1. Greenhouse Effect
Presented By:
Janet Fang
Sam Atwood
EESC W4400

2. Earth’s Energy Balance
Thermal Equilibrium
Energy in = Energy out
Radiative Heat Transfer
F=T4
Radiation
Reflected and absorbed by surface and atmosphere
Atmosphere reradiates to surface causing warming
33°C higher than with no atmosphere
Benin

3. Source: IPCC Climate change 2001 - Synthesis report
Greenhouse Gases
GHGs
Water Vapor
Carbon Dioxide
Ozone, CH4, N20, SO2, CFCs
Atmospheric GHG concentration changes energy absorbed and reradiated to surface
Surface Temperature change
Thermal Inertia
GHG concentrations change
Takes time to transition between equilibrium states due to heat capacity of the oceans
Current Earth System is not in an equilibrium state
Source: IPCC Climate change Synthesis report

4. Source: IPCC Climate change 2001 - Synthesis report
Greenhouse Effects
Climate Sensitivity
Temperature change with doubling of atmospheric CO2
1.5 to 4.5 ºC
Humans increasing GHGs
Models and Theories predict Global Warming effects
Thermal Inertia: 25 to 50 years to reach 60% of a total temperature change with a change in GHG concentration
Source: IPCC Climate change Synthesis report

5. Take Home Points Questions?
1) Greenhouse Gases in the atmosphere have a warming effect on surface temperatures
2) Rapid changes in GHGs take time to alter surface temperatures
3) Humans are GHG concentrations, which can cause Global Warming
270 ppm increased to 380 ppm over the last 150 years
0.6 to 0.9 °C increase in temperature in the same time period
Questions?