Remember when scientists who had cast doubt on global temperature studies boldly embarked on an effort to "reconsider" the evidence?
They have. And they conclude that their doubt was misplaced.
UC Berkeley physicist Richard Muller and others were looking at the so-called urban heat island effect – the notion that because more urban temperature stations are included in global temperature data sets than are rural ones, the global average temperature was being skewed upward because these sites tend to retain more heat. Hence, global warming trends are exaggerated.
In fact, Muller's analysis of the data trend supports the key conclusion of prior groups that urban warming does not unduly bias estimates of recent global temperature change."
A paper, made available Thursday, amounts to the second time that Muller et al have had to back away from a key plank of climate skeptics' argument that Earth is simply on a natural temperature path and man-made greenhouse gases are not warming the atmosphere.