Global warming? Look at the numbers

Lorne Gunter, National Post
Published: Monday, August 13, 2007

In his enviro-propaganda flick, An Inconvenient Truth, Al Gore claims nine of the 10 hottest years on record have occurred in the last decade. That's been a common refrain for environmentalists, too, and one of the centrepieces of global warming hysteria: It's been really hot lately -- abnormally hot -- so we all need to be afraid, very afraid. The trouble is, it's no longer true.

Last week, NASA's Goddard Institute for Space Studies -- whose temperature records are a key component of the global-warming claim (and whose director, James Hansen, is a sort of godfather of global-warming alarmism) -- quietly corrected an error in its data set that had made recent temperatures seem warmer than they really were.

A little less than a decade ago, the U.S. government changed the way it recorded temperatures. No one thought to correlate the new temperatures with the old ones, though -- no one until Canadian researcher Steve McIntyre, that is.

McIntyre has become the bane of many warmers' religious-like belief in climate catastrophe. In 2003, along with economist Ross McKitrick, McIntyre demolished the Mann "hockey stick" --a graph that showed stable temperatures for 1,000 years, then shooting up dangerously in the last half of the 20th Century.

The graph was used prominently by the UN and nearly every major eco lobby. But McIntyre and McKitrick demonstrated it was based on incomplete and inaccurate data.

To NASA's credit, when McIntyre pointed out their temperature errors they quickly made corrections.

Still, the pro-warmers who dominate the Goddard Institute almost certainly recognized the impacts these changes would have on the global-warming debate, because they made no formal announcement of their recalculations.

In many cases, the changes are statistically minor, but their potential impact on the rhetoric surrounding global warming is huge.

The hottest year since 1880 becomes 1934 instead of 1998, which is now just second; 1921 is third.

Four of the 10 hottest years were in the 1930s, only three in the past decade. Claiming that man-made carbon dioxide has caused the natural disasters of recent years makes as much sense as claiming fossil-fuel burning caused the Great Depression.

The 15 hottest years since 1880 are spread over seven decades. Eight occurred before atmospheric carbon dioxide began its recent rise; seven occurred afterwards.

In other words, there is no discernible trend, no obvious warming of late.

Ever since the correction became a hot topic on blogs, the pro-warmers have tried to downplay its significance, insisting, for example, that the alterations merely amount to "very minor rearrangements in the various rankings."

It's true the changes aren't dramatic. But the optics are.

Imagine if the shoe were on the other foot. Imagine the shrieking of the warmers if we had previously thought that hot years were scattered throughout the past 130 years, but after a correction the warmest years could be seen to be concentrated in the past decade.

They would insist the revised data proved their case. They would blitz every news organization and talk show. They would demand to be allowed to indoctrinate school children on the evils of cars and factories.

So they shouldn't be permitted to brush aside this new data, which makes their claims harder to prove.

Ten years ago, warmers found a similarly small error in the temperature data collected by weather satellites. The satellites were a thorn in their sides because while the warmers were insisting the Earth was getting hotter, the satellites showed it was in fact cooling ever so slightly.

Then the warmers discovered that the scientists who maintained the orbiting thermometers had failed to account for orbital decay, the almost infinitesimally small downward drift of the "birds" every year.

When the effects of drift were added into the observations, the cooling was found to be just 0.01 degree per decade rather than the 0.04 degrees previously claimed.

On this basis, the warmers now insisted then that even the satellites were somehow in agreement with their theory.

Of course, the current NASA changes are only for data collected in the United States. But available surface temperature readings cover only half the planet even today. Before the Second World War, they covered less than a quarter. So U.S. readings for a period that goes as far back as 1880 are among the most reliable there are.

Perhaps we will have uncontrollable warming in the future, but it likely hasn't started yet.