Prometheus 6

The dispute:

Many climatologists, along with policymakers in a number of countries, believe the rapid temperature rise over the past 50 years is heavily driven by the burning of fossil fuels and other human activities that have spewed carbon dioxide and other "greenhouse gases" into the atmosphere. A vocal minority of scientists say the warming climate is the result of a natural cycle.

The evidence for climate change:

Global temperatures this year are about 1.36 degrees Fahrenheit (0.75 Celsius) above the average between 1950 and 1980, according to the Goddard analysis. Worldwide temperatures in 1998 were 1.28 degrees Fahrenheit (0.71 Celsius) above that 30-year average. The data show that Earth is warming more in the Northern Hemisphere, where the average 2005 temperature was two-tenths of a degree above the 1998 level.

Climate experts say such seemingly small shifts are significant because they involve average readings based on measurements taken at thousands of sites. To put it in perspective, the planet's temperature rose by just 1 to 1.5 degrees Fahrenheit over the past century.

The evidence this 50 year increase (which is a longer time frame than any climate cycle I'm aware of) is a cyclic change:

one skeptic, state climatologist George Taylor of Oregon, said it is difficult to determine an accurate global average temperature, especially since there are not enough stations recording ocean temperatures.

"I just don't trust it," Taylor said of the new calculation, noting that Goddard's findings are "mighty preliminary."

World Temperatures Keep Rising With a Hot 2005
By Juliet Eilperin
Washington Post Staff Writer
Thursday, October 13, 2005; A01

New international climate data show that 2005 is on track to be the hottest year on record, continuing a 25-year trend of rising global temperatures.

Climatologists at NASA's Goddard Institute for Space Studies calculated the record-breaking global average temperature, which now surpasses 1998's record by a tenth of a degree Fahrenheit, from readings taken at 7,200 weather stations scattered around the world.

The new analysis comes as government and independent scientists are reporting other dramatic signs of global warming, such as the record shrinkage of the Arctic sea ice cover and unprecedented high ocean temperatures in the Gulf of Mexico.

Late last month, a team of University of Colorado and NASA scientists announced that the Arctic sea ice cap shrank this summer to 200 million square miles, 500,000 square miles less than its average area between 1979 and 2000. And a scientist at the National Oceanic and Atmospheric Administration determined that sea surface temperatures in the Gulf of Mexico were higher in August than at any time since 1890, which may have contributed to the intense hurricanes that struck the region this year.