Last Year: The warmest year on record (again)
Every January for the past decade, you've heard the same basic news story: It announces that last year was one of the warmest years on the planet since 1880, when record-keeping began in earnest.
Well, it's January, and yes, last year was one of the warmest years on record since 1880. In fact, 2010 ties the record with 2005 as the hottest year in the historical record.
This year it was Deke Arndt's turn to break the news in the National Oceanic and Atmospheric Administration's annual teleconference.
"This continues a trend that has gone on for several decades," Arndt said. "This is the 34th consecutive year with temperatures above the 20th century average."
In fact, you need to go back to 1976 to find a year with below-average global temperatures, as measured on thermometers around the world.
Record Precipitation, Too
But what about rain and snow?
"Preciptiation is highly variable from place to place, so there were lots of dry areas, lots of wet areas. But when we average those out, it was also the wettest year on record," Arndt said.
Warm air can hold more water, but Arndt can't say whether there's a direct link between the record-tying heat and the record-breaking precipitation, like the devastating floods in Pakistan.
These are global averages, but Arndt said the story was different for those of us in the United States.
"Both the temperature and precipitation were above normal," he said. "It was the 23rd warmest year on record in the United States. It was the 36th wettest year on record -- these both fall into the upper third of the United States climate history, which dates back to 1895."
Of course, there's a lot of variation across the globe, so it's not at all surprising to see records in some places but not in others. Last year's global record was due in part to an unusually hot Pacific Ocean, caused by the El Nino weather pattern.
A Global Trend
John Christy, a professor of atmospheric science at the University of Alabama in Huntsville, sees the same general warming trend in his measurements of global temperature. Those are based on satellite measurements of the planet's air from the surface up to 35,000 feet.
"The take-home lesson is that if you have an El Nino, you're going to have a hot year," he says. "But I just finished shoveling eight inches of global warming off my driveway this Monday here in Alabama. So whatever the globe is doing, your local weather can have a completely different picture, that's for sure."
And as for the long-term global trend? David Easterling of the National Climatic Data Center in Asheville, N.C., says that's our doing. Global warming is driven by our growing emissions of carbon dioxide and other greenhouse gases.
"Although we can't attribute any individual event, such as the Russia heat wave, it's always important to keep in mind that the probability of these kinds of events do increase as the climate warms," he says.
And, yes, that's the same conclusion you heard from the world's most respected climate scientists in 2010, 2009 and 2008. The story on global warming isn't changing. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.