Satellite data shows Earth's climate is changing unevenly - The Weather Guys - USATODAY.com

"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.