Just när många av oss trodde att Michael Mann och hans hockeyklubba var ett minne blott, dyker tingesten upp igen. Enligt BBC News har Mann återigen analyserat temperaturdata för de senaste 2000 åren och kommit fram till att temperaturerna på norra halvklotet är definitivt osedvanligt höga historiskt sett. Dessutom skriver BBC News följande:
A new study by climate scientists behind the controversial 1998 “hockey stick” graph suggests their earlier analysis was broadly correct.
BBC förringar sedan kritiken mot Manns hockeyklubba.
The graph – indicating that Northern Hemisphere temperatures had been roughly constant for 1,000 years (the “shaft” of the stick) before turning abruptly upwards in the industrial age – featured prominently in the Intergovernmental Panel on Climate Change’s (IPCC) 2001 assessment.
But some academics questioned its methodology and conclusions, and increasingly strident condemnations reverberated around the blogosphere.
One US politician demanded to see financial and research records from the scientists involved.
However, a 2006 report from the National Research Council (NRC), commissioned by the US Congress, broadly endorsed its conclusion that Northern Hemisphere temperatures in the late 20th Century were probably warmer than at any time in the previous 400 years, and perhaps at any time during the previous 1,000 years.
Kontentan är alltså enligt BBC att det aldrig var något större fel med hockeyklubban och att den nu är tillbaka “same but improved”.
Critics of the idea of man-made climate change argue that conditions 1,000 years ago were as warm as, if not warmer than, they are today.
The new paper adds to the evidence against that notion. One of the analytical methods used suggests that temperatures in the Mediaeval Warm Period could have been no higher than they were in about 1980; the other suggests they were no higher than those seen 100 years ago.
Ten years on from the study that provoked all the ire, Michael Mann’s conclusion is that far from being broken, “the hockey stick is alive and well”.
Sensationella nyheter, inte sant?