The Current Interglacial Holocene

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The Current Interglacial (Holocene)
AOS 528, 11/29/07
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The Holocene

• Approximately 11,600 years ago to the present
• Increasingly modified by human activities
• Land use causes local climate effects
• Altered atmospheric composition causes global
  climate effects
• Records of long and short-term climate change
• Alpine glaciers
• Monsoons
• El Niño-Southern Oscillation

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Holocene Climate Forcings

• Orbital Variations
• Volcanic eruptions
• Changes in amplitude and occurrence
• Solar luminosity variations
• Much study (Particularly at NASA. Why?),
• Minimal effects
• Greenhouse gas concentrations
• Waning Ice Sheets
• Effects on albedo and atmospheric circulation

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Holocene Climate Forcings

• Orbital Variations
• Volcanic eruptions
• Changes in amplitude and occurrence
• Solar luminosity variations
• Much study (Particularly at NASA. Why?),
• Minimal effects
• Greenhouse gas concentrations
• Waning Ice Sheets
• Effects on albedo and atmospheric circulation

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The Holocene and Orbital Variations
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N. HEM. SUMMER INSOLATION
Incident Shortwave Radiation over Land, Ocean and
Globally
Incident Shortwave Radiation at 10Kyr, 6Kyr, and
0Kyr BP
Specified SST
Predicted SST
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INSOLATION and PRECIP EFFECTS
Summer Radiation (W/m2)
NW African Climate
Simulated Precipitation Change in centimeters
deMenocal et al., Science, 2000
www.cgd.ucar.edu/asr/asr03/ccr/index.html
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INSOLATION and PRECIP EFFECTS
Effect of Insolation on the African Monsoon
Source PMIP (Paleoclimate Model Intercomparison
Project) and the Global Lake Status Database,
(GLSDB Kohfeld and Harrison, 2000, Harrison et
al., 2003)
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Holocene Greenhouse Gases

• Known from ice cores
• Carbon Dioxide (CO2)
• 10-8kyr decreases 7ppm
• 8kyr-preindustrial increases 20ppm
• Methane (CH4)
• 10-6kyr decreases 150ppb
• 6-preindustrial increases 150ppb
• Nitrous Oxide (N2O)
• 10-8kyr decreases 10ppb
• 8-2kyr increases 10ppb

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Holocene Greenhouse Gas Forcing

• Total combined Holocene greenhouse gas forcing
  was about 0.5 W/m2

T

• CO2 0.4 W/m2
• N2OCH4 0.1 W/m2

Flueckiger et al., 2002
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The Anthropocene?

• Why were GHG concentrations varying before the
  industrial age?

Ruddiman, 2005
http//www.realclimate.org/index.php/archives/2005
/12/early-anthropocene-hyppothesis/
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Term Paper Instructions

• 3. Required sections
• Introduction
• Model Description
• Experiment Description
• Results
• Discussion
• (interpret and contextualize results)
• Conclusions
• (and Future Work)

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Term Paper Instructions

• Due dates December 8th and 13th (midnight)
• Term Paper Instructions
• 10-15 pages, single-spaced including
• Title page
• Figures
• References (at least 5)
• 1 inch margins, 12pt font
• All figures must have captions
• Each person must contribute some material

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Term Papers Due Dec. 13th
Presentations Thursday, December 6th (during
class) Group 2 Phillips, Schiferl The
Effectiveness of the Kyoto Protocol Group 7
Schmidt, Bruskewitz, Serwe Title? Group 8
Schuh, Moore, Olson Effects of Global Warming
on Agriculture Production in the Midwest Group 9
Kirchner, Shewczyk, Welhouse Global Climate
Change's Effects On Agriculture Group 10
Franklin, Obbink, Orland The Effects of Orbital
Forcings During Mid-Pliocene Global Warming
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Term Papers Due Dec. 8th
Presentations Thursday, December 20th
(1005am) Group 1 Lubcaynka, Moua,
Propheter US and China's Affect on Global
Warming Group 3 Caruso, Maloney,
Schmelzer Title? Group 4 Schreiber,
Brown "Peak Oil" Predictions and Their Effect on
Future Warming Group 5 Asuma, Caves, Koch A
Comparison of Global Climate Effects Due to
Varying Rates of Methane Introduction Group 6
Marsicek, Ronnei, McCarville Using Drought
Index to Analyze Potential Impacts on the
Tropical Rainforest By Increasing CO2 and Solar
Luminosity Group 11 Hladish, Kampa A Potential
Glacial Maximum in the Future?