ENVR 200 Lecture Notes - Lecture 15: Primary Production, Permafrost

• School: McGill University
• Department: Environment
• Course: ENVR 200
• Professor: George Mc Court

Document Summary

Strong correlation between temperature and ghg concentration in the atmosphere. Ghgs include water vapour, co2, methane, nitrous oxide, cfcs and ozone. Different ghgs have different radioactive forcings and residence times. Natural inputs include volcanism, respiration, decay and metamorphism. Anthropogenic inputs include fossil fuels, land use changes and cement production. Co2 residence time is 7 years in steady state. Residence time is affected by the removal of co2 into the oceans and terrestrial biomes. About half of the extra co2 added is sunk in terrestrial ecosystems and oceans. Ocean mixing is very slow, and temperature variations affect co2 solubility. Currently the ocean is a net sink, but if temperature rises, this could be reversed. Terrestrial ecosystems store carbon in soil and vegetation. Residence time is 52 years for excess co2. Is 21 times more potent than co2 as a ghg. Methane is emitted from oceans and the earth.