NATS 101 Lecture 33 Climate Change (contŐd)

The Natural Greenhouse Effect: clear sky

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Global Warming Potential (GWP)

	Different gases has different warming potentials which are defined relative to the warming effect of CO2

Changing CO2 concentrations

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Increasing CO2 concentrations

Predictions of increased CO2 & Temperature

Missing Carbon Sink

	CO2 is accumulating in the atmosphere more slowly than expected (believe it or not)
	Based on our understanding of CO2 emissions and ocean and atmosphere uptake, there is a missing sink/uptake of about 25%

Ocean Carbon Uptake

Ocean Uptake of CO2

	SciAm article

The Oceans & Global Change

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Ocean Transport of Heat

3D ŇConveyor BeltÓ Concept

Potential Changes Related to the Ocean

Change in Thermohaline Circulation

Change in Ocean Chemistry

Ocean Acidification    (SciAm article)

	Currently ~1/3 of CO2 released by burning fossil fuels ends up in the ocean.
	Absorbed CO2 forms carbonic acid in seawater, lowering the slightly alkaline pH level, changing the balance of carbonate & bicarbonate ions.
	Shift toward acidity & ensuing changes in ocean chemistry, make it more difficult for creatures to build hard parts out of calcium carbonate.
	Decline in pH thus threatens a variety of organisms, including corals, which provide one of the richest habitats on earth.
	Within a century, Southern Ocean surface will be corrosive to shells of tiny snails key in the marine food chain within this highly productive zone.

Sea level is rising:

Observed Ocean Warming

	Most oceans are warming
	Figures from Hansen et al 2006

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Surface melt on Greenland

Greenland ice mass budget

Snow cover and Arctic sea ice are decreasing

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Land surface temperatures are rising faster than SSTs

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Water vapor increase at higher temperatures

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