Climate feedbacks for global warming
Review of last lecture Mean state: The two basic regions of SST? Which region has stronger rainfall? What is the Walker circulation? Two types of ocean upwelling Mean state: ocean-atmosphere feedback ENSO: Which region has warm SST anomaly during El Nino? 4- year period. Existing ENSO theories AMO and thermohaline circulation
Global connections
The most common atmospheric circulation structure L H H L Heating Cooling or No Heating Imbalance of heating Imbalance of temperature Imbalance of pressure Wind Radiation Convection Conduction Latent/Sensible Biosphere Land/Ocean/Ice/Stra tosphere Feedback Greenhouse Gases Pollution Clouds Precipitation (Latent heat)
How do human activities change the global climate? Human beings are changing the global climate system in three different ways: Change land cover (deforestation and afforestation) Release or cleanse pollutants (aerosols) Release or cleanse greenhouse gases
Observed Change in Global Temperature: Significant warming
Global map of temperature change: Largest warming in Arctic (“Arctic amplification”) Larger warming over land than ocean
Projected Change in Global Temperature: Significant warming
The spread comes from uncertainties in climate feedbacks
Main climate feedbacks for global warming Ice albedo Lapse rate (temperature) Water vapor Cloud Aerosol Carbon cycle
Ice albedo feedback
Lapse rate feedback Surface Tropopaus e Surface warming Same lapse rate Larger Longwave flux Warming of whole troposphere Cooling down of surface temperature
Water vapor feedback
Cloud feedback Stronger warming effect Stronger cooling effect
Aerosol feedback
Video: Carbon Cycle yer_detailpage&v=U3SZKJVKRxQhttp:// yer_detailpage&v=U3SZKJVKRxQ
Global carbon cycle
Carbon cycle feedback
Carbon cycle feedback Example 1: Permafrost thaw
Carbon cycle feedback Example 2: Biosphere
Carbon cycle feedback sources
Feedback strength in climate models Water vaporCloudAlbedoLapse rate
Projected Change in Global Mean Temperature
Abrupt climate change and tipping point – Lesson from Earth’s climate history
Termination of the Younger Dryas cold event and last ice age 11,600 years ago
Abrupt climate change and history/politics - Collapse of Maya civilization and Chinese ancient dynasties Drought s
Bifurcation and tipping point
Examples of tipping points
Interactions among tipping points
Summary Large spread in projected temperature change comes from uncertainties in climate feedbacks Main climate feedbacks for global warming: albedo, lapse rate, water vapor, cloud, aerosol, carbon cycle Feedback strength in climate models: cloud feedback causes the largest uncertainty Past abrupt climate change Tipping points Future abrupt climate change
Works cited full.jpghttp:// full.jpg ity.htmlhttp:// ity.html thttp://sitemaker.umich.edu/section2_group1/arctic_issues__permafros t resolution-images-google-earthhttp:// resolution-images-google-earth Warming/Global-Warming-is-Causing-Extreme- Weather/Wildfires.aspxhttp:// Warming/Global-Warming-is-Causing-Extreme- Weather/Wildfires.aspx severity-even-in-a-warmer-climate/ severity-even-in-a-warmer-climate/
Work cited remains-strong/ remains-strong/ http:// generating-industries/Post-Combustion-Carbon-Capture.aspxhttp:// generating-industries/Post-Combustion-Carbon-Capture.aspx climate-tipping-point/ climate-tipping-point/