The Carbon Cycle: Ocean and Biosphere
Class #14 (Fri., Feb 10)
Reading:
Required Reading (everyone):
- Understanding the Forecast, Ch. 8, pp. 89–97.
Reading Notes:
- Know the different forms carbon takes in the earth system: CO2 and
organic gases in the atmosphere; dissolved inorganic carbon in the
hydrosphere; solid organic and inorganic matter in the
lithosphere (what’s the difference between organic and inorganic? What are
dominant forms that each takes in the lithosphere?); and living organic
carbon in the biosphere.
- What are oxidation and reduction and how do they affect organic and
inorganic carbon?
- Focus intently on Fig. 8.1: get a feel for the size of each reservoir and the
magnitude of flux between the different reservoirs. Don’t feel that you have
to memorize the numbers, but you should have a good feel for which are larger,
which are smaller, and a general sense of the range of sizes.
- What are the dominant mechanisms by which carbon moves from one reservoir to
another? Which processes are fast and which are slow?
- In Fig. 8-2, why are the annual wiggles in the atmospheric carbon
concentration so much bigger in Hawaii than in New Zealand?
- How might feedbacks in the carbon cycle destabilize the global climate?
- Try to get a rough feel for the orbital forcing of climate, but don’t stress
about the details. We’ll dig into this in much more depth when we look at
climates of the past, on
Feb. 22–24.
The key here is to understand that small variations in the earth’s orbit lead
to small forcings on the climate, which are dramatically amplified by a
positive feedback in the carbon cycle to produce the cycle of ice ages that
the earth experienced over the past 2 million years or so.
