The Hockey Stick vs The Ice Cores
The diagram below is the famous so called “Hockey Stick” graph (named because of its shape) contained in the 2001 Intergovernmental Panel on Climate Change (IPCC). This single diagram did more to get the man made global warming bandwagon going that anything else and it is featured heavily in Al Gores film “An Inconvenient Truth”, a film that was instrumental in popularising alarm about man made global warming.
The article “The rise and fall of the Hockey Stick” explores the impact this single graph had and how it was shown to be based on poor methodology which had produced a false result.
The Hockey Stick graph claims to show “unprecedented” and strong global warming in the 20th century after centuries of much more gentler climate oscillations.
In the past two decades the National Oceanic and Atmosphere Administration (NOAA) has undertaken a long program of work which has reconstructed past temperatures based on ice core samples taken from the Greenland and Antarctica ice sheets. This very significant research programme can construct a very accurate temperature record for Greenland and Antarctica going going back hundreds of thousands of years.
The animation below shows this temperature reconstruction based on NOAA data stepping back int time. The animation places the current Hockey Stick graph in a progressively larger climate history.
You can judge for yourself if the warming in the 20th century is ‘unprecedented’