How About That Precautionary Principle Now?

Some years ago environmentalists set up the Precautionary Principle as a dodge to stop economic development. You shouldn’t do anything, they insist, unless you are pretty certain that it is safe.

Now they argue that, since everyone agrees that global warming will melt the glaciers on Greenland and inundate the low lying areas of the world that we should cut back on greenhouse gas production in coal and hydrocarbon burning. It is the precautionary thing to do.

But what about the new research that links cosmic ray intensity with cloud cover? According to Steven Milloy two Danish researchers, Henrik Svensmark and Eigil Friis-Christensen, have established an experimental link between the intensity of cosmic rays reaching the earth and low-level cloud cover.

Their hypothesis was based on a strong correlation between levels of cosmic radiation and cloud cover -- that is, the greater the cosmic radiation, the greater the cloud cover. Clouds cool the Earth's climate by reflecting about 20 percent of incoming solar radiation back into space.



The hypothesis was potentially significant because during the 20th century, the influx of cosmic rays was reduced by a doubling of the Sun's magnetic field, which shields the Earth from cosmic rays.

A hypothesis is fine, but does it check out? Thank you, Mr Vice-President, I’m glad you asked, because I know you will be anxious to update your documentary An Inconvenient Truth with the latest science.

Svensmark published a paper last week in the Proceedings of the Royal Society in which he claimed that his team “had experimentally verified the physical mechanism by which cosmic rays affect cloud cover.”

Here is the press release announcing the experimental results. It shows that cosmic rays do indeed form minute aerosols of sulphuric acid as hypothesized.

But at RealClimate they are having none of it. They list five “missing steps” between establishing that cosmic rays create “ultra-small aerosol particles” and that cloud cover is controlled by the combination of cosmic rays and variations in the sun’s magnetic field.

The chaps at Junk Science are quite excited. They aren’t as vested in the “enhanced greenhouse hypothesis” as the chaps at RealClimate.

So the controversy continues.

Of course, whatever the science says the question is: what should we do about climate change? What is the precautionary thing to do?

Should we try to reverse anthropic changes like the increase in greenhouse gages over the last century? Or should we adapt to any changes in climate and sea level as they occur?

And anyway, how do anthropogenic changes play out against natural fluctuations such as earth orbit oscillations, solar radiation fluctuations, and anything else going on that we haven’t even noticed yet?

Mr President, are we safe?