Stats not so hot after all
Taking the Earth's temperature is not an exact science -- results likely to vary
By LORRIE GOLDSTEIN
Since the debate over man-made global warming is "over" and a "consensus" has been achieved, how hot was last year anyway?
Here's what three of the world's leading agencies monitoring climate change say.
NASA's Goddard Institute for Space Studies, headed by James Hansen who is an advisor to Al Gore, says 2007 was the second warmest year on record.
Meanwhile, the U.S. National Oceanic and Atmospheric Administration says it was the fifth warmest.
And Britain's Meteorological Office (the MET), which does its analysis in conjunction with the University of East Anglia, and which at the start of the year predicted 2007 would likely be the warmest on record, says it was the seventh warmest.
NASA says 2005 is the warmest year on record and 2007 tied for second with 1998.
The MET says 1998 is the warmest year on record and 2007, in terms of warming trends, isn't statistically different from any year going back to 2001.
In August, NASA grudgingly rejigged its ranking for the hottest years in the U.S. after Canadian blogger Steve McIntyre (
www.climateaudit.org), pointed out a calculating error. That resulted in 1934 nudging out 1998 as the hottest year on record in the U.S., although NASA says the change is statistically insignificant.
What it all means is that taking the Earth's temperature is not an exact science. It's also a relatively new science, going back no more than 150 years on a 4.5 billion-year-old planet.
Best then to take each new prediction or claim that one year or another was the hottest, or hotter, or less hot, with a grain of salt.
As Hansen himself writes: "Ranking relative to other years is likely to vary among results of different groups that make global temperature analyses, because of differences in data sources, methods of combining data sets, and areas included in the averaging."
The MET notes where, how and when observations are made influence the data, as well as what instruments are used -- everything from satellites to ground stations --and how averages are calculated.
NASA, the NOAA and the MET agree the Earth has been steadily warming in recent decades, that the most recent decade contains the hottest years on record, that it is very likely man-made global warming is driving climate change and that the Earth is responding to these changes. But even here, a caution.
As NOAA spokesman Scott Smullen recently told the Washington Post: "Most of the observed increase in global average temperatures in the last 50 years is very likely due to increased human-induced greenhouse gas concentrations, but we cannot yet discern warming trends in the last 10 years with the same resolution."
Award-winning BBC science journalist David Whitehouse, a doctorate in astrophysics and author of The Sun: A Biography, goes further.
Writing in the New Statesman last month in an article entitled "Has Global Warming Stopped?" he asserts:
"The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming -- the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly."
This is a minority view in the scientific community, which argues such phenomena as ocean and aerosol cooling explain recent minor temperature variations.
Even so, it's wise to heed Whitehouse's closing warning:
"I have heard it said, by scientists, journalists and politicians, that the time for argument is over and that further scientific debate only causes delay in action. But the wish to know exactly what is going on is independent of politics and scientists must never bend their desire for knowledge to any political cause, however noble. The science is fascinating, the ramifications profound, but we are fools if we think we have a sufficient understanding of ... the Earth's atmosphere's interaction with sunlight ... We know far less than many think we do or would like you to think we do."
but anywho....
