Greenhouse skeptics point out that the lower atmosphere up to 7 kilometers has not warmed
over the last 20 years, since satellites started making measurements.
Using a computer model of the tropical ocean, they artificially warmed
the climate and found that winds and ocean currents work to cool the eastern Pacific.
Graham's study delves even deeper to explain how the tropical ocean warmed
Of particular interest, they report that surface temperatures for the western Arctic Ocean actually showed a significant cooling in winter and autumn, while the lower atmosphere warmed
by a significant amount in winter in both the central and western Arctic.
Christy of the University of Alabama at Huntsville, an atmospheric scientist who analyzed the satellite data quoted in the report, says he certainly agrees with the conclusion that Earth has no warmed
as quickly as models predicted.
A study of temperature records in the United States, China and the former Soviet Union indicates that these regions have warmed
over the last 40 years, but that most of the warming has occurred at night, with daytime temperatures staying about the same through the decades.
Evidence suggests that slight variations in Earth's orbit triggered the shifts and that greenhouse gases provided some of the force that cooled and warmed
the planet; during the ice ages, carbon dioxide levels dropped by more than 30 percent.