The Changing Climate
Chapter 14

 

 

 

Time history of atmospheric CO2 from 800,000 years BP to January 2012.

 

What Do Scientists Do?

 

 

The Changing Climate

 

Male, capital city of the Maldives

 

What is climate change?

 

Global warming

 

The sun and atmosphere keep Earth warm

 

Greenhouse gasses warm the lower atmosphere

 

Carbon dioxide (CO2) is of primary concern

 

 

What caused levels of CO2 to increase?

 

 

Other greenhouse gasses add to warming

 

US emissions of major greenhouse gasses

 

 

Feedback complicates our predictions

 

 

Most aerosols exert a cooling effect

 

Radiative forcing expresses change in energy

 

 

Milankovitch cycles influence climate

 

Orbital Variations

 

 

 

 

Solar output and ocean absorption influence climate

 

Ocean circulation influences climate

 

Direct measurements tell us about the present

 

Proxy indicators tell us about the past

 

Ice cores from Antarctica

 

 

More proxy indicators

 

Models help us predict the future

Models simulate climate processes to accurately predict climate change

Java-based Climate Model

 

 

Results from three simulations

 

 

The IPCC's fourth assessment report (2007)

 

The IPCC's fourth assessment report (2007)

 

 

Temperatures continue to rise

      

 

The future will be hotter

 

 

Temperatures will rise globally

Projected increases in surface temperature
for 2090-2099 relative to 1990-1999

 

 

Precipitation is changing too

Projected changes in precipitation

Precipitation will increase at high latitudes
and decrease at low and middle latitudes

 

 

Melting snow and ice

 

Worldwide, glaciers are melting rapidly

 

 

 

Rising sea levels

 

 

Coastal areas will flood

 

 

Rising sea levels will devastate coasts

 

Coral reefs are threatened

 

Climate change affects organisms and ecosystems

 

 

Climate change affects people

 

 

Heat waves will increase

 

 

 

Climate change affects economies

 

Impacts will vary regionally

 

Impacts of climate change

      

 

 

Impacts of climate change will vary

 

 

 

Predictions from two climate models

By 2050, Illinois will have a climate like
Missouri's and by 2090, it will have a
climate like Louisiana

 

 

Are we responsible for climate change?

 

 

The debate over climate change is over

 

"Climategate"

 

 

Shall we pursue mitigation or adaptation?

 

 

We need both adaptation and mitigation

The faster we reduce our emissions,
the less we will alter the climate

 

 

 

Electricity generation

 

 

Sources of electricity

 

Market mechanisms address climate change

 

 

 

Cap-and-trade emissions trading programs

 

Carbon taxes are another option

 

Carbon offsets are popular