Climate change skeptics are saying that the Earth has been cooling since 1998 and that this disproves that climate change is caused by human activity. A piece on the BBC website What happened to global warming? (9th October 2009) gives one example of the claim.
RealClimate.org has a piece to counter this view A warming pause? (6th October 2009).
Summarising the RealClimate piece:
- The claim about a warming pause uses cherry-picked data starting with the year 1998, which was a hot year at the end of a strong El Nino warm phase.
- The claim uses the Hadley Centre data set which excludes the fastest warming part of the planet – the Arctic.
- The GISS data from NASA does not show the “cooling” effect.
The RealClimate piece should not be taken as a criticism of the Hadley Centre – they deliberately miss out the Arctic region because there are no ground measuring stations there. The GISS data fills this gap by other readings.
But even using cherry-picked data the “no warming” claim will soon be invalid as the Earth has returned to an El Nino warm phase and even on Hadley data the “pause” will disappear.