The Earth and its atmosphere

The large H 2 O greenhouse effect is controlled by temperature – H 2 O saturation doubles with every 10°C Increase As a result It is concentrated in the lower atmosphere of the tropics The most potent greenhouse gas is H 2 O - vapor

The CO 2 greenhouse gas effect is concentrated in the polar regions ! ! ! CO 2 is evenly distributed throughout the atmosphere Particularly in the Arctic !

John Cook, from IGPP 2007 data; ~93% to oceans continues (NOAA/NODC, 2012) Melting ice absorbs ~2% Only ~2% stays in atmosphere ~2% warms the land

Oceans, m depth Oceans, m depth Atmosphere + land + ice melting Change in heat content, (NOAA 2012 data, Nuccitelli et al plot) 5-year moving averages Joules ( Increasing heat, not shown, goes deeper than 2000 m)

m 3 (95 cm x 95 cm x 95 cm)

10 o C = (50 o F) 7.8 cc 20 o C = (68 o F) 15 cc 30 o C = (86 o F) 27.7 cc 40 o C = (104 o F) o C +1 o C = 8% increase in vapor

Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles 41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma5.0Ma 0 When CO 2 levels get below ~ ppm Orbital parameters become more important than CO 2 the last time inferred temperatures will have been this high – once equilibrium is reached, will have been 3-5 million years ago or more * we are now about here

China has the largest fossil fuel emissions today. However, climate change is driven by cumulative emissions, so developed nations, especially the U.S., have greatest responsibility.