8. past million years

8. past million years - Ante-preshow: Respect the Mountain...

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Ante-preshow: Respect the Mountain
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Preshow: Part of a “natural cycle”?
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past million years (climate proxy) Last 1000 years Last million years: cores, oxygen isotopes, Milankovitch
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WTF is a temperature anomaly? ’”Anomaly” means departure from a baseline average. Example The average annual temperature in New Jersey from 1971-2000 is 52.65 °F = 11.5°C The average temperature in NJ in 2010 was 54.8 °F = 12.6° C The anomaly for 2010 for NJ was +1.1°C or 2°F To get the U.S. anomaly, average the 144 stations in U.S. Global Historical Climate Network (GHCN)
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Schedule change Recitation will meet two consecutive weeks on Feb. 22/23 and March 1/3 Catch up and review lecture March 1 Exam still March 8: 40% multiple choice f/ clickers, 40% fill in blanks, 20% (2 of 3) essay
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Clip from Inconvenient Truth : VP Gore on Arctic Warming
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Warmer global T Snow cover loss Melting mtn glaciers Longer growing season Sea ice loss Increased cloud cover Sea level rise Warming is indicated by more than Temperature
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Evidence for Global Warming
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Proxy data and Temperature of the last 1000 years: Hockey stick hokum? Michael Mann Then of UVa now a Nittany Lion
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Reconstructions of Past Climate: Tree rings http://www.ltrr.arizona.edu/ lorim/good.html Dendroclimatology: relationships between annual tree growth and climate Growth rings affected by many aspects of the microclimate: sunshine, precipitation, temperature, wind speed and humidity Only for trees growing near the extremities of their ecological amplitude, where they may be subject to considerable climatic stresses, is it likely that climate will be a limiting factor cross-dating the individual series after the removal of age effects by standardization
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Reconstructions of Past Climate: Tree rings http://www.ltrr.arizona.edu/ lorim/good.html Dendroclimatology: relationships between annual tree growth and climate Calibrate the tree ring temperature estimates to real temperature (thermometer) data ( and Can get climate information back a few 1000 years
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Reconstructions of Past Climate: Tree rings Tree ring data are one of most important proxies for climate prior to instrument (thermometer) records because they go back 1000’s of years by splicing individual trees and are virtually global in distribution IPCC, AR4, 2007
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Law Dome Greenland Ice cores provide both measurements of temperature using isotopes and gases including CO2 records and are arguably the best paleoclimate records with annual resolution However, they are restricted to a few mountain glacier (e.g., Andes, back a few 1000 years), Greenland (back 125,000 years), and Antarctica (back 800,000 years) Corals provide subannual resolution from isotope temperature measurement but are restricted to tropics and subtropics (warmer than 18°C)
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Reconstructions: boreholes Sinceheat transfer through the ground is slow, temperature measurements at a series of different depths down the
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8. past million years - Ante-preshow: Respect the Mountain...

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