WCR Defines the Climate Debate

There’s little doubt now in Washington that the science issues this Report has scrutinized during the last two years are what’s driving the greenhouse debate. Anyone who needs any convincing should have attended the global warming fest run by the Union of Concerned Scientists (UCS) in Washington, D.C., Sept. 30.

It’s no secret that the UCS meeting was a dress rehearsal for the White House global warming show Oct. 6. Most of the same actors star in both shows. The props are the same. And of course, the scripts are almost identical.

Through the years, we’ve maintained a steady fire on three major flaws in the gloom-and-doom forecasts of massive global warming:

1. The only truly global measure of lower atmospheric temperature—the satellite record—shows no warming at all since the data started in 1979.

2. Climate models are unable to account for the fact that surface temperatures did not warm as predicted.

3. Adding carbon dioxide to the air makes the planet greener, not browner.

Every scientific presentation made at the UCS meeting attempted to deny these realities. Although the results were interesting, they weren’t too successful. Virtually in response to the information this Report disseminates, UCS speakers brazenly cautioned that the satellite data are wrong, that climate models can now explain why the planet cooled between 1940 and 1975 when it should have warmed, and that plants do not respond to carbon dioxide increases much after an initial growth spurt.

“THE SATELLITES ARE NO GOOD”

So spoke Kevin Trenberth of the National Center for Atmospheric Research. Trenberth published a much-cited paper in Nature claiming that a climate model had shown the satellite temperatures can’t be right about the lack of warming in the tropics, and that therefore the satellite data themselves must be wrong.

The keepers of the satellite, John Christy and Roy Spencer, have demonstrated that their records and actual weather balloon measures of global temperature are remarkably similar, a correlation Report readers know by heart. Trenberth is now arguing that some weather balloon records have biases introduced when their instrument package changes (as happened in Australia).

That the satellite and the balloons would make the same mistakes when averaged over the globe—month after month and year after year—sure seems to strain the limits of credibility. But that’s the song the UCS was singing, and that’s what we can expect to hear from the White House for the rest of the year.

LUKEWARM EXPLANATIONS

For years now, one of the gloomsters’ great weaknesses has been the global cooling that occurred between 1940 and 1975, a period most people thought should have continued the warming trend established in the early part of the century.

Climate modeler Jerry Mahlman told UCS that his new (not yet published) model does pick up the midcentury cooling, and then resumes warming in the 1980s, continuing to do so for the next 500 years. Judging from his presentation, the actual warming will be so obvious and so large in the next two decades that there won’t be any need for debate.

All right, then. Mahlman has quantitatively set the bar, and we shall see. As the response to his presentation noted, if the surface, weather balloon, and satellite records look like his model says they will for the next two decades, then the issue will be much clearer.

That’s when, in a moment of high drama, a voice from the back of the room—Trenberth—pronounced: “The satellites are no good.”

We’ll bet Mahlman’s model shows that the lower atmosphere—say, between 5,000 and 30,000 feet, has warmed smartly in the last decade. But in fact, it hasn’t. Or perhaps his computer can predict a big warmup of the surface yet none in this layer, breaking at least two of the known laws of physics. We’ll also bet that the satellite won’t warm nearly as much—if at all—as the computer tells it to.

BROWNER, NOT GREENER

That’s not a cut on the EPA Administrator. But it is what the UCS audience was told about the effect of carbon dioxide on plants. Walter Oechel of San Diego State University argued that, based on his studies of Arctic plants, the much-vaunted “fertilization” effect that results from increased carbon dioxide is not liable to take place on a global scale.

Oechel’s field studies in the Arctic show that CO₂ initially stimulates growth, but that its salutary effect peters out after a few years. Thus the ultimate effect might not be “global.”

But, averaged across the same globe, there has been nothing more global in this entire script than the observation that plants are drawing an increasing amount of CO₂ out of the air each year as the concentration increases. Every year, when the world’s forests (primarily in the Northern Hemisphere) leaf out, CO₂ comes out of the atmosphere. When the leaves decompose, it goes back up. This annual swing means more leafy green matter. As Figure 1 shows, it is indisputable that things are getting greener on a global scale.

Figure 1.  Each year, plants pull CO₂ out of the atmosphere.  This chart is a measure of how much.  The increasing trend is evidence of a greener planet.

SONGS IN THE KEY OF DENIAL

If the UCS meeting, as we suspect, is pretty much the same old song and dance as the White House is going to put on, its signature piece is a medley of denial of the realities that are this Report’s refrain. The chorus is simple: The satellite shows no warming, the models can’t figure this out, and the planet’s getting greener.

Reference:

Trenberth, K., and J.W. Hurrell (1997). Spurious trends in satellite MSU temperatures from merging different satellite records. Nature, 396, 164–167.

Reprise: Wanna Bet?

Jerry Mahlman’s forecast of a continuous warming trend between the 1970s and 2470 is not the first prediction that will be verified or vilified within the working lifetime of the principal actors in the global warming drama. On February 3, 1995, Richard Kerr wrote in Science:

“For climate change to live up to predictions, the minimal warming of the 1980s will have to accelerate into the next millennium. Climate modeler James Hansen of the Goddard Institute for Space Studies in New York City expects it will; even the short satellite record will begin to fall in line with model predictions by the end of the century, he says.”

We’re now halfway between when that prediction was made and January 1, 2000. The weather balloon temperature trend for the last decade is flat. The surface thermometers show no net warming in the last 10 years, and the satellite didn’t warm a lick.