We may have more on his essay later, but for right now I present his excellent timeline cartoon, that includes Earth’s obliquity and temperature over the last 20,000 years. The last major advance of glacial ice peaked about 18,000 years ago and since that time the ice has generally been retreating although with some short-term interruptions (See Graph above). Global Temperature Variation Over the Last 10,000 Years This graph’s title states that it is showing “global temperature variation” yet it is only showing Greenland glacier summit temperature which is a high altitude local proxy and not reconstructed global temperature. The following illustrative image, created by Robert Rohde, helps describe temperature variations since the end of the last glacial stage: The forcings that drove the glacial cycles, and that drove our last deglaciation (~10000 years ago) reached a peak at the Holocene Climate Optimum, about 8,000 years ago. Today’s infographic from XKCD shows the Earth’s temperature since the last ice age glaciation, which was 22,000 years ago. Changes in Earth’s obliquity and thus solar insolation angles is believed to be the main driver of long term climate change, initiating and ending ice ages. Although some of the details are different, they all show several similar trends in Northern Hemisphere climate: relative warmth before the 14th century followed by cold periods between the 15th and early 19th centuries.
Simulations of the last 1,000 years have been completed with several different models. For most of the past 10,000 years, global average temperature has remained relatively stable and low compared to earlier hothouse conditions in our planet's history. Earth’s Temperature Over 22,000 Years. It was around this time that there were vast ice sheets covering North America, northern Europe, and Asia. Temperature chart for the last 11,000 years posted by Jason Kottke Sep 16, 2013 For the first time, researchers have put together all the climate data they have (from ice cores, coral, sediment drilling) into one chart that shows the “global temperature reconstruction for the last 11,000 years”: