(Reuters) - Remember 2010? U.S. and international scientists reckon it tied for the warmest year on record, supporting findings of unequivocal global climate change. Climate skeptics remain unconvinced.
Those who study the climate skeptic position say this raises echoes of scientific controversies of the past, including the debate over the health hazards of tobacco.
In Washington, the most vocal denier of human-caused climate change is U.S. Senator James Inhofe, an Oklahoma Republican who has repeatedly dismissed the idea as a hoax.
"Actually, right now we're in the third year of a cooling period," Inhofe said in December, before the January release of statistics from the U.S. National Climate Data Center, NASA and the World Meteorological Organization showing 2010 tied for the hottest year since modern record-keeping began in 1880.
WMO showed it tied with 2005 and 1998.
NCDC and NASA had a tie with 2005.
The latest temperature data have not changed Inhofe's stance, said Matt Dempsey, Inhofe's spokesman.
"Why would one year, even if it was the hottest year on record, influence the senator's view?" Dempsey said in a phone interview. "There's a lot of factors that go into this. To have one hot year and use that to suggest that there's catastrophic man-made global warming sounds a little hollow."
Brenda Ekwurzel, a climate expert at the Union of Concerned Scientists, which maintains that human activity is a primary cause of global warming, agreed that one year is less significant than the record over decades, which she said conclusively showed a warming world.
DECADES OF WARMING
"Any one year can vie with another year or be extremely hot and break all records," Ekwurzel said by telephone. "It's more important to look at the decadal average."
Looking at it on that time scale, she said, showed that 2001-2010 was the hottest decade since 1880. The previous decade, 1991-2000, was next-warmest, and 1981-1990 was the third-warmest. "This trend is undeniable," Ekwurzel said.
It's been a rough year or so for scientists and others who say that data shows human activities, especially the burning of fossil fuels, accelerate the climate-warming greenhouse effect. Climate skeptics are quick to point this out. To wit:
-- Skeptics allege scientists manipulated climate research, citing the so-called "climategate" scandal of December 2009, in which leaked e-mails from scientists at the University of East Anglia's Climatic Research Unit in Britain appeared to show scientists sniping at climate deniers and trying to block publication of articles critical of their findings.
At least four reviews of the case have exonerated the climate scientists but skeptics maintain it cast doubt on all climate research that showed a consistent warming trend.