Spurred by all the fuss over “Climate Change” I decided to start learning more about Earth’s climate history a few years ago and the more I studied the more intriguing I found it to be. One of the more interesting proxies for past climate is the oxygen isotope ratio analysis of glacial ice cores and ocean sediment cores. Some of the deepest and thus oldest ice cores have been analyzed from Greenland and Antarctica. Even older stretches are covered by ocean sediment cores. To me it is very reassuring how well the patterns from ice cores and ocean sediments match, especially considering that the ice cores are from polar regions while the ocean sediment cores are mainly from tropical and subtropical areas. However, it is obvious that in trying to project the oxygen isotope analyses to reconstruct global temperature there is a lot of uncertainty about the magnitude as can be seen in the graph below (click for larger image).
Regardless of which projection may be the most accurate, they all show that much of the last 500,000 years the Earth’s climate has been dominated by lengthy glacial periods with only relatively brief warm interglacial periods. We happen to be very fortunate to be in one of the interglacial periods, but how much longer will it last?
In my next post I will investigate adjusting these different reconstructions to better match each other.