumption as alternatives to modern energy systems, which he admits are “new, abnormal, and unsustainable.” [5] Instead, he foresees yet another technological revolution as the pathway forward, carrying on with humanity’s seemingly endless growth in energy use.
​
Energy historians, much like historians of the Anthropocene, have a habit of generalizing humanity in their analysis of environmental change. As I wrote last year in The Otter~la loutre, “To understand the history of Canada’s Anthropocene, we must be able to explain who exactly constitutes the “anthropos.”” Energy historians might consider doing the same. The history of human energy use appears to be a story of more when human energy use is considered in an undifferentiated manner. The pace of energy consumption in Canada, for instance, might look different when considering the rich and the poor, settlers and Indigenous people, rural Canadians and urban Canadians. Globally, energy histories around the world tell different stories beyond the history of more including histories of low-energy societies and histories of energy decline. Most global energy histories focus on industrialized societies and say little about developing nations and the persistence of low-energy, subsistence economies.

If Smil is correct and “Indeed, higher energy use by itself does not guarantee anything except greater environmental burdens,” then future decisions about energy use should probably consider lower energy options. [6] Transitioning away from burning fossil fuels by using nuclear power may alleviate the immediate existential crisis of global warming, but confronting the environmental implications of high-energy societies may be the bigger challenge. To address that challenge, we may need to look back at histories of less.

Sean Kheraj is the director of the Network in Canadian History and Environment. He’s an associate professor in the Department of History at York University. His research and teaching focuses on environmental and Canadian history. He is also the host and producer of Nature’s Past, NiCHE’s audio podcast series and he blogs at http://seankheraj.com.

[1] I’m borrowing from Steve Penfold’s pointed summary of the history of gasoline consumption in Canada: “Indeed, at one level of approximation, you could reduce the entire his-tory of Canadian gasoline to a single keyword: more.” See Steve Penfold, “Petroleum Liquids” in Powering Up Canada: A History of Power, Fuel, and Energy from 1600 ed. R. W. Sandwell (Montreal: McGill-Queen’s University Press, 2016), 277.

[2] Vaclav Smil, Energy and Civilization: A History (Cambridge: MIT Press, 2017), 385.

[3] Penfold, “Petroleum Liquids,” 278.

[4] Alfred W. Crosby, Children of the Sun: A History of Humanity’s Unappeasable Appetite for Energy (New York: W.W. Norton, 2006), 126.

[5] Ibid, 164.
​
[6] Smil, Energy and Civilization, 439.

Nuclear power is back, riding on the growing fears of catastrophic climate change that lurks around the corner. The looming climate crisis has rekindled heated debate over the advantages and disadvantages of nuclear power. However, advocates and opponents alike tend to overlook or downplay a unique risk that sets atomic energy apart from all other energy sources: proliferation of nuclear weapons.
 
Despite the lasting tragedy of the 2011 Fukushima disaster, the elusive goal of nuclear safety, and the stalled progress in radioactive waste disposal, nuclear power has once again captivated the world as a low-carbon energy solution. According to the latest IPCC report, released in October 2018, most of the 89 available pathways to limiting warming to 1.5 oC above pre-industrial levels see a larger role for nuclear power in the future. The median values in global nuclear electricity generation across these scenarios increase from 10.84 to 22.64 exajoule by 2050.
 
The global nuclear industry, after many setbacks in selling its products, has jumped on the renewed interest of the climate policy community in atomic energy. The World Nuclear Association has recently launched an initiative called the Harmony Programme, which has established an ambitious goal of 25% of global electricity supplied by nuclear in 2050. Even some critics agree that nuclear power should be part of a future clean energy mix. The Union of Concerned Scientists, a U.S.-based science advocacy group and proponent of stronger nuclear regulations, recently published an op-ed urging the United States to “[k]eep safely operating nuclear plants running until they can be replaced by other low-carbon technologies.”
 
But the justified focus on energy production vis-à-vis climate change obscures the debate that until recently had defined the nuclear issue: weapons proliferation. It is often said that a global nuclear regulatory regime, grounded on the 1968 Nuclear Non-Proliferation Treaty (NPT) and the International Atomic Energy Agency (IAEA)’s safeguards system, has proven successful as a check against the diversion of fissile materials from peaceful to military uses. There is indeed a good reason for this optimism. Since 1968, only three countries (India, Pakistan, North Korea) have publicly declared possession of nuclear weapons – a far cry from “15 or 20 or 25 nations” that President Kennedy famously predicted would go nuclear by the 1970s.
 
Contrary to the impressions created by the biological metaphor, as political scientist Benoit Pelopidas has pointed out, the “proliferation” of nuclear weapons is also neither inevitable nor irreversible. South Africa, a non-NPT country which had secretly developed nuclear weapons by the 1980s, voluntarily dismantled its arsenal following the end of Apartheid. Belarus, Kazakhstan, and Ukraine, which inherited nuclear warheads following the collapse of the Soviet Union in 1991, also agreed to transfer them to Russia. Moreover, despite all the talk about the threat of nuclear terrorism, experts note a multitude of obstacles, both technical and political, for non-state actors to steal or assemble workable atomic devices.[1] Although many countries and terrorists are known to have harbored nuclear ambition at one point or another in the past – and some undoubtedly still do so today – we should not exaggerate the possibility of nuclear weapons acquisition by new countries and violent non-state actors and the potential threat that it might pose to international security.
 
The real dangers of nuclear proliferation, however, lie elsewhere. The NPT is supposed to be a bargain between the nuclear haves and have-nots. The non-nuclear countries agreed not to acquire or manufacture nuclear weapons in exchange for the pledge made by all parties, including the five nuclear-weapon states designated by the NPT (United States, Soviet Union/Russia, United Kingdom, France, and China), to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament.” The nuclear-armed countries, however, have consistently failed to keep their end of the deal.[2]
 
Meanwhile, the United States has repeatedly used or threatened to use military force to disarm hostile countries suspected to have clandestine nuclear weapons programs. Iraq is the most famous example of this, but as discussed below, U.S. officials also seriously considered preemptive attacks against nuclear facilities in China and North Korea. The United States is not alone in its penchant for unilateral military action. Israel, a U.S. ally widely believed to possess nuclear weapons, has also carried out a number of surprise airstrikes that destroyed an Iraqi nuclear reactor in 1981 and a suspected Syrian installation in 2007.[3]
 
The alleged “success” of the repeated use of force and its threat to stem the tide of nuclear proliferation, however, comes at a high cost. Such action may not only deepen the insecurity of the threatened nation and make it all the more determined to develop its nuclear capabilities as a deterrent, but also entails a serious risk of unintended escalation to a large-scale conflict. Anyone who tries to weigh the value of nuclear power in coping with the climate crisis thus must take stock of the history of militarized counter-proliferation policy that reflects and reinforces what historian Shane J. Maddock has called “nuclear apartheid,” a hierarchy of nations grounded on power inequality between the nuclear haves and have-nots.[4]

In October 1964, the People’s Republic of China successfully tested an atomic bomb, becoming the fifth country that demonstrated its nuclear weapons capabilities. The United States eventually acquiesced China’s nuclear status by the time it signed the NPT in 1968, which formally defined the nuclear-weapon state as a country that had manufactured and detonated a nuclear device prior to January 1, 1967.
 
Washington’s decision to tolerate a nuclear China, however, did not come without resistance. In fact, as historian Francis J. Gavin has noted, there is a striking parallelism between the U.S. perception of China during the 1960s and that of a “rogue state” today: China had already clashed with the United States during the Korean War, twice shelled the outlying islands of Taiwan, and invaded India over a disputed border; it strongly disputed the Soviet Union’s leadership in the Communist world and aggressively supported revolutionary forces around the world; and it consolidated a one-party rule and embarked on a series of disastrous political, economic, and social campaigns, most notably the Great Leap Forward and the Cultural Revolution.[5] Operating from the Cold War mindset, and with little information shedding light on the complexity of China’s foreign and domestic policies, senior U.S. officials feared that China’s nuclear weapons program would post a serious threat to the stability of East Asia and the international effort to prevent the further spread of nuclear weapons around the world.[6]
 
It is important to note that not all U.S. officials held such a grim view about China’s nuclear ambition and its consequences. Some believed that a nuclear-armed China would act rather cautiously, and President John F. Kennedy and Lyndon B. Johnson both tried to induce China by diplomatic means to abandon its nuclear program. As historians William Burr and Jeffrey T. Richelson have demonstrated, however, the Kennedy and Johnson administrations also developed contingency plans to disarm China by force. In a memo written in April 1963, the Joint Chiefs of Staff discussed a variety of military options, ranging from covert operations to the use of a tactical nuclear weapon, to coerce China into signing a test ban treaty.[7]
 
While the military was skeptical about the effectiveness of unilateral action and also cautious about the risk of retaliation and escalation, Kennedy and some of his senior advisers remained keen on military and covert operations. For instance, the President showed his interest in enlisting the Republic of China in Taiwan as a proxy to launch a commando raid against Chinese nuclear installations.[8] William Foster, director of the Arms Control and Disarmament Agency, later recalled that Kennedy had been eager to consider the possibility of an airstrike in coordination with, or with tacit approval of, the Soviet Union.[9] The idea of an air raid resurfaced in September 1964, on the eve of the Chinese test. Although Johnson and his advisers ultimately decided against the proposal, all agreed that, “in case of military hostilities,” the United States should consider “the possibility of an appropriate military action against Chinese nuclear facilities.”[10]
 
Despite all the talks about the use of force, the U.S. government ultimately refrained from taking such drastic action. The Soviet Union refused to discuss the possibility of joint military intervention, and the political costs and military risks of an unprovoked attack were too high. The failure to stop China’s nuclear weapons program, Gavin has pointed out, precipitated a major shift in U.S. nuclear policy toward creating a global nonproliferation regime with the NPT as its keystone.[11] However, these “proliferation lessons from the 1960s,” as Gavin has called, did not change the fundamental fact that the United States was willing to contemplate military action, to be carried out unilaterally if necessary, to prevent hostile countries from acquiring nuclear weapons. The NPT became a handy justification for such measures. This was abundantly clear when North Korea triggered another nuclear crisis thirty years later.

In March 1993, North Korea startled the world by announcing its decision to withdraw from the NPT. At issue was the IAEA’s demand for special inspections at nuclear facilities in Yongbyon to account for the amount of plutonium generated in an earlier uninspected refueling operation. The tension briefly subsided when, after bilateral talks with the United States, Pyongyang suspended the process of pulling out of the NPT and agreed to allow inspections at a number of installations. In March 1994, however, North Korea suddenly reversed its attitude, blocking IAEA inspectors from conducting activities necessary to complete their mission. The United States responded by declaring its intention to ask the United Nations Security Council to impose economic sanctions against North Korea.  
 
As the confrontation between the United States and North Korea escalated, President Bill Clinton decided to take all necessary measures to coerce Pyongyang into full compliance with the IAEA safeguards. In his memoirs, Clinton wrote that “I was determined to prevent North Korea from developing a nuclear arsenal, even at the risk of war.”[12] To leave no room for misunderstanding about his resolve, Clinton let his senior advisers and military commanders openly discuss contingency plans for military action. On February 6, The New York Times broke news on updated U.S. defense plans for South Korea in the event of a North Korean attack, describing a newly added option for a counteroffensive to seize Pyongyang and overthrow the regime of Kim Il Sung.[13] Meanwhile, Secretary of Defense William Perry talked tough, telling the press that “we would not rule out a preemptive military strike.”[14]
 
The talk about the use of force against North Korea was not an idle threat. In his memoirs, Perry has described contingency planning for military action. In May 1994, when North Korea began to remove the spent fuel rods containing plutonium from its reactor, the Defense Secretary ordered John Shalikhashvili (chairman of the Joint Chiefs of Staff) and Gary Luck (commander of the U.S. military forces in South Korea) to prepare a course of action for “a ‘surgical’ strike by cruise missiles on the reprocessing facility at Yongbyon.”[15] Three former U.S. officials, Joel S. Wit, Daniel B. Poneman, and Richard L. Gallucci, also confirmed that the strike plan was discussed at the highest level of the Clinton administration. On May 19, Perry, Shalikhashvili, and Luck briefed Clinton and his aides on the proposal for an air raid against the Yongbyon facilities, asserting that it would “set the North Korean nuclear program back by years.” Perry, however, reportedly stressed the “downside risk,” namely that “this action would certainly spark a violent reaction, perhaps even a general war.”[16] Clinton recalled that a “sobering estimate of the staggering losses both sides would suffer if war broke out” gave him pause.[17] As Perry has noted, the military option was still “‘on the table’, but very far back on the table.”[18]
 
The self-restraint of the Clinton administration and its commitment to a diplomatic solution have earned praise from many scholars and pundits – in sharp contrast to George W. Bush’s aggressive unilateralism. But the fact remains that Clinton and his aides considered the threat of preventive military action as permissible, even essential, to pressure North Korea into refraining from any suspicious nuclear activities. And their willingness to go to the brink of actual conflict created the tense policy environment that greatly diminished room for quiet diplomacy for a possible compromise while drastically raising the risk of accidents and miscalculations.
 
In this sense, the “peaceful” conclusion of the first North Korean nuclear crisis was a Pyrrhic one, reinforcing the belief widely held by the U.S. policy community that the United States must be prepared to use its military force unilaterally to uphold the global non-proliferation regime. It is thus no coincidence that, even after the disastrous outcomes of the Iraqi War fought in the name of nuclear nonproliferation, the U.S. government still continues to wage the dangerous game of brinkmanship with hostile powers suspected of pursuing the clandestine development of nuclear weapons.

What, then, does the history of U.S. counter-proliferation policy mean for the future use of nuclear power to combat climate change? An answer, I believe, lies in an accelerating shift in the nuclear geography. The New Policies Scenario of the International Energy Agency’s World Energy Outlook 2018, a global energy trend forecast based on policies and targets announced by governments, shows that the demand for nuclear power in 2017-40 will decrease in advanced economies by 60 Mtoe (millions of tons of oil equivalent), whereas it will increase in developing economies by 344 Mtoe. Of approximately 30 countries which are currently considering, planning, or starting nuclear power programs, many are post-colonial and post-socialist countries located in areas, including Central Asia, Eastern Europe, the Middle East, and South and Southeast Asia, where the United States is competing with other major and regional powers for greater influence.

​Added to this geopolitical layer is the nuclear supply game. While many Western conglomerates have recently decided to exit from nuclear exports due to swelling construction costs, Russian and Chinese state-owned companies have aggressively sold nuclear power plants to emerging countries, a move backed by their governments as part of their global strategies. Although Russia and China have generally cooperated with the United States in controlling nuclear exports, the recent U.S. withdrawal from the Iran nuclear deal has pitted Washington against Moscow and Beijing over the latter’s continued negotiations with Iran for nuclear cooperation. Given the growing tension between the United States on the one hand and Russia and China on the other, the expansion of civilian nuclear programs in key strategic regions is likely to be fraught with serious risks of an international crisis and even an armed conflict. 
 
The fundamental solution to the nuclear dilemma in the changing climate is simple: carry out the pledge made by all parties to the NPT, that is, to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control” (Article VI). A breakthrough toward this goal came in July 2017 when the United Nations General Assembly voted to adopt the first legally binding international agreement that prohibited nuclear weapons. All of the nuclear weapon states and most of their allies, however, refused to participate in the treaty negotiations.
 
Recently, Christopher Ashley Ford, assistant secretary of state for nonproliferation, has called the treaty as a “well-intended mistake,” insisting that a “better way” was to work within the NPT framework while taking steps to improve “the actual geopolitical conditions that countries face in the world.” If the IPCC is correct in its claim that we have only a little more than a decade to stop potentially catastrophic climate change, it is unlikely that the “pragmatic, conditions-focused program” described by Ford will significantly reduce risks of nuclear proliferation and militarized counter-proliferation in time. If so, then we must realize that the promotion of civilian nuclear power in a world of nuclear apartheid – a world in which the United States and its allies are not hesitant to use force to disarm and topple a hostile regime with nuclear ambition – may have no less catastrophic consequences for human society than climate change.

​Toshihiro Higuchi an assistant professor in the Edmund A. Walsh School of Foreign Service at Georgetown University. He is a historian of U.S. foreign relations in the 19th and 20th century. His research interests rest with science and politics in managing the trans-border and global environment.

[1] John Mueller, Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda (Oxford; New York: Oxford University Press, 2010), 161-179.

[2] Shane J. Maddock, Nuclear Apartheid: The Quest for American Atomic Supremacy from World War II to the Present (Chapel Hill: University of North Carolina Press, 2010), 1-2.  

[3] Dan Reiter, “Preventive Attacks against Nuclear Programs and the ‘Success’ at Osiraq,” Nonproliferation Review 12, no. 2 (2005): 355-371; Leonard S. Spector and Avner Cohen, “Israel’s Airstrike on Syria’s Reactor: Implications for the Nonproliferation Regime,” Arms Control Today 38, no. 6 (2008): 15-21.

[4] Shane J. Maddock, Nuclear Apartheid: The Quest for American Atomic Supremacy from World War II to the Present (Chapel Hill: University of North Carolina Press, 2010), 1-2.  ​
​
[5] Francis J. Gavin, Nuclear Statecraft: History and Strategy in America’s Atomic Age (Ithaca, NY: Cornell University Press, 2012), 75-76.

[6] William Burr and Jeffrey T. Richelson, “Whether to ‘Strangle the Baby in the Cradle’: The United States and the Chinese Nuclear Program, 1960-64,” International Security 25, no. 3 (2000/01): 55, 61-62. Also see Noam Kochavi, A Conflict Perpetuated: China Policy during the Kennedy Years (Westport, CT: Praeger, 2002).

[7] Ibid., 68-69.

[8] Ibid., 73.

[9] Ibid., 54.

[10] Document 49, Memorandum for the Record, September 15, 1964, in Foreign Relations of the United States, 1964-1968, vol. 30 (Washington: U.S.G.P.O., 1998).

[11] Gavin, 75-103. 

[12] Bill Clinton, My Life (New York: Vintage, 2005), 591.

[13] Michael R. Gordon, “North Korea’s Huge Military Spurs New Strategy in South,” New York Times, February 6, 1994, 1.

[14] Clinton, My Life, 591.

[15] William J. Perry, My Journey at the Nuclear Brink (Stanford, CA: Stanford University Press, 2015), 106. 

[16] Joel S. Wit, Daniel B. Poneman, and Robert L. Gallucci, Going Critical: The First North Korean Nuclear Crisis (Washington: Brookings Institution Press, 2003), 180.

[17] Clinton, My Life, 603.

[18] Perry, My Journey at the Nuclear Brink, 106. 

Shortly before uranium miner Gus Frobel died of lung cancer in 1978 he said, “This is reality. If we want energy, coal or uranium, lives will be lost. And I think society wants energy and they will find men willing to go into coal or uranium.”[1]
​
Frobel understood that economists and governments had crunched the numbers. They had calculated how many miners died comparatively in coal and uranium production to produce a given amount of energy. They had rationally worked out that giving up Frobel’s life was worth it.

I have come across these tables in archives. They lay out in columns the number of deaths to expect per megawatt year of energy produced. They weigh the ratios of deaths in uranium mines to those in coal mines. They coolly walk through their methodology in making these conclusions.

These numbers will show you that fewer people died in uranium mines to produce a certain amount of energy. But the numbers do not include the pages and pages I have read of people remembering spouses, parents, siblings, children who died in their 30s, 40s, 50s, and so on. The numbers do not include details of these miners’ hobbies or snippets of their poetry; they don’t reveal the particulars of miners’ slow and painful wasting away. Miners are much easier to read about as death statistics.

The erasure of these people trickles into debates about nuclear energy today. Any argument that highlights the dangers of coal mining but ignores entirely the plight of uranium miners is based on this reasoning. Rationalizations that say coal is more risky are based on the reduction of lives to ratios.

If we are going to make these arguments, we must first acknowledge entirely what we are doing. We must be okay with what Gus Frobel said and meant: that someone is going to have to assume the risk of energy production and we are just choosing whom. We must realize that it is no accident that these Cold War calculations permeate our discourse today, and what that means moving forward.

Promoters of nuclear energy have always tapped into fears about the environment in order to get us to stop worrying and learn to love the power plant. The awesome power of the atom announced itself to the world in a double flash of death and destruction when the United States dropped nuclear bombs on Hiroshima and Nagasaki in August 1945.  Following the end of World War II, growing tensions between the United States and the Soviet Union and the consequent Cold War helped spur on a proliferation of nuclear weapons production. As nuclear technology became more important and sought after, governments around the world fought against nuclear energy’s devastating first impressions, which were difficult to dislodge from the minds of the public. From the earliest days, in order to combat the atom’s fearsome reputation and put a more positive spin on things, policymakers began pushing its potential peaceful applications.
​
Nuclear technology and the environment were intertwined in many complex and mutually reinforcing ways. From as early as the 1940s, as historian Angela Creager has shown, the US Atomic Energy Commission used the potential ecological and biological application of radioisotopes as proof of the atom’s promising, non-militant prospects. By the 1950s, many hailed nuclear power as a way to escape resource constraint, underlining the comparatively small amount of uranium needed to produce the same amount of energy as coal. Using uranium was a way to conserve oil and coal for longer. In the 1960s, as the popular environmental movement grew, nuclear boosters appealed to the public’s concern for the planet by emphasizing the clean-burning qualities of nuclear energy.

Environmentalism spread around the world, with environmental protection slowly being enshrined in law in several different countries. Environmental concern and protection also became an important part of the Cold War battle for hearts and minds. Nuclear advocates successfully appealed to environmentalist sentiments by avoiding certain problems, such as the intractable waste that the nuclear cycle produced, and emphasizing others, namely, the way it did not pollute the air.

The main arguments of Cold War-era nuclear champions live on to this day. For many pro-nuclear environmentalists, who found these arguments appealing, the reasons to support nuclear energy were and continue to be: less uranium is needed than coal to produce the same amount of energy, nuclear energy is clean burning, radiation is “natural” and not something to be feared, and using nuclear energy will give us time to figure out different solutions to the energy crisis, which was once thought of as fossil fuel shortage and now leans more towards global warming.

In broad strokes, then, these arguments are a Cold War holdover, and so are the anachronistic blind spots that accompany them. They portray nuclear power production as a single snapshot of a highly complex cycle. Nuclear is framed as “clean burning” for a reason; the period when it is burning is the only point when it can be considered clean.  This reasoning made more sense when first promulgated because there was a hubris that accompanied nuclear technology, and part of this hubris was to assume that all of the issues that arose due to nuclear technology could and would be solved. Though that confidence is long-gone in general, it still lurks as an assumption that undergirds the argument for nuclear energy.

One of the biggest problems that we were once sure we could solve is nuclear waste disposal.  This problem has not been solved. It becomes more and more complex all the time, and the complexities tied up in the problem continue to multiply. Nuclear waste storage is still a stopgap measure, and most waste is still held on or near the surface in various locations, usually near where it is produced. The best long-term solution is a deep geological repository, but there are no such storage facilities for high-level radioactive waste yet.  Several countries that have tried to build permanent repositories have faced both political and geological obstacles, such as the Yucca Mountain project in the United States, which the government defunded in 2012.

Finland’s Onkalo repository is the most promising site. Many people who pay attention to these issues commend the Finnish government for successfully communicating with, and receiving consent from, the local community. But questions remain about why and how the people alive today can make decisions for people who will live on that land for the next 100,000 years. This timescale opens up various other questions about how to communicate risk through the millennia.  Either way, we will not know if Onkalo is ultimately successful for a really long time, while the kitty litter accident at the Waste Isolation Pilot Plant in New Mexico, USA, where radioactive waste blew up in 2014, hints at how easily things can go wrong and defy careful models of risk.

Promoters continue to use language that clouds this issue. Words such as “storage” and “disposal” obfuscate the inadequacies tied up in these so-called solutions. The truth is, disposal amounts to trying to keep waste from migrating by putting it somewhere and then trying to model the movements of the planet thousands of years into the future to make sure it stays where we put it. It is a catch-22. By ignoring the disposal problem, we kick the same can down the road that was kicked to us.  By developing a disposal system, we just kick it really, really far into the future. Either way, there is an antiquated optimism that still persists in the belief that,one way or another, we will work it out, or have successfully planned for every contingency with our current solutions.

Even if they do so inadequately, advocates of nuclear power often do acknowledge the back-end of the nuclear cycle.  They usually only do so to dismiss it, but at least it is addressed. By contrast, they entirely ignore the front-end of the cycle. This tendency is particularly strange because when uranium is judged against fossil fuels, the ways that coal and oil are extracted enter the conversation while uranium, in contrast, is rarely considered in such terms. We think of coal and oil as things that come from the earth, uranium also is mined and its processing chain is just as complex as the other forms of fuel we seek to replace with it.

Discussions of nuclear energy hardly ever mention uranium mining, possibly because uranium mining increasingly occurs in marginalized landscapes that are out of sight and out of mind (northern Saskatchewan in Canada and Kazakhstan are currently the biggest producers). But even for those who do pay attention to uranium mining, the problems associated with it are officially understood as something we have “figured out.”

The prevailing narrative is that, yes, many uranium miners died from lung cancer linked to their work in uranium mines, and yes, there was a lot of waste produced and then inadequately disposed of due to the pressures and expediencies of the Cold War nuclear arms race. But when officials acknowledged these problems, they implemented regulations and fixed them.

It follows that, because there is no longer a nuclear arms race, and because health and environmental authorities understand and accept the risks associated with mining activities, they have appropriately addressed and mitigated the problems linked to uranium production. Moreover, nuclear power generation, because it is separate from the arms race and the nefarious human radiation experiments that accompanied it, is safer and better for miners and communities that surround mines.

Some aspects of this narrative are true. Uranium miners around the world did labor with few protections through at least the late 1960s, after which conditions improved moderately in some places. Several governments introduced and standardized maximum radon progeny (the decay products of uranium that cause cancer among miners) exposure levels. More mines had ventilation, monitoring increased, and many places banned miners from smoking underground. By the 1970s and 1980s, many countries considered the health problem solved.

The issue with this portrayal is that the effectiveness of the introduction of these regulations is not very clear.  Allowing a few years for the implementation of regulations, most countries did not have mines at regulated exposure levels until at least the mid-1970s. If we then allow for at least a fifteen-year latency period of lung cancer—which is the accepted minimum even with very high exposures—then lung cancer would not begin to show until, at the very least, around the late 1980s or early 1990s.

By this period, however, the uranium-mining industry was collapsing. The Three Mile Island accident in 1979, the Chernobyl accident 1986, and the end of the Cold War arms race meant that plans for nuclear energy stalled and the demand for uranium plummeted. The uranium that did continue to be produced came from new mining regions and new cohorts of workers, or it affected people and places that the public and media ignored, or technology shifted and so fewer people faced the risks of underground uranium mining. There is little information about how and if the risks miners faced changed.

There is also a dearth of information about how these post-regulation miners compare to their pre-regulation counterparts.  One preliminary examinationof Canadian uranium miners, however, shows that miners who began work after 1970 had similar increased risk of mortality from lung cancer as those who began work in earlier decades. This suggests that there was either ineffective radon progeny reduction and erroneous reporting of radon progeny levels in mines or that there is something about the health risks in mines that are not quite understood.

There is another relatively well-known narrative about uranium mining that some commenters point to as something we have figured out and corrected. Due to the extremely effective activism of the Navajo Nation, beginning in the 1970s and continuing through to the present, many people are aware of the hardships Navajo uranium miners faced and, to a lesser degree, the continued legacy of abandoned mines and tailings piles with which they have to contend. High-profile advocates for the Navajo, such as former secretary of the interiorStewart Udall and several journalistic and scholarly books on Navajos and uranium mining, have added to this awareness. Few people realize when pointing to the Navajo case that there is still a lot of confusion surrounding the long-term effects of uranium mining on Navajo land. It is an ongoing problem with unsatisfactory answers.

Moreover, even though Navajo activists were adept at attracting attention to the problems they faced, many other uranium-mining communities cannot, do not want to, or have not been able to garner the same attention.  Uranium mining happened and continues to happen around the world, even though the health risks are poorly understood.  It is changing human bodies and landscapes to this day and affecting thousands of miners and communities. Those who work in mines are still making the trade-off between the employment the mine offers on the one hand, and the higher risk of lung cancer on the other.

The environmental effects of uranium mining also are poorly understood and inadequately managed with a view to the long-term. When mines are in operation, the waste from uranium mills, called tailings, are usually stored in wet ponds or dry piles.  Those who operate uranium mills try to keep these tailings from moving, and there are often government authorities that regulate these efforts, but tailings still seep into water, spread into soil, and migrate through food chains.

These problems relate to mines and mills in operation, but there are also several problems that companies and governments face with regards to mines and mills that are no longer in operation. The production of uranium has led to landscapes with several abandoned mines that are neglected, as well as millions of tons of radioactive and toxic tailings.  There are no good numbers for worldwide uranium tailings, but the International Atomic Energy Agency has estimatedthat the United States alone has produced 220 million tons of mill tailings and 220 million tons of uranium mine wastes.

Waste from uranium production is managed in similar ways around the world.  Using the same euphemistic language employed for nuclear waste coming out of the back-end of the nuclear cycle, tailings from uranium mills are often “disposed.” What disposal usually means is gathering tailings in one area, creating some kind of barrier to prevent erosion—this barrier can be vegetation, water, or rock—and then monitoring the tailings indefinitely to ensure they do not move.

The question that follows is whether or not these tailings are harmful, and the truly unsatisfactory answer is that we do not know. Studies of communities surrounding uranium tailings that consider how tailings affect community health are scarce, while those that do exist are conflicting, inconclusive, and often problematic.  While some studies, with a particular focus on cancer and death, argue that there are no increased illnesses linked to living in former uranium-mining areas, others have connected wastes from uranium production to various ailments, including kidney disease, hypertension, diabetes, and compromised immune system function.

Now, half of all uranium production around the world uses in situ leaching or in situ recovery to extract uranium.  Basically, uranium companies inject an oxidizing agent into an ore body, dissolve the uranium, and then pump the solution out and mill it without first having to mine it. The official line of thinking is that there are negligible environmental impacts stemming from this form of extraction. It certainly reduces risks for miners, but it is unlikely that it does not affect the environment.

The environmentalist argument for nuclear energy, particularly the clean-burning component, is very appealing in a time when our biggest concern is climate change.  Still, nuclear power is a band-aid technofix with many unknowns. The discussion surrounding nuclear energy has never fully grappled with the entire scope of the nuclear cycle, nor has it addressed the unique aspects of production of energy from metals that does not have parallels with fossil fuels. Making an argument about nuclear energy means examining all its risks in comparison with fossil fuels, and then coming to terms with the wealth of unknowns.
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It also means remembering and keeping in mind the bodies and landscapes making this option possible. To be a nuclear power advocate, especially as an environmentalist, one most also be an advocate for the safety of all nuclear workers. The problems uranium miners and uranium mining communities faced were never fully resolved and they are not fully understood. To promote nuclear power means to pay attention to the people and places that produce uranium and fighting to make sure they receive the protections they deserve for helping us carve our way out of this current problem.

Robynne Mellor received her PhD in environmental history from Georgetown University, and she studies the intersection of the environment and the Cold War. Her research focuses on the environmental history of uranium mining in the United States, Canada, and the Soviet Union. She tweets at @RobynneMellor.

There is no longer any debate. Humanity sits at the precipice of catastrophic climate change caused by anthropogenic greenhouse gas (GHG) emissions. Recent reports from the Intergovernmental Panel on Climate Change (IPCC)[1] and the U.S. Global Change Research Program (USGCRP)[2] provide clear assessments: to limit global warming to 1.5ºC above historic levels, thereby avoiding the most harmful consequences, governments, communities, and individuals around the world must take immediate steps to decarbonize their societies and economies.
 
Change is coming regardless of how we proceed. Doing nothing guarantees large-scale resource conflicts, climate refugee migrations from the global south to the global north, and mass starvation. Dealing with the problem in the future will be exceedingly more difficult, not to mention expensive, than making important changes immediately. The only question is what changes are necessary to address the scale of the problem facing humanity? Do we pursue strategies that allow us to maintain our current standard of living, consuming comparable amounts of (zero-carbon) energy? Or do we accept fundamental changes to humanity’s relationship to energy?
 
In his new book, The Wizard and the Prophet: Two Remarkable Scientists and Their Conflicting Visions of the Future of Our Planet, Charles C. Mann uses the life, work, and ideologies of Norman Borlaug (the Wizard) and William Vogt (the Prophet) to offer two typologies of twentieth century environmental science and thought. Borlaug represents the school of thought that believed technology could solve all of humanity’s environmental problems, which Mann refers to as “techno-optimism.” Vogt, by contrast, represents a fundamentally different attitude that saw only a drastic reduction in consumption as the key to solving environmental problems, which Mann (borrowing from demographer Betsy Hartmann) refers to as “apocalyptic environmentalism.”[3]
 
In the industrialized countries of the world, the techno-optimist approach enjoys the greatest support. Amongst those who think “technology will save us,” decarbonizing the economy means replacing fossil fuel energy with “clean” energy (i.e. energy that does not emit GHGs). Hydropower has nearly reached it global potential, and simply cannot replace fossil fuel energy. Solar, wind, and to some extent geothermal, are rapidly growing technological options for replacing fossil fuel energy. And as this series reveals, some debate exists over whether nuclear can ever play a meaningful role in a twenty-first century energy transition.
 
The quest for new clean energy pathways aims to rid the developed world of the blame for causing climate change without the need to fundamentally change the way of life responsible for climate change. In short, those advocating for clean energy hope to cleanse their moral culpability as much as the planet’s atmosphere. This is the crux of the climate change crisis and the challenge of how to respond to it. It is not a technical problem. It is a moral and ethical problem – the biggest the world has ever faced.
 
The USGCRP’s Fourth National Climate Assessment warns that the risks from climate change “are often highest for those that are already vulnerable, including low-income communities, some communities of color, children, and the elderly.”[4] Similarly, the IPCC’s Global Warming of 1.5ºC report insists that “the worst impacts tend to fall on those least responsible for the problem, within states, between states, and between generations.”[5] Furthermore, the USGCRP points out, “Marginalized populations may also be affected disproportionately by actions to address the underlying causes and impacts of climate change, if they are not implemented under policies that consider existing inequalities.” Indeed, the IPCC reports, “the worst-affected states, groups and individuals are not always well-represented” in the process of developing climate change strategies. The climate crisis has always been about the vulnerabilities created by energy inequalities. Decarbonizing the industrialized and industrializing parts of the world has the potential to avoid making things any worse for the most marginalized segments of the global population, but it wouldn’t necessarily make anything better for them either. At the same time, decarbonization strategies imagine an energy future in which people, communities, and countries with a high standard of living are under no obligation to make any significant sacrifices to their large energy footprints.
 
Over the last thirty years, industrialized countries, such as Germany, the United States, and Canada have consistently consumed considerably more energy per capita than non-industrialized or industrializing countries (Figure 1). In 2016, industrialized countries in North America and Western Europe consumed three to four times as much energy per capita as the global average, while non-industrialized countries consumed considerably less than the average.

Most of the research that has modelled 1.5ºC-consistent energy pathways for the twenty-first century assume that decarbonisation means continuing to use the same amount of, or only slightly less, energy (Figure 2).[6] Most of these models project that solar and wind energy will comprise a major share of the energy budget by 2050 (nuclear, it should be noted, will not). Curiously, the models also project a major role for biofuels as well. Most alarmingly, however, most models assume major use of carbon capture and storage technology, both to divert emissions from biofuels and to actively pull carbon out of the atmosphere (known as carbon dioxide reduction, or negative emissions). The important point here, however, is not the technological composition of these energy pathways, but the continuity of energy consumption over the course of the twenty-first century.

In case it is not already clear, I do not think technology will save us. Solar and wind energy technology has the potential to provide an abundance of energy, but it won’t be enough to replace the amount of fossil fuel energy we currently consume, and it certainly won’t happen quickly enough to avoid warming greater than 1.5ºC. Biofuels entail a land cost that in many cases involves competition with agriculture and places potentially unbearable pressure on fresh water resources. Carbon capture and storage assumes that pumping enormous amounts of carbon underground won’t have unintended and unacceptable consequences. Nuclear energy might provide a share of the global energy budget, but according to many models, it will always be a relatively small share. Techno-optimism is a desperate hope that the problem can be solved without fundamental changes to high-energy standards of living.
 
The current 1.5ºC-consistent energy pathways include no meaningful changes in the amount of overall energy consumed in industrialized and industrializing countries. The studies that do incorporate “lifestyle changes” into their models feature efficiencies, such as taking shorter showers, adjusting indoor air temperature, or reducing usage of luxury appliances (e.g. clothes dryers); none of which present a fundamental challenge to a western standard of living.[7] Decarbonization models that replace fossil fuel energy with clean energy reflect a desire to avoid addressing the role of energy inequities in the climate change crisis.
 
 
Climate change is a problem of global inequality, not just carbon emissions. Those of us living in the developed and developing countries of the world would like to pretend that the problem can be solved with technology, and that we would not then need to change our lives all that much. In a decarbonized society, the wizards tell us, our economy could continue to operate with clean energy. But it can’t. Any ideas to the contrary are simply excuses for perpetuating a world of incredible energy inequality. We need to heed the prophets and use dramatically less energy. We need to accept extreme changes to our economy, our standard of living, and our culture.

​Andrew Watson is an assistant professor of environmental history at the University of Saskatchewan.

Roughly 11,000 years ago, rising sea levels submerged Beringia, the vast land bridge that once connected the Old and New Worlds. Vikings and perhaps Polynesians briefly established a foothold in the Americas, but it was the voyage of Columbus in 1492 that firmly restored the ancient link between the world’s hemispheres. Plants, animals, and pathogens – the microscopic agents of disease – never before seen in the Americas now arrived in the very heart of the western hemisphere. It is commonly said that few organisms spread more quickly, or with more horrific consequences, than the microbes responsible for measles and smallpox. Since the original inhabitants of the Americas had never encountered them before, millions died.
 
The great environmental historian Alfred Crosby first popularized these ideas in 1972. It took over thirty years before a climatologist, William Ruddiman, added a disturbing new wrinkle. What if so many people died so quickly across the Americas that it changed Earth’s climate? Abandoned fields and woodlands, once carefully cultivated, must have been overrun by wild plants that would have drawn huge amounts of carbon dioxide out of the atmosphere. Perhaps that was the cause of a sixteenth-century drop in atmospheric carbon dioxide, which scientists had earlier uncovered by sampling ancient bubbles in polar ice sheets. By weakening the greenhouse effect, the drop might have exacerbated cooling already underway during the “Grindelwald Fluctuation:” an especially frigid stretch of a much older cold period called the “Little Ice Age."

Last month, an extraordinary article by a team of scholars from the University College London captured international headlines by uncovering new evidence for these apparent relationships. The authors calculate that nearly 56 million hectares previously used for food production must have been abandoned in just the century after 1492, when they estimate that epidemics killed 90% of the roughly 60 million people indigenous to the Americas. They conclude that roughly half of the simultaneous dip in atmospheric carbon dioxide cannot be accounted for unless wild plants grew rapidly across these vast territories.
 
On social media, the article went viral at a time when the Trump Administration’s wanton disregard for the lives of Latin American refugees seems matched only by its contempt for climate science. For many, the links between colonial violence and climate change never appeared clearer – or more firmly rooted in the history of white supremacy. Some may wonder whether it is wise to quibble with science that offers urgently-needed perspectives on very real, and very alarming, relationships in our present.
 
Yet bold claims naturally invite questions and criticism, and so it is with this new article. Historians – who were not among the co-authors – may point out that the article relies on dated scholarship to calculate the size of pre-contact populations in the Americas, and the causes for their decline. Newer work has in fact found little evidence for pan-American pandemics before the seventeenth century.

More importantly, the article’s headline-grabbing conclusions depend on a chain of speculative relationships, each with enough uncertainties to call the entire chain into question. For example, some cores exhumed from Antarctic ice sheets appear to reveal a gradual decline in atmospheric carbon dioxide during the sixteenth century, while others apparently show an abrupt fall around 1590. Part of the reason may have to do with local atmospheric variations. Yet the difference cannot be dismissed, since it is hard to imagine how gradual depopulation could have led to an abrupt fall in 1590.
 
To take another example, the article leans on computer models and datasets that estimate the historical expansion of cropland and pasture. Models cited in the article suggest that the area under human cultivation steadily increased from 1500 until 1700: precisely the period when its decline supposedly cooled the Earth. An increase would make sense, considering that the world’s human population likely rose by as many as 100 million people over the course of the sixteenth century. Meanwhile, merchants and governments across Eurasia depleted woodlands to power new industries and arm growing militaries.

In any case, models and datasets may generate tidy numbers and figures, but they are by nature inexact tools for an era when few kept careful or reliable track of cultivated land. Models may differ enormously in their simulations of human land use; one, for example, shows 140 million more hectares of cropland than another for the year 1700. Remember that, according to the new article, the abandonment of just 56 million hectares in the Americas supposedly cooled the planet just a century earlier!

If we can make educated guesses about land use changes across Asia or Europe, we know next to nothing about what might have happened in sixteenth-century Africa. Demographic changes across that vast and diverse continent may well have either amplified or diminished the climatic impact of depopulation in the Americas. And even in the Americas, we cannot easily model the relationship between human populations and land use. Surging populations of animals imported by Europeans, for example, may have chewed through enough plants to hold off advancing forests. Moreover, the early death toll in the Americas was often also especially high in communities at high elevations: where the tropical trees that absorb the most carbon could not go.

In short, we cannot firmly establish that depopulation in the Americas cooled the Earth. For that reason, it is missing the point to think of the new article as either “wrong” or “right;” rather, we should view it as a particularly interesting contribution to an ongoing academic conversation. Journalists in particular should also avoid exaggerating the article’s conclusions. The co-authors never claim, for example, that depopulation “caused” the Little Ice Age, as some headlines announced, nor even the Grindelwald Fluctuation. At most, it worsened cooling already underway during that especially frigid stretch of the Little Ice Age.

For all the enduring questions it provokes, the new article draws welcome attention to the enormity of what it calls the “Great Dying” that accompanied European colonization, which was really more of a “Great Killing” given the deliberate role that many colonizers played in the disaster. It also highlights the momentous environmental changes that accompanied the European conquest. The so-called “Age of Exploration” linked not only the Americas but many previously isolated lands to the Old World, in complex ways that nevertheless reshaped entire continents to look more like Europe. We are still reckoning with and contributing to the resulting, massive decline in plant and animal biomass and diversity. Not for nothing do some date the “Anthropocene,” the proposed geological epoch distinguished by human dominion over the natural world, to the sixteenth century. 

All of these issues also shed much-needed light on the Little Ice Age. Whatever its cause, we now know that climatic cooling had profound consequences for contemporary societies. Cooling and associated changes in atmospheric and oceanic circulation provoked harvest failures that all too often resulted in famines. In community after community, the malnourished repeatedly fell victim to outbreaks of epidemic disease, and mounting misery led many to take up arms against contemporary governments.​ Some communities and societies were resilient, even adaptive in the face of these calamities, but often partly by taking advantage of the less fortunate. ​Whether or not the New World genocide led to cooling, the sixteenth and seventeenth centuries offer plenty of warnings for our time.

Works Cited:

Archer, S. "Colonialism and Other Afflictions: Rethinking Native American Health History." History Compass 14 (2016): 511-21.

Crosby, Alfred W. “Conquistador y pestilencia: the first New World pandemic and the fall of the great Indian empires.” The Hispanic American Historical Review 47:3 (1967): 321-337.

Crosby, Alfred W. The Columbian Exchange: Biological and Cultural Consequences of 1492. Westport: Greenwood Press, 1972. Alfred W. Crosby, Ecological Imperialism: The Biological Expansion of Europe, 900-1900, 2nd Edition. Cambridge: Cambridge University Press, 2004.

Degroot, Dagomar. “Climate Change and Society from the Fifteenth Through the Eighteenth Centuries.” WIREs Climate Change Advanced Review. DOI:10.1002/wcc.518

Degroot, Dagomar. The Frigid Golden Age: Climate Change, the Little Ice Age, and the Dutch Republic, 1560-1720. New York: Cambridge University Press, 2018.

Gade, Daniel W. “Particularizing the Columbian exchange: Old World biota to Peru.” Journal of Historical Geography 48 (2015): 30.

Goldewijk, Kees Klein, Arthur Beusen, Gerard Van Drecht, and Martine De Vos, “The HYDE 3.1 spatially explicit database of human‐induced global land‐use change over the past 12,000 years.” Global Ecology and Biogeography 20:1 (2011): 73-86.

Jones, Emily Lena. “The ‘Columbian Exchange’ and landscapes of the Middle Rio Grande Valley, AD 1300– 1900.” The Holocene (2015): 1704.

Kelton, Paul. "The Great Southeastern Smallpox Epidemic, 1696-1700: The Region's First Major Epidemic?". In R. Ethridge and C. Hudson, eds., The Transformation of Southeastern Indians, 1540-1760. 

Koch, Alexander, Chris Brierley, Mark M. Maslin, and Simon L. Lewis. “Earth system impacts of the European arrival and Great Dying in the Americas after 1492.” Quaternary Science Reviews 207 (2019): 13-36

McCook, Stuart. “The Neo-Columbian Exchange: The Second Conquest of the Greater Caribbean, 1720-1930.” Latin American Research Review 46: 4 (2011): 13.
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McNeill, J. R. “Woods and Warfare in World History.” Environmental History, 9:3 (2004): 388-410.

Melville, Elinor G. K. ​A Plague of Sheep: Environmental Consequences of the Conquest of Mexico. Cambridge: Cambridge University Press, 1997.

PAGES2k Consortium, “A global multiproxy database for temperature reconstructions of the Common Era.” Scientific Data 4 (2017). doi:10.1038/sdata.2017.88.

Parker, Geoffrey. Global Crisis: War, Climate Change and Catastrophe in the Seventeenth Century. New Haven: Yale University Press, 2013. 

Sigl, Michael et al., "Timing and climate forcing of volcanic eruptions for the past 2,500 years." Nature 523:7562 (2015): 543.

Riley, James C. "Smallpox and American Indians Revisited." Journal of the History of Medicine and Allied Sciences 65 (2010): 445-77. 

Ruddiman, William. “The Anthropogenic Greenhouse Era Began Thousands of Years Ago.” Climatic Change 61 (2003): 261–93.

Ruddiman, William. Plows, Plagues, and Petroleum: How Humans Took Control of Climate. Princeton, NJ: Princeton University Press, 2005

Williams, Michael. Deforesting the Earth: From Prehistory to Global Crisis. Chicago: University of Chicago Press., 2002.