Climate Change. The story line Earth’s energy budget More energy? Warming? What else? What about the future? So what?

Climate Change

The story line

• Earth’s energy budget

• More energy?

• Warming?

• What else?

• What about the future?

• So what?

The climate system

Involves the exchange of energy and moisture that occur among the:

• Atmosphere• Hydrosphere• Solid Earth• Biosphere• Cryosphere (ice and snow)

Natural causes for climate change

• Greenhouse gases

• Solar variation– Long term increase– 11-year cycle (0.08%)

• Orbital variations

• Volcanism

• Plate tectonics

Human causes for climate change

• Long-lived greenhouse gases– CO2, Methane, N2O

• Aerosols

• Land use

• Aviation contrails

More Energy?

Warming yet?

What else?

Larsen B ice shelf broken up

Jan 31, 2002 March 7, 2002

Contributions to Sea Level RiseContributions to Sea Level Rise

What about the future?

How good are climate models?

• Simple climate model

• Earth system models of intermediate complexity (EMICs)

• Atmosphere-ocean global circulation models (AOGCMs)

Temperature increase for different levels of CO2 concentration

IPCC SRES Scenarios

• A – Economic growth– A1: more integrated and convergent world

with stabilizing population at 9 billion– A2: more divided and fragmented world with

increasing population

• B – Ecologically friendly– B1: more integrated world with stabilizing

population– B2: more divided and fragmented world with

slower rate of population growth

Emission Scenarios

Projected global surface warming and sea level rise at 2100

So what?

A tale of an island

Risk Zones

0 - 3 ft.

3 - 6 ft.

6 - 9 ft.

above 9 ft.

RoadsLimited Access

Highways

Secondary Roads

Other

Highway Ramp

Cape May County, New Jersey

Risk Zones

0 ft. and below

0-3 ft.

3-6 ft.

6-9 ft.

above 9 ft.

open water

Roads

Limited Access

Highways

Secondary Roads

Other

Highway Ramp

Atlantic County, New Jersey

Mid-Atlantic States: MA-VA

• About 1,000 square miles of land area lies below 3 feet

• Within this area, about 70 square miles are developed land

• About 388 thousand people live in this high risk zone.

• Nearly 3,000 miles of roads are exposed to such high risk of inundation.

• Southern states have more area, people and facilities lying in high risk zones because of gentler terrain and more development along the coast

• CARA website

Do Warmer Seas mean worse Hurricanes?

Sea surface temperature of the Gulf of Mexico, 8/28/2005

Total power dissipated by tropical cyclones compared to September North Atlantic sea surface temperature

(Emanuel, 2005)

Disruption of ocean circulation?

Shifts in Agriculture

Extreme Weather Events

Human Health• More heat-related deaths• Spread of tropical

diseases into temperate areas

• Increase of vector-borne diseases: malaria, west Niles, Lyme disease

• Disruption of water and food supply

Species distribution and diversity