Global Climate Change for Beginners Robert K. Kaufmann TERC July 10, 2007 http://www.bu.edu/cees/people/faculty/kaufmann/index.html

Climate vs. Weather Weather: Conditions on any given day The temperature in Boston today is 88oF Climate: Average conditions on any given day over The average temperature in Boston on this day is 82oF

15,000 Years of Temperature

1000 Years of Temperature

Instrumental Temperature Record

Heat Balance of Planet Earth

Changes in Out-Going Radiation

Radiative Forcing of Sulfur Emissions Direct Effect

The Heat Balance of Planet Earth SOx Ground

The Heat Balance of Planet Earth SOx Clouds Ground

From: Petit et al., Nature 399, 429 - 436 (1999 The Vostok Record From: Petit et al., Nature 399, 429 - 436 (1999

How Do Humans Affect Radiative Forcing?

Burning Fossil Fuels

Changing Land-Use Deforestation Chopping down trees releases carbon dioxide Increasing termite habitat methane emissions Agriculture Rice paddies--human swamps emit methane Livestock--Methane ‘burps’

Atmospheric Concentrations

Detection: Is Climate Changing?

Earlier Springs, Later Autumns

Melting Ice Shelves There's no evidence of any period in the last 12,000 years where there was open water in the area that has now been exposed," Dr. Scambos said. New York Times March 20, 2002

Ice Shelf Break-Up Feb 17, 2002 Jan 31 2002 The speed of it is staggering," said Dr. David Vaughan, a glaciologist at the British Antarctic Survey. Feb 23, 2002 March 5 New York Times March 20, 2002

Attribution: Are Humans Responsible for Increased Global Temperatures?

Model Results

Statistical Analysis of Historical Data

Wall Street Journal December 4, 1997 How Much Doubt Exists? Wall Street Journal December 4, 1997 “If rising carbon dioxide is the cause of rising temperatures, why didn’t it cause temperatures to rise from 1940 to 1970? “Trust me, the satellite data have been reanalyzed dozens of times,…they show much less warming than expected by theory

Remember Sulfur Aerosols!

Contamination Satellite Reconciliation

Climate Models: How, Where, and By How Much Will Climate Change?

Causes For Temperature Change Doubling of radiative forcing……………1.2oC Increased water vapor……….. ……….1.6oC Increase in clouds………………………..0.8oC Changes in surface albedo……………….0.4oC Other changes……………………………0.2oC Total change in temperature…………….4.2oC

Forecasts for Climate Change More frequent extreme high temperatures and less frequent extreme low temperatures. Night-time low temperatures generally increase more than daytime highs, reducing diurnal temperature range. Decreased daily winter temperature variability and increased summer variability in mid-latitude N hemisphere Mid-continental summer drying due to precipitation not keeping up with temperature & evaporation Intensity of precipitation events increases.

Climate change impacts on the environment & economy Change in Sea Level Impact on agriculture Impact on Biomes

Changes in Sea Level Melting of glaciers and polar ice Thermal expansion of water

Eastern US 11.8 Thousand Years Ago

Eastern US 5 Meter Sea Level Rise

Eastern US 50 Meter Sea Level Rise

Impacts on Agriculture Benefits Costs Longer growing season Mid Continent Drying CO2 Fertilization Warmer nights Water use efficiency

Can Biomes Migrate in Time?

Climate Change & Extinction Climate change scenario Migration rate Minimum Middle High Universal dispersal 9-13 15-20 21-32 No dispersal 22-31 26-37 38-52 I’ve chosen region for a number of reasons. First, the Delta exemplifies China’s unparalleled economic growth. For the period 1988 to 1996, real GDP for counties in the delta increased by 350-550%. Second, the Delta is a major agricultural region. The semi-tropical monsoon climate combined with fertile alluvial soils makes the Delta a national leader in the production of lychees, bananas, pond fish, and sugar cane. This is important because conversion of agricultural lands in the delta will have impacts beyond the immediate region. Third, Delta is home to SEZs which are designated regions where the government can test and evaluate different market-based economic policies. And finally, the geographic proximity to Hong Kong and the cultural ties to overseas Chinese investors provides the region with constant access to capital flows and technological innovations. Thomas et al, 2004 Nature 427:145-148.

The Policy Debate Should anything be done? How much should emissions/concentrations be reduced? How should reductions be accomplished?

Should Anything Be Done? Is society emitting the optimal level of greenhouse gases and sulfur? No Emitters do not pay for any of the damage associated with global climate change

What information would society like to have ? How Much Should be Done? What information would society like to have ? What is the economic value of the damage (and benefits) associated with global climate change? What are the costs associated with reducing emissions of greenhouse gases and/or removing greenhouse gases from the environment?

The Kyoto Protocol

Implementing Reductions Command & Control Efficiency standards Mandatory reductions in energy use Market Based Mechanisms Carbon taxes Tradable permits

Tradable Permits

Carbon Offsets Commercial providers Boston-Orland round trip 2,243 miles Emissions 1,009 pounds carbon $9.95 in Offsets Offsets reduce emissions elsewhere

Shameless (but proud) Plug