From the USA Today Weather Blog
This has been in my inbox for a couple of weeks, so on a fairly quiet day for weather, I thought I’d put this out there. John Christy of the University of Alabama-Huntsville reported earlier this month that the Earth’s climate change over the past 30 years has been rather uneven: It’s gotten much warmer in the Arctic and, at the same time, cooler in the Antarctic.
Christy and his colleague Roy Spencer, who are known in some quarters as global warming skeptics, use data from satellites to measure the temperature of the Earth. The more well-known NASA GISS and National Climatic Data Center data sets primarily measure surface temperatures.
Overall, Christy found that Earth’s atmosphere warmed an average of about about 0.72 degree F in the past 30 years, according to NOAA and NASA satellites. More than 80 percent of the globe warmed by some amount. However, while parts of the Arctic have warmed by as much as 4.6 degrees F in 30 years, Christy says that much of the Antarctic has cooled, with parts of the continent cooling as much as the Arctic has warmed (see map, above; click to enlarge).
“If you look at the 30-year graph of month-to-month temperature anomalies, the most obvious feature is the series of warmer-than-normal months that followed the major El Nino Pacific Ocean warming event of 1997-1998,” says Christy. “Right now we are coming out of one La Nina Pacific Ocean cooling event and we might be heading into another. It should be interesting over the next several years to see whether the post La Nina climate ‘re-sets’ to the cooler seasonal norms we saw before 1997 or the warmer levels seen since then,” he says.
He adds that most of the warming found in the satellite data has taken place since the beginning of the 1997-98 El Nino, and that Earth’s average temperature showed no detectable warming from December 1978 until the 1997 El Nino.
Meanwhile, the Washington Post reported yesterday that the USA “faces the possibility of much more rapid climate change by the end of the century than previous studies have suggested, according to a report led by the U.S. Geological Survey.”