NASA gives global warming theory a boost
It's one of the most controversial subjects on earth, but if data from NASA is to be believed, the past decade on the planet has been the warmest ever.
Well, when NASA says ever, that's since records began in 1880 - it has been very very hot at other periods in the earth's history. The earth was molten once, scientists think.
The survey, conducted by the Goddard Institute for Space Studies (GISS) that 2009 was the warmest year since records began. 2008 was the coolest year of the decade.
James Hansen, who has come under attack from those who dispute global warmings exist, said: "There's substantial year-to-year variabilty of global temperature cause by the tropical El Niño-La Niña cycle. But when we average temperature over five or ten years to minimize that variability, we find that global warming is continuing unabated."
The last three decades, according to GISS data, show that the surface temperature is heating up by 0.36F per decade. GISS says that this means there's a clear warming trend, although things didn't show the same trend between the 1940s and the 1970s.
This will cause anger among opponents of the theory of global warming. GISS says climate scientists agree that higher levels of carbon dioxide and other greenhouse gases are the prime factors for causing global warming. The other key factors are changes in the Sun's irradiance, oscillations of sea surface temperatures in the tropics and changes in aerosol levels. GISS believes that these effects do not account for the level of heating that's going on.
Hansen said: "There's a contradiction between the results shown here and popular perceptions about climate trends. In the last decade, global warming has not stopped."