Changes

==The Hockey Stick Reconstruction==

==The Hockey Stick Reconstruction==

[[Image:Hockey stick chart ipcc.jpg|right|thumb|300px|The Hockey stick graph as shown in the 2001 IPCC report.]]

[[Image:Hockey stick chart ipcc.jpg|right|thumb|300px|The Hockey stick graph as shown in the 2001 IPCC report.]]

One of the main arguments for anthropogenic global warming during the 3rd IPCC report was a temperature reconstruction done by climatologist Michael Mann.  The resulting graph of the earth's mean temperature is shaped like a hockey stick, and it is used as evidence for the unusualness of the earth's temperature in the past few decades.  However, Stephen McIntyre and economist Ross McKitrick later discovered serious flaw in the statistical methods used to construct the hockey stick graph.  Because of this, the 4th Assessment Report of the IPCC included several different temperature reconstruction methods instead of favoring just one hypothesis.

One of the main arguments for anthropogenic global warming during the 3rd IPCC report was a temperature reconstruction done by climatologist Michael Mann.  The resulting graph of the [[global mean temperature]] is shaped like a hockey stick, and it is used as evidence for the unusualness of the earth's temperature in the past few decades.  However, Stephen McIntyre and economist Ross McKitrick later discovered serious flaw in the statistical methods used to construct the hockey stick graph.  Because of this, the 4th Assessment Report of the IPCC included several different temperature reconstruction methods instead of favoring just one hypothesis.

==Natural variability of the climate system==

==Natural variability of the climate system==