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

HeatingCoolingor No Heating

Imbalance of heating Imbalance of temperature Imbalance of pressure Wind

Radiation Convection Conduction

Latent/Sensible

BiosphereLand/Ocean/Ice/

Stratosphere 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

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

Tropopause

Surface warming

Same lapse rate

Larger Longwave flux

Warming of whole troposphere

Cooling down of surface temperature

Water vapor feedback

Cloud feedback

Strongerwarming effect

Stronger cooling effect

Aerosol feedback

Video: Carbon Cycle

• http://www.youtube.com/watch?feature=player_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 vapor Cloud Albedo Lapse 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

Droughts

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• http://www.jpl.nasa.gov/images/earth/20100325/atlantic20100325-full

.jpg

• http://www.nasa.gov/centers/goddard/news/topstory/2004/0315humidity.html

• http://sitemaker.umich.edu/section2_group1/arctic_issues__permafrost

• http://www.all-creatures.org/hope/gw/02_Arctic-Antarctic.htm

• http://www.fedre.org/en/content/global-permafrost-zones-high-resolution-images-google-earth

• http://www.onlyzerocarbon.org/arctic_feedback.html

• https://www.marietta.edu/~biol/biomes/tropdry.htm

• http://www.nwf.org/Wildlife/Threats-to-Wildlife/Global-Warming/Global-Warming-is-Causing-Extreme-Weather/Wildfires.aspx

• http://www.opb.org/news/blog/ecotrope/qa-how-to-reduce-wildfire-severity-even-in-a-warmer-climate/

Work cited• http://www.ncdc.noaa.gov/paleo/ctl/abrupt.html

• http://intercongreen.com/2010/03/15/green-building-ebbs-slightly-in-recession-but-sentiment-remains-strong/

• http://nimbuseco.com/2013/01/deforestation-and-pollution-facts/

• http://greenbalkans.org/category.php?language=en_EN&cat_id=63

• http://www.nrcs.usda.gov/wps/portal/nrcs/detail/ia/newsroom/releases/?cid=nrcs142p2_011847

• http://www.csiro.au/en/Portals/Multimedia/On-the-record/Megan-Clark-presentation-20090526-generating-industries/Post-Combustion-Carbon-Capture.aspx

• http://economistsview.typepad.com/economistsview/2005/09/the_consumer_dr.html

• http://nca2009.globalchange.gov/human-health

• http://yosemite.epa.gov/ee/epa/eerm.nsf/vwAN/EE-0564-112.pdf/$file/EE-0564-112.pdf

• http://livinggreenmag.com/2012/06/13/climate-change/scientists-warn-that-earth-is-close-to-climate-tipping-point/

• http://www.cnn.com/2013/05/29/opinion/mystreet-digital-anthropology/

• http://commons.wikimedia.org/wiki/File:World-airline-routemap-2009.png