Important: For the record

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"Global cooling" is nonsense. Now someone is sure to pipe up and say "Maybe figures don't lie, but liars sure do figure" -- but of course that would first tar the folks who came up with the phony "global cooling" numbers, but that little bit of reality doesn't matter to the committed denialist.

AP IMPACT: Statisticians reject global cooling

WASHINGTON – Have you heard that the world is now cooling instead of warming? You may have seen some news reports on the Internet or heard about it from a provocative new book. Only one problem: It's not true, according to an analysis of the numbers done by several independent statisticians for The Associated Press. . . .

In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time.

"If you look at the data and sort of cherry-pick a micro-trend within a bigger trend, that technique is particularly suspect," said John Grego, a professor of statistics at the University of South Carolina.

Yet the idea that things are cooling has been repeated in opinion columns, a BBC news story posted on the Drudge Report and in a new book by the authors of the best-seller "Freakonomics." Last week, a poll by the Pew Research Center found that only 57 percent of Americans now believe there is strong scientific evidence for global warming, down from 77 percent in 2006.

Global warming skeptics base their claims on an unusually hot year in 1998. Since then, they say, temperatures have dropped — thus, a cooling trend. But it's not that simple.

Since 1998, temperatures have dipped, soared, fallen again and are now rising once more. Records kept by the British meteorological office and satellite data used by climate skeptics still show 1998 as the hottest year. However, data from the National Oceanic and Atmospheric Administration and NASA show 2005 has topped 1998. Published peer-reviewed scientific research generally cites temperatures measured by ground sensors, which are from NOAA, NASA and the British, more than the satellite data.

The recent Internet chatter about cooling led NOAA's climate data center to re-examine its temperature data. It found no cooling trend.

"The last 10 years are the warmest 10-year period of the modern record," said NOAA climate monitoring chief Deke Arndt. "Even if you analyze the trend during that 10 years, the trend is actually positive, which means warming."

The AP sent expert statisticians NOAA's year-to-year ground temperature changes over 130 years and the 30 years of satellite-measured temperatures preferred by skeptics and gathered by scientists at the University of Alabama in Huntsville.

Statisticians who analyzed the data found a distinct decades-long upward trend in the numbers, but could not find a significant drop in the past 10 years in either data set. The ups and downs during the last decade repeat random variability in data as far back as 1880. . . .

UPDATE: Mother Jones blogger Kevin Drum's review of the story:

Here's a thought experiment for you. Suppose you had some data and you wanted to know what to make of it. The problem is that the subject of the data happens to be a political hot potato, and you know that everyone you show it to is going to cherry-pick just the pieces that bolster all their favorite preconceived notions.
Well, here's an idea: Show the data to a bunch of different experts but remove all the labels first so they have no idea what they're looking at. Just give them the raw numbers and ask what they think.

That's the delightful idea that AP science writer Seth Borenstein hit on a few days ago. He sent data on global warming to several independent statisticians but didn't tell them what the numbers represented. He just wanted to know if they thought the data showed any kind of flattening or decrease in recent years.

Answer: No. "Statisticians who analyzed the data found a distinct decades-long upward trend in the numbers, but could not find a significant drop in the past 10 years in either data set. The ups and downs during the last decade repeat random variability in data as far back as 1880." In other words, contrary to the chatter from global warming skeptics, the Earth didn't start cooling a decade ago. It only looks that way if you compare current temperatures to 1998, which was an unusually hot year due to a strong El Niño. But if you look at all the data, instead of just cherry-picking one single comparison, the news, unfortunately, remains grim. The current decade is the hottest on record, and the next one will be hotter still.