GG231 Lecture Notes - Lecture 7: Cryosphere, Axial Tilt, Eastern Canada
Document Summary
New forces on the natural system introduced by humans could be the leading factor. Can be linked to the amount of solar radiation on the earth. Milankovitch cycles: can be combined to determine net changes in radiation that any point on earth received through time: eccentricity (shape of earth orbit around the sun, obliquity (tilt, precession of the equinoxes (wobble) Cryosphere = the frozen part of the hydrosphere, comprising snow, sea and glacier ice and permafrost. Glaciers advance when their budget is positive (climate cools or becomes wetter) and retreat when it is negative (climate warms or becomes drier). Most canadian cities especially in the south were covered with an ice sheet 1-2 km thick about. 16,000-20,000 years ago, 30 percent of the earth was covered. Today we live in the interglaciation called the holocene epoch which began about 11,600 years ago short term changes. 15 of the warmest years in record history have occurred since 1990 ocean circulation.
