Lewis Page offers a summary of an article in Science on temperature variations in antartic ice cores over the past 14,000 years. In summary the region has been much colder and much warmer than the present over that stretch of time. At least in that region of the earth the recent warming does not appear to be without precedent.
This graph also shows temperature variation in the antartic core for the past 400,000 years. It also shows temperature variations on a cyclic basis. Note that the recent carbon dioxide levels are higher than the typical peak of 280 ppm.
Globally carbon dioxide levels have risen considerably in the past 50 years with levels at 340 in the in the 1980's to levels around 385 in 2010. These carbon dioxide levels are similar to what I have measured in Minnesota over the past 24 years.
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| http://www.theregister.co.uk/2012/08/23/antarctic_peninsula_ice_core/ |
This graph also shows temperature variation in the antartic core for the past 400,000 years. It also shows temperature variations on a cyclic basis. Note that the recent carbon dioxide levels are higher than the typical peak of 280 ppm.
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| http://www.geol.umd.edu/~lsschlei/CoolGeologyLinks/Tectonics_Website/IceCoreData.JPG |
Globally carbon dioxide levels have risen considerably in the past 50 years with levels at 340 in the in the 1980's to levels around 385 in 2010. These carbon dioxide levels are similar to what I have measured in Minnesota over the past 24 years.
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