Note: originally posted on The Otter, blog of the Network in Canadian History and Environment (NiCHE).
On February 10th I embarked on the first leg of a long voyage from Toronto to Goa, a former Portuguese enclave nestled among the beaches of western India. After enduring the concrete monolith that is Frankfurt’s international airport, I finally boarded my second flight and flew south through Turkey, past Syria, across Iran and down towards Mumbai. I left the plane at an hour past midnight. Mosquitos swarming through the airport quickly prompted me to take the malaria medication that would later give me incredibly vivid dreams. Hours later the shock of a violent landing in Goa was nothing compared to the culture shock that followed. As I left the airport and stepped onto the rust-coloured soil I saw signs promoting European luxury vehicles or American cologne towering over slums and endless trash amid lush tropical beauty. After three sunrises and two sunsets without sleep I finally arrived at my hotel, ignoring for the moment the hand-sized spider dangling near my door.
For those planning to attend next month’s ASEH conference, Toronto does not look like this.
With the help of funding generously provided by Network in Canadian History and Environment (NiCHE), I had travelled nearly 13,000 kilometers to attend the fourth Open Science Meeting (OSM) organized by the Past Global Changes (PAGES) initiative. A core project of the International Geosphere-Biosphere Programme, PAGES has over 5000 subscribing scientists across more than 100 countries. Because research supported by PAGES explores past environments to create a roadmap for the future, the initiative is especially concerned with climate change. Every four years its Open Science Meeting is held in a new location, and in case the Olympic parallels were not obvious enough a “PAGES lamp” was lit at the opening ceremonies. It may not have resembled London’s burning torch, but it did avoid the mishap that embarrassed my fellow Canadians at the Vancouver Olympics.
It’s easy for historians to forget that we don’t have a monopoly over the interpretation of the past. There’s nothing like a scientific conference to remind us that we can only access a tiny sliver of the very recent past, that other disciplines can find voices which speak to the present in sources beyond the documents we hold sacred. Many of the scientists at the OSM reconstructed past climates to measure the significance of modern warming, to unravel how climatic shifts influence different environments, and to provide a clearer picture of the world’s natural history.
In papers and posters scientists presented results derived from the exhaustive analysis of, for example, changes in the growth of trees, the thickness of permanent ice cover and the scope of lakebed deposits. Conclusions were compared with other data that measured shifts in animal ranges, tree lines or glacial extent, all of which can be used to reconstruct changes in regional temperature or precipitation. Evidence from these so-called “proxies” was weighed against a range of sophisticated models, enabling projections of climates past that move seamlessly into the present and future.
Not surprisingly, correlating fluctuations in diverse proxy records and tying them to climatic trends is hardly straightforward. Physicist Ashoka Kumar Sinhvi gave an opening keynote address that exposed the frequently overlooked complexity of linking different kinds of data between different environments at different scales, revealing the limitations of our understanding of past and future climates. Later in the day that concept was echoed by André Berger, who explained how the intricate constellation of influences that shapes the global climate is never stable, complicating the attempt to find historical analogues for our present condition. Sinhvi, Berger and others helped frame the rich data presented in the papers and posters that followed by demonstrating yet again that in science, as in history, the past is opaque, unstable, and forever subject to interpretation.
Of course, that never stops us from seeking more information and, in turn, greater clarity. Some particularly fascinating papers explored past Antarctic climates at a time when the Antarctic Peninsula is warming at a rate of 5.3° C per century. Michael Weber presented findings that reveal how the Antarctic ice sheet is much more reactive to atmospheric Carbon Dioxide than previously believed. Robert Mulvaney then described how the rate of Antarctic melting, unprecedented in the past millennium, likely had analogues in the distant past when ice shelves were entirely absent. Medieval warmth and early modern cooling, familiar to historians of climates past, apparently were not felt in Antarctica. On the other hand, Guillaume Leduc presented exhaustive findings that, while skewed towards the Atlantic region, nevertheless suggested that the “Little Ice Age” between the fourteenth and nineteenth centuries strongly affected global sea surface temperatures. Those results may have critical implications for the nascent field of marine environmental history, which until now has not adequately considered climatic fluctuation.
High times in the Low Countries during the “Little Ice Age.”
To unravel histories that bridge culture and nature, environmental historians require some scientific literacy, yet I wasn’t sure what to expect as I prepared to give at a talk at a conference where formulas were ubiquitous and historiography unheard of. I argued that documentary evidence can improve the accuracy of reconstructions of temperature or precipitation, giving us a way of testing meteorological patterns recorded by the kinds of sources unearthed by scientists. Accustomed to the critical analysis of diverse documents, historians are ideally situated to filter documents through the kind of methodology that lets us quantify past weather observations and, in turn, reconstruct the climatic past. Moreover, while tree rings or ice cores rarely provide much more than seasonal resolution, surviving documents can record weather with far greater temporal precision, and some even chart hourly changes.
Most importantly, documentary evidence grants us access to past wind intensity or direction, weather conditions that are less easily measureable through the analysis of scientific proxy data. For centuries it was necessary for European mariners to estimate longitude by calculating a ship’s speed, direction and any leeway in its course, for which the most important influence was wind. Hence many logbooks kept aboard ships abound with reliable and quantifiable meteorological information taken several times on virtually every day of the vessel’s journey. The bulk of my talk presented results from English and Dutch ship logbooks, which suggest that easterly winds increased in the late seventeenth century as the climate cooled across the North Sea.
I was relieved and delighted by the reception I received from the scientists in the audience. More importantly, it was heartening to see the importance of interdisciplinary cooperation in the new “Future Earth” project spearheaded by the International Geosphere-Biosphere Programme. Still, many scholars in both the sciences and the humanities continue to take a passive approach to building connections between disciplines. Conferences like the PAGES OSM have existed for decades, yet many historians fail to realize that their insights are needed and desired. Similarly, most presenters at the upcoming ASEH conference are historians, and scientists or engineers remain underrepresented. Establishing connections between institutions like NiCHE, the ASEH, PAGES and the Climate History Network (CHN) can help move us forward, but what’s even more valuable is feedback from those who have benefitted from conferences in another discipline.
Slums bordering a wealthy part of Mumbai. Though poorly represented in this picture, the smog was overwhelming.
After the conference in Goa I spent a few days in the vast metropolis of Mumbai. My plane was delayed, and as it finally approached the city our pilot was forced to circle the airport for a few minutes before we could land. The slums in Mumbai are so vast that their full extent can only be grasped from the air. As I shifted in my leather seat I glimpsed the innumerable shanties, clustered around open sewage, barely visible through the purple smog. The impoverished people far below, and countless millions like them, will suffer most as our planet continues to warm, yet their voices are never heard in academic or political conferences. The quest to understand climate change must become more inclusive, not just of other academic disciplines, but of all voices, past and present, learned and “unlearned,” rich and poor.
For those interested in climates past and present, trees do more than absorb carbon dioxide. Seasonal changes in cellular growth near the bark of a tree leave rings buried in its wood. The size of those records is tied to the growth of the tree; a good year will imprint a thick ring, while hard times leave mere slivers. Anyone who's ever owned a plant will understand that most trees need abundant sun, moderate temperatures and sufficient water. Of course, gardeners are aware that different plants - from weeds to trees - respond to different conditions. By researching the peculiar tastes of various tree species climatologists can use tree trunks to reconstruct yearly fluctuations in temperature and precipitation, sometimes over hundreds of years.
The resulting reconstructions have been featured on this site ("Does tree ring data reflect global cooling? July 9, 2012"). With good reason: tree rings enable reliable climatic reconstruction for most parts of the world, especially in temperate regions where the contrast between seasons usually yields more discernible rings. However, most sources useful for the reconstruction of past climates have their shortcomings, and these inevitably stimulate controversy. Tree rings are no exception. Sulphur released into the atmosphere by volcanic eruptions of sufficient size at the right locations can cool the world's average temperature. Strangely that global cooling, while recorded by other sources and climate models, is not represented to the same extent in tree ring data. A new study by Michael Mann, Jose Fuentes and Scott Rutherford in the journal Nature Geoscience has suggested that trees in some altitudes simply stop growing when temperatures plummet below a certain threshold. Many trees would survive, and for those trees the next tree ring would therefore record growth only after temperatures had rebounded above that threshold. It is possible, therefore, that climatic reconstructions compiled using tree rings are less accurate than previously thought.
No fewer than twenty-three scientists responded to these claims, and the subsequent debate is nicely summarized by Scott Johnson at Ars Technica. Whatever its resolution, the controversy highlights the weaknesses of climatic reconstructions that use just one kind of source. The most reliable reconstructions of past climates and, for that matter, human history are generally those that incorporate a wide-ranging and diverse selection of evidence. For some weather conditions, in some places, for some time, evidence useful for climatic reconstruction can include all manner of sources, involving not only tree rings, plankton deposits, ice cores and other records accessible by scientists, but also surviving documentary records from literate cultures.
Logbook kept aboard the vessel "Wapen van Hoorn," sailing from Holland to Asia in 1627.
The cross-disciplinary dialogue encouraged by this diversity of sources can break down, however, when scholars broaden their focus. Changes in weather conditions like wind direction that may be associated with climatic fluctuation aren't easily reflected in scientific data. Reconstructions therefore rely heavily on, for example, logbooks kept aboard ships that record daily weather. On the other hand, past cultures that communicated information orally have left us few sources useful for climatic reconstruction, and when piecing together the climatic shifts that affected such civilizations we must depend on, for example, tree ring data. As our interest enters the distant past we leave behind both documentary sources and tree ring data, and our reconstructions must increasingly rely on ice cores. Beyond 1.5 million years into the past we must turn to sediments and consider increasingly indirect consequences of climatic fluctuation, as our reconstructions diminish in accuracy.
Ultimately we cannot measure or understand global warming without reference to the past; after all, the world must be warming relative to what came before. Moreover, our best guess of what may happen in the future can come through an analysis of warmer (and colder) periods in our past. For that reason it is critical that we grasp the limitations of the sources that we use to reconstruct the climates of that past. Ultimately the best answers are always found through diversity: diversity of sources, methodologies, and perspectives.
Note: I will be discussing some of these themes next week at the PAGES Open Science Meeting
in Goa, India.
Whether consciously or unconsciously, most scholars study something important to their societies. The walls of the ivory tower are, in fact, quite porous. It's no surprise that the genre of history that deals with environmental issues - environmental history - grew out of the debates surrounding the use of DDT. No surprise, either, that academics within disciplines from anthropology to economics are increasingly considering the influence of climate change just as the effects of global warming are becoming painfully obvious. Now more than ever, research into past climates is not just for scientists. If environmental history grew steadily in the decades since its conception, so too did its semi-autonomous, interdisciplinary cousin: climate history, or historical climatology. This site regularly describes some of the more interesting work published by historical climatologists, before considering how it can reframe today's environmental issues. Equally striking, however, is what's not (yet) published, but spoken. Testament to the growing importance of climate history within environmental history, interviews about past climates have aired this year on two of the major audio resources in the discipline: Nature's Past and Environmental History Resources. Moreover, last year the growing diversity of climate history was well represented at the major conference for the North American branch of environmental history. In Madison, Wisconsin, papers explored how a shifting climate influenced issues ranging from nineteenth century famines in the far north to the construction of the St. Petersburg ice palace during the frigid winter of 1740. Even more topics are on this year's agenda. In Toronto climate change will be connected to cold war national security, the history of Lake Superior, Alberta's fossil fuel economy, the hydrology of central Mexico, warfare down the Danube, early modern transportation, and much more.
As the study of past climate change claims an increasingly important place within environmental history, it has also entered the mainstream of the historical profession. At this year's meeting for the American Historical Association - the largest conference in the discipline - climate history was featured in three back-to-back sessions. As described by Sam White of the Climate History Network, historians unraveled how past climatic variability influenced hurricanes in New Orleans, agricultural sustainability, and human history across many thousands of years. Rising interest in climate change within history and other non-scientific disciplines is obvious in published scholarly literature. It is equally apparent online and at conferences, where the insights described and discussed have equal relevance for our struggle to make sense of a warming planet.
Article originally posted on ActiveHistory.ca. In recent weeks widespread outrage over the publication of Kate Middleton’s topless photos has existed in strange parallel with a decidedly muted response to a shocking acceleration of Arctic melting. While every day brought new stories of royal indignation and litigation to the front pages of major newspapers, concern over the plight of our increasingly topless planet was tucked away in corners of the internet, where many comments were, as ever, skeptical at best. Nevertheless, our destruction or, at least, transformation of the planet’s environment continues despite our apathy and cynicism. This summer Arctic ice cover fell to 3.41 square kilometers, a decline by an area the size of Texas against the previous minimum and some 50% lower than the average between 1979 and 2000. The reasons for enduring public skepticism of climate science and global warming have been examined at length – most eloquently in Naomi Oreskes’ and Eric Conway’s Merchants of Doubt – but the causes for the apathy of believers are less clear.
Upon encountering present-day mysteries our natural inclination as “active” historians is to sift through the past for context and, perhaps, answers. This article proceeds along similar lines, and it is the fourth in a series that explores how historians can shed light on global warming and its consequences. My research unravels relationships between early modern climatic fluctuations and the commercial, military and cultural histories of the Dutch Republic in the seventeenth century. Although those climatic fluctuations were collectively part of a relatively cool climate known as the “Little Ice Age,” average European temperatures during the period could change by nearly 2 degrees Celsius in just a few years. That pales in comparison to the likely scale of future anthropogenic warming, but for historians seeking insight into the climatic shifts we’ve already experienced the Little Ice Age is a great place to look.
The problem is, of course, that most societies within early modern Europe bore little resemblance to our own, and the historical writing we examine to contextualize the present was recorded by observers who frequently perceived weather very differently than we do now. In that alien world the Dutch Republic was unique, a society with capitalist socio-economic structures that seem instantly familiar, and were expressed in everything from remarkable rates of urbanization to incessant financial speculation. Admittedly not many of us are rabid Calvinists or troll the North Sea for herring, but searching the historical record for perfect analogues to ourselves is, of course, impossible. The surviving records kept by the politicians, merchants, farmers and mariners of the Republic provide some of history’s best insights into how we approach a changing climate.
After countless hours spent reading tattered correspondence, water-stained ship logbooks and half-burned diary entries - and thanking the Dutch archival system for its growing commitment to digitalization – a pattern emerges for the weary environmental historian of the Dutch Republic. In the seventeenth century Netherlands, those furthest removed from the environmental necessities of life were least likely to appreciate the importance of weather, even in a country prone to devastating storm floods. Logbooks kept aboard Dutch sailing ships abound with meteorological observation because recording the influence of wind was critical for contemporary navigation. Moreover, the seaworthiness of the vessel, the survival of its stores and the health of its crew were strongly tied to the weather that prevailed during a journey. No surprise, then, that during gales sailors scribbled fearful notes in the margins of their logs, before describing their relief when the weather cleared. Scattered among these reflections are hints that mariners whose work bound them to defined geographic locations perceived changes in patterns of prevailing weather related to shifts in the early modern climate. On the other hand, letters sent by the Republic’s political elite from its many urban centres have limited value for the environmental historian. Johan de Witt, the Republic’s leading political figure in the mid-seventeenth century, was apparently far more concerned about the financial ramifications of the state’s rising debt than even the most severe weather events of his time. To paraphrase Mark Twain, history may not exactly repeat itself, but it does have a tendency to rhyme.
For sailors, such apathy was not an option. The most telling examples of the tension occasionally kindled by these very different attitudes come from the naval wars in which the Republic was embroiled for much of its tenure as a European great power. The weather of the First Anglo-Dutch War was unusually stormy, although the causes were likely unrelated to a broader climatic shift. Fall and winter in the North Sea is almost always tempestuous, but in 1653 the Republic’s situation looked desperate, and in late October the Dutch Admiral – the wonderfully named Witte de With – was still on convoy duty. As he returned to the islands that surrounded the interior waters of the Republic his supplies were low and his crew was mutinous. The Republic’s governing body decided that Witte and his fleet should receive their supplies at sea, to prevent widespread desertion upon arrival at port. In a series of increasingly desperate letters De With begged his superiors to reconsider. Leaving the fleet at sea in the unpredictable and often violent autumn weather was courting suicide, De With insisted, but his masters were unmoved. On November 7th De With’s predictions came to pass when a severe gale sunk eleven warships and drowned some 1,400 seamen.
Historians frequently wrestle with the challenge of creating inclusive histories for societies in which literacy was the privilege of the elite. While those of us who piece together the history of climate frequently use sources that have been overlooked by other historians, we also require the kind of continuous, quantifiable records that were not usually kept by the poor. We may use the logbooks compiled by naval officers where other historians read the correspondence of wealthy merchants, but the reflections of ordinary sailors and dock workers are too often lost to us, as well. Of course, it was often precisely the poor – both urban and rural – whose work and play was most rooted in the unique environment of the Dutch Republic. Consequently, what we do know about, for example, small-scale farmers is intriguing. When the early modern climate cooled and persistent freezing halted travel through the Republic’s many canals, farmers abandoned their boats and used sleds to transport their goods. By switching easily between different modes of transportation, farmers, so attuned to the weather, adapted better than most within the Dutch Republic.
Today, most of us live in concrete jungles that may be oppressed by heat and cold but seem far removed from the environmental consequences of those fluctuations in temperature. A book I recently read about the shipwrecked child of a zookeeper included a passage that, for the environmental historian, provided a thought-provoking summary of the concept of “home.” To the protagonist of Life of Pi, home is a place where the environmental necessities of life, otherwise scattered across a vast geographic expanse, are collected for our convenience. The environmental historian will, of course, note that those environmental resources are not collected but rather connected for our benefit; no food is stored within our urban apartments that did not come from outside. The disastrous droughts of the past summer have reminded some of us that the environmental networks that sustain our urban lives are already strained in the face of an accelerating climatic shift, although many within the American states most affected were likely more impressed with Paul Ryan’s workout regime.
Ultimately, separation from the environments that support us has more to do with our psychology than our geography. As the climate cooled in the late seventeenth century Adriaen van der Goes, a lawyer in The Hague, described weather patterns and their repercussions in vivid letters to his brothers. Neither class nor geography excuses our apathy. Like the politicians who doomed De With’s fleet, we should know better, and, in knowing, we should care.
In just 27 seconds, NASA has presented one of the most effective summaries of our warming climate available anywhere on the internet. Using reliable instrumental data, this quick video captures the tail end of the Little Ice Age (depending how you want to date it), the rise in early twentieth century temperatures, the brief cooling of the early 1940s, and the longer cooling of the 1960s and '70s. Then, the final 10 seconds of the graph reveal how the rising concentration of atmospheric greenhouse gases is rapidly heating our planet, particularly at the poles. Relevant to that polar heating: this year's shocking Arctic ice melt, and the building awareness that the North Pole's sea ice is likely melting 50% faster than was predicted by most scenarios previously developed by scientists.