1. When large meteors, or asteroids, collide with planets, they eject dust and debris that can cause extended darkness, global fires, acid rain, ozone loss and even tsunamis. The result of these extraterrestrial catastrophes can be a cooling of global climate and widespread extinctions. Click on the image to learn more about the end of the age of the dinosaurs due to an ancient asteroid impact.

2. Volcanic eruptions have obvious local effects on weather and climate and may also produce extended effects on global climate. Two significant eruptions were Krakatoa in in 1883 and Tambora in 1815 which both occurred in the southern hemisphere but affected ensuing seasons in the northern hemisphere and increased atmospheric sulpher content worldwide. Click on the image for a graph depicting annual acidity data documented in ice core data from central Greenland .

3. Milankovitch's theories were verified by trace gas concentrations in the Vostok ice core. Click on the image to compare a graph of this data with past Earth Orbits.