9.3 The Greenhouse Effect

What does darker, lower albedo surfaces do?

absorb sunlight & release infrared radiation (warmth)

What would happen without the greenhouse effect?

earth would be too cold to support life

Rank the GHGs in the order of IR absorption in relation to CO2 (least to greatest)

methane (CH4) —> nitrous oxide (N2O) —> CFCs

How does the greenhouse effect work?

1. solar radiation (light waves like UV & visible light) strike earth's surface heating it 2. earth's surface release infrared radiation 3. GHGs absorbed infrared radiation & radiate it into space and back toward Earth 4. the portion coming back to earth is the "greenhouse effect"

What percent of solar radiation is absorbed by ________ & ________ and radiated into space & down to Earth?

19% by atm. & clouds

What percent of solar radiation is reflected back into space by _______ & ______?

26% by clouds & atm.

What are the most important GHGs? (4/5)

CO2, methane (CH4), ,nitrous oxide (N2O), CFCs/HCFCs/HFCs water vapor (H2O) *technically a GHG by def but it doesn't drive atm temp change

Does all incoming solar radiation reach earth's surface?

No

What happens to the rest of the solar radiation?

reaches Earth's surface where it can be absorbed or reflected (depends on albedo of surface it strikes)

What does lighter, higher albedo surfaces do?

reflect sunlight directly back into space or into clouds/GHGs that absorb it

What can the measure of how much a given molecule of gas contribute to? What factors is this based on? (2)

the warming of the atm. over a 100 yr period, relative to CO2 1. residence time: how long mol stays in atm. 2. infrared absorption: how well the gas absorbs & radiates infrared radiation (IR)

What do the gases in earths's atm do?

trap heat from the sun & radiate it back to earth