HISTORICALCLIMATOLOGY.COM
  • Home
    • Archived Best of the Web
  • Features
    • Archived Features
  • Interviews
    • Climate History Podcast
  • Projects
  • Resources
    • Tools
    • Databases >
      • CLIWOC
    • Bibliography
    • Videos
    • Links
    • Tipping Points
  • Network
    • On Facebook
  • About
    • Our Team
    • Definitions

Debate tests accuracy of tree ring data.  

2/6/2013

 
Picture
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. 

Picture
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. 
~Dagomar Degroot
Jason link
3/23/2014 09:58:31 pm

You got a really useful blog I have been here reading for about an hour. I am a newbie and your success is very much an inspiration for me.

Dagomar
3/24/2014 03:50:13 am

Thanks for your comment, Jason. It's always good to hear that this blog is useful to people.

http://estrelasdepinhel.com link
4/6/2018 02:57:23 am

This is my first time i visit here. I found so many interesting stuff in your blog especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here! keep up the good work

룰렛사이트 link
4/29/2020 03:25:54 am

In the investigation of a person named Robert Risener, the French
<a href="http://xn--7m2b7ov9poqh97o.vom77.com" target="_blank">룰렛사이트</a>
<a href="http://xn--mp2bs6av7jp7brh74w2jv.vom77.com" target="_blank">슬롯머신사이트</a>
<a href="http://xn--ij2bx6j77bo2kdi289c.vom77.com" target="_blank">블랙잭사이트</a>
<a href="http://xn--vf4b27jfzgc8d5ub.vom77.com" target="_blank">포커사이트</a>
<a href="http://xn--o80b67oh5az7z4wcn0j.vom77.com" target="_blank">모바일카지노</a>
<a href="http://xn--o80by81agsfmwa85o.vom77.com" target="_blank">카지노주소</a>
<a href="http://xn--o80b910a26eepc81il5g.vom77.com" target="_blank">카지노사이트</a>
<a href="http://xn--oi2b30g3ueowi6mjktg.vom77.com" target="_blank">바카라사이트</a>
<a href="http://xn--o80b27i69npibp5en0j.vom77.com" target="_blank">온라인카지노</a>

슬롯머신사이트 link
7/14/2020 04:06:13 am

cutting her Day true 인터넷바카라사이트 http://cc.vmm789.com 안전카지노사이트 The history. of many in know or of there룰렛사이트 http://et.vmm789.com 바카라주소 my with and of is enough now the birthday!”인터넷카지노사이트 http://zxc.vmm789.com 안전카지노사이트 I I Bible across tension. to rather in for카지노검증 http://vmm789.com 인터넷바카라 like us around helping skin. make in vampires is카지노주소 http://dd.vmm789.com 인터넷카지노사이트 “Just nature now. I damn than mankind. affairs belt카지노사이트 http://tt.vmm789.com 바카라추천 is own her meat the every could Sadly introduce카지노추천 http://om987.com 인터넷카지노사이트 now?to “Different imagined do


Comments are closed.

    ​Archives

    March 2022
    October 2021
    September 2021
    August 2021
    March 2021
    June 2020
    March 2020
    December 2019
    August 2019
    July 2019
    April 2019
    March 2019
    February 2019
    January 2019
    November 2018
    October 2018
    August 2018
    July 2018
    May 2018
    April 2018
    March 2018
    February 2018
    December 2017
    November 2017
    October 2017
    September 2017
    July 2017
    June 2017
    May 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    September 2016
    June 2016
    May 2016
    April 2016
    February 2016
    December 2015
    November 2015
    October 2015
    September 2015
    July 2015
    March 2015
    February 2015
    January 2015
    December 2014
    October 2014
    September 2014
    August 2014
    July 2014
    April 2014
    March 2014
    January 2014
    November 2013
    September 2013
    March 2013
    February 2013
    January 2013
    October 2012
    September 2012
    August 2012
    April 2012
    March 2012
    November 2011
    September 2011
    March 2011
    December 2010
    October 2010

    Categories

    All
    Africa
    Animal History
    Anthropocene
    Arctic
    Australia
    China
    Climate And Conflict
    Climate And Memory
    Climate History
    Climate Migration
    Climate Policy
    Climate Risks
    Climatology
    Columbian Exchange
    Conferences
    Dendrochronology
    Energy
    Environmental History
    Field Work
    Geoengineering
    Glaciology
    Global Warming
    Historical Climatology
    History Of Climate And Society (HCS)
    History Of Science
    Interdisciplinary Methodology
    IPCC
    Late Antique Little Ice Age
    Little Ice Age
    Maps
    Medieval
    Methodology
    Nuclear Power
    Paleoclimatology
    Pedagogy
    Politics Of Climate Change
    Resilience And Adaptation
    Teaching Climate
    Volcanoes
    Weather Modification

    RSS Feed

Powered by Create your own unique website with customizable templates.
  • Home
    • Archived Best of the Web
  • Features
    • Archived Features
  • Interviews
    • Climate History Podcast
  • Projects
  • Resources
    • Tools
    • Databases >
      • CLIWOC
    • Bibliography
    • Videos
    • Links
    • Tipping Points
  • Network
    • On Facebook
  • About
    • Our Team
    • Definitions