GEOL 213 Lecture Notes - Lecture 28: Jet Stream, Himalayas, Radiocarbon Dating
Document Summary
Variations in both solar input and redistribution of heat within the climate system lead to natural variations in local climate. These variations range in time scale from millions of years (plate tectonics) to thousands of years (orbital variations) to decades/year (internal heat transfer via wind & water currents). 10 myr ago water could easily flow between atlantic & pacific. That stopped ~5 myrago and today no water flows between oceans near the equator. Current deep ocean current system did not become fully established until after closing of isthmus of. Panama; this coincides with start of n. hemisphere glaciation. Changes in earth"s orbit around the sun change both the total solar energy and its distribution across the planet. These changes appear to drive the advance and retreat of ice age glaciation over the past ~2-3 million years. Periodic advances and retreats of glaciers (left) over the past 2-3 million years.