2001: The Eastern U.S. Keeps Its Cool While The World Warms

ScienceDaily (Jan. 31, 2001) — Much of the Earth has warmed over the last half-century, but the eastern half of the United States has shown a cooling trend. NASA-funded research indicates cooler temperatures in the eastern U.S. are caused by an increase in sun-shielding clouds produced by warmer ocean temperatures in the Pacific.

Eastern U.S. temperatures have displayed a cooling trend of 0.1° Celsius per decade, while global temperatures warmed by that same amount from 1950 to 1997. The researchers used a computer climate model to see if this regional cooling could be caused by changes in sea surface temperature. Robinson said that in the GISS model, "Warmer sea surface temperatures in the tropical Pacific cause greater cloud cover over the eastern United States. This increased cloud cover is directly responsible for the cooling." The brightness of a cloud causes a large percentage of incoming solar radiation to be reflected back into space, thus keeping the atmosphere cooler than if the cloud wasn’t there.

2001: Higher Ocean Temperatures Linked To Cooling In Midwest

ScienceDaily (Jan. 22, 2001) — CHAMPAIGN, Ill. — While Earth as a whole has warmed during the last half-century, much of the continental United States has grown slightly colder. The trend toward cooler temperatures in the central and eastern United States is due to warmer ocean temperatures, a University of Illinois researcher says.

Solar Activity Between 1250-1850 Linked To Temperature Changes In Siberia

The scientists discovered a strong link between regional temperatures and the solar activity in the period 1250-1850, concluding that the sun was an important driver of preindustrial temperature changes in the Altai.

The observation that the reconstructed temperatures followed the solar forcing with a delay of 10 to 30 years is particularly interesting. The strong rise in temperature in the Altai between 1850 and 2000 can not be explained by solar activity changes, but rather by the increased concentration of the greenhouse gas CO2 in the atmosphere.