Day By Day

Friday, May 11, 2007

More Problems with Global Warming

Olaf Stampf, writing in Der Spiegel, explains the problem with computer simulations:

A healthy dose of skepticism is a good idea, especially when scientists become all too confident and make themselves out to be oracles. But there can be a wide gap between their predictions and the end result -- a fundamental weakness of all computer simulations that present only incomplete pictures of reality.

In the early years, for example, computer modelers underestimated the influence of aerosols, especially the sulfur particles that are released into the atmosphere during the combustion of oil and coal or during volcanic eruptions. These pollution particles block sunlight and thus cause significant cooling. The failure to adequately take aerosols into account explains why earlier models predicted a more drastic rise in temperatures than those in use today. One major unknown in the predictions depends on how quickly countries like China will filter out the pollutants from their power plant emissions -- if the air becomes cleaner it will also heat up more rapidly.

Other factors that can either weaken or strengthen the greenhouse effect are still not fully understood today. For example, will the carbon dioxide trapped in the world's oceans be released as the water heats up, thereby accelerating global warming? And how much faster do land plants and sea algae grow in a milder climate? Plant proliferation could bind more carbon dioxide -- and serve to slow down the greenhouse effect.

But the main problem lies in correctly calculating the effects of clouds. The tops of clouds act as mirrors in the sky, reflecting sunlight back into space -- thus cooling the planet. But the bottom sides keep the heat radiated by the earth from escaping into the atmosphere -- causing temperatures to rise.

Which of the two effects predominates depends primarily on the altitude at which clouds form. Simply put, low clouds tend to promote cooling while high clouds increase warming. So far scientists agree on only one thing, namely that more clouds will form in a greenhouse climate. They just don't know at which altitude.

Even the most powerful computer models are still too imprecise to simulate the details. However, the clouds alone will determine whether temperatures will increase by one degree more or less than the average predicted by the models. This is a significant element of uncertainty. "Clouds are still our biggest headache," concedes Erich Roeckner of the Max Planck Institute for Meteorology.

This is only a portion of his indictment of the climate change hysterics. Read the whole thing here. Then go here and read another skeptical argument from climate scientist, Hans Von Storch.

My favorite quote from Von Storch:
"Unfortunately many scientists see themselves too much as priests whose job it is to preach moralistic sermons to people."

And that's a big part of the problem.