GISS Benchmarking The Baseline « Musings from the Chiefio

This is the period from 1931 to 1940 measured against ‘all data’. It, as you can see, has a very warm Arctic. So at the end of the day I’m left to conclude that a significant part of our present “Hot Arctic” is a result of comparing it to an abnormally cold period in the baseline interval.

Can White Roofs Battle Global Warming? - Green Inc. Blog - NYTimes.com

Other studies have found that while roofs do reduce air-conditioning costs by 20 percent in hot, sunny weather, this may be countered by the additional energy required to heat buildings during the winter months in cold climates.

Mr. Bonan said that while the study’s main findings supported the idea that painting roofs would effectively reduce global temperatures, “we also need to consider the costs of heating of buildings because of that.”

White roofs may be best suited for cities with a year-round warm climate, he said.

[Aren't a lot of American roofs currently covered with white snow?]: Snow covers 70 pct of the U.S. « Fire Earth

The United States has recorded its most extensive snow cover of the winter. Moderate to heavy snow and ice has covered up to 70% of the country in the past few days extending the snow coverage from 47.5% on January 27th to the largest snow cover of the winter at 69.7% on January 31st, the National Operational Hydrologic Remote Sensing Center (NOHRSC) reported.