Addition of carbon dioxide and other trace gases to the atmosphere are likely contributing to global climate change Trace gases include methane, nitrous oxide, and CFCs The carbon cycle Carbon dioxide levels in atmosphere 280 ppm (parts per million) before the industrial revolution 370 ppm in 2000 should be higher – something is removing some of the carbon Geochemical cycles – how they work Geochemical reservoirs Residence time Chemical reactions Transport across interfaces Example – calcium cycle Calcium enters reservoirs through rivers of the world and dust Sedimentation of calcium carbonate Calcium residence time is long (600,000 years) Earth’s carbon budget
Air-sea gas exchange Photosynthesis and respiration in the terrestrial biosphere Dissolved organic carbon Carbonate weathering and precipitation Human perturbations of the carbon cycle Humans add carbon to the atmosphere Plants and air-sea gas exchange removes some of it There is a net annual increase Human fingerprints of global change 20 th century warming fossil fuel burning Some possible consequences of Global Warming Due to complexity of the climate system, not all future shifts can be foreseen Some unexpected changes in climate are possible A constant state of change in very likely
You've reached the end of your free preview.
Want to read all 8 pages?
- Spring '07
- Climate Change, global climate change, infrared radiation, Airsea gas exchange