ENVR 200 Lecture Notes - Lecture 13: Last Glacial Maximum, Milankovitch Cycles, Solar Irradiance

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

Document Summary

More detailed record over the last 2 million years. Better time resolution, fossil/rock records, ice cores, better proxy data techniques. Glaciations and interglaciations have formed a fairly consistent rhythm. O16 is more common and lighter (evaporates more easily) than o18. O18 condenses and cools more quickly than o16. Thus, more o18 precipitates earlier, then o16 precipitates in higher latitudes. When ice melts, o16 is added back into the oceans. In glacial periods, glacial ice accumulates o16, without returning it to the ocean. Air bubbles in the ice have the air composition of when they were trapped. Higher co2 and methane correlates to higher temperature. Sediments including calcium carbonate in shells contain o16 or o18. Affect insolation, the amount of energy entering the earth. Affect feedbacks like ice-albedo feedback and the biological pump. Eccentricity is the changing shape of the earth"s orbit (100,000y)