Lecture 27: Climate Change, Ecology and Society.

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Lecture 27 Climate Change, Ecology and
Society.  

• By the end of this lecture you should be able to
• Describe the projected effects of the rapid
  change in climate driven by human alteration of
  the C cycle.
• Discuss potential feedbacks that may accelerate
  global warming.
• Concepts and terms boreal forest and the arctic
•  Discuss the Niche concept and how it is used to
  construct the distribution of future ecosystems.
•  Describe how paleoecology is used to understand
  the relationship between climate and ecosystem
  function.

• Describe how ancient soils and fossils are dated.
• Concepts and terms 14C, half life, radioactive
  decay
• Discuss basic principles of dendroecology.
• Concepts and terms  tree rings
• Describe how small changes in climate may alter
  human affairs.
• Reference Readings
• http//www.fs.fed.us/ne/delaware/atlas/Launch
  the atlas
• http//tree.ltrr.arizona.edu/

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Variations of the Earths Surface Temperature on
Two Time Scales

• relative to 1961-1990 average

Source IPCC TAR 2001
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Projected Changes in Annual Temperatures for the
2050s
The projected change is compared to the present
day with a 1 increase per year in equivalent CO2
Source The Met Office. Hadley Center for Climate
Prediction and Research
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Projected Changes in Annual Precipitation for the
2050s
The projected change is compared to the present
day with a 1 increase per year in equivalent CO2
Source The Met Office. Hadley Center for Climate
Prediction and Research
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• Direct effect
• Feedback

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Historical Trends in Lake and River Ice Covering
the Northern Hemisphere

• freeze date gt 5.8 days / 100 yrs
• thaw date lt 6.5 days / 100 yrs
• temperature change 1.2oC / 100 yrs
• J.J. Magnuson et al. Science 289, 1743-1746 (2000)

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What are these??? Water Use Efficiency
Photosynthesis/Transpiration
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Niche all resources required by a species
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Present
2X CO2
http//www.fs.fed.us/ne/delaware/atlas/Launch
the atlas
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http//www.fs.fed.us/ne/delaware/atlas/s131f.html
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http//www.fs.fed.us/ne/delaware/atlas/web_atlas.h
tmlAllSpp
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Natural Experiments of the Past
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Annual layers radiocarbon (14C) technique
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Carbon 14 Dating
14N n gt 14C p 14C gt 14N b T1/2 5563
years, after 10 half lives undetectable. T ln
(Nf/No)/(-0.69)T1/2
http//www.c14dating.com/index.html
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http//www.museum.state.il.us/muslink/forest/htmls
/an_nelson.html
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Earth's oldest living inhabitant at 4,767 years,
White-Inyo mountain range of California.
Bristlecone pine ghost
http//www.sonic.net/bristlecone/Images.html
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Dendrochronology is the dating and study of
annual rings in trees.
http//tree.ltrr.arizona.edu/dendrochronology.html
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Little Ice Age 1550-1850 (coldest-early 1800s)
Global mean temperature decreases lt 1 oC
Crop failure in Scotland
10 of Scotland migrates to Ulster (N. Ireland)
Massive population growth in Ireland Dependence
on one crop
1845. Potato Blight originates in Peru. Crop
failure - 1 million die in Ireland
Rapid warming at end of LIA warm and wet in
Ireland
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Extreme Events
Judgmental estimates of confidence by IPCC very
likely - 90-99 chance, likely - 66-90 chance.
Source IPCC TAR 2001