Friday, June 29, 2007

Lots of Evidence for Global Warming Skepticism

The National Post in Canada has made a crusade of giving a voice to all the global warming skeptics -- most of whom have excellent scientific credentials -- that the mainstream media has ignored.

Here is a compilation of their articles on the subject. Warning: to see these articles you will have to register for a free trial. Unlike most such free trials, they will not ask for your credit card number, and will not bill you credit card if you forget to cancel.
And the latest entry, “Read the sunspots.”
The fact that science is many years away from properly understanding global climate doesn’t seem to bother our leaders at all. Inviting testimony only from those who don’t question political orthodoxy on the issue, parliamentarians are charging ahead with the impossible and expensive goal of “stopping global climate change.” Liberal MP Ralph Goodale’s June 11 House of Commons assertion that Parliament should have “a real good discussion about the potential for carbon capture and sequestration in dealing with carbon dioxide, which has tremendous potential for improving the climate, not only here in Canada but around the world,” would be humorous were he, and even the current government, not deadly serious about devoting vast resources to this hopeless crusade.

Climate stability has never been a feature of planet Earth. The only constant about climate is change; it changes continually and, at times, quite rapidly. Many times in the past, temperatures were far higher than today, and occasionally, temperatures were colder. As recently as 6,000 years ago, it was about 3C warmer than now. Ten thousand years ago, while the world was coming out of the thou-sand-year-long “Younger Dryas” cold episode, temperatures rose as much as 6C in a decade -- 100 times faster than the past century’s 0.6C warming that has so upset environmentalists.

[. . .]

Our finding of a direct correlation between variations in the brightness of the sun and earthly climate indicators (called “proxies”) is not unique. Hundreds of other studies, using proxies from tree rings in Russia’s Kola Peninsula to water levels of the Nile, show exactly the same thing: The sun appears to drive climate change.

However, there was a problem. Despite this clear and repeated correlation, the measured variations in incoming solar energy were, on their own, not sufficient to cause the climate changes we have observed in our proxies. In addition, even though the sun is brighter now than at any time in the past 8,000 years, the increase in direct solar input is not calculated to be sufficient to cause the past century’s modest warming on its own. There had to be an amplifier of some sort for the sun to be a primary driver of climate change.

Indeed, that is precisely what has been discovered. In a series of groundbreaking scientific papers starting in 2002, Veizer, Shaviv, Carslaw, and most recently Svensmark et al., have collectively demonstrated that as the output of the sun varies, and with it, our star’s protective solar wind, varying amounts of galactic cosmic rays from deep space are able to enter our solar system and penetrate the Earth’s atmosphere. These cosmic rays enhance cloud formation which, overall, has a cooling effect on the planet. When the sun’s energy output is greater, not only does the Earth warm slightly due to direct solar heating, but the stronger solar wind generated during these “high sun” periods blocks many of the cosmic rays from entering our atmosphere. Cloud cover decreases and the Earth warms still more.

The opposite occurs when the sun is less bright. More cosmic rays are able to get through to Earth’s atmosphere, more clouds form, and the planet cools more than would otherwise be the case due to direct solar effects alone. This is precisely what happened from the middle of the 17th century into the early 18th century, when the solar energy input to our atmosphere, as indicated by the number of sunspots, was at a minimum and the planet was stuck in the Little Ice Age. These new findings suggest that changes in the output of the sun caused the most recent climate change. By comparison, CO2 variations show little correlation with our planet’s climate on long, medium and even short time scales.

In some fields the science is indeed “settled.” For example, plate tectonics, once highly controversial, is now so well-established that we rarely see papers on the subject at all. But the science of global climate change is still in its infancy, with many thousands of papers published every year. In a 2003 poll conducted by German environmental researchers Dennis Bray and Hans von Storch, two-thirds of more than 530 climate scientists from 27 countries surveyed did not believe that “the current state of scientific knowledge is developed well enough to allow for a reasonable assessment of the effects of greenhouse gases.” About half of those polled stated that the science of climate change was not sufficiently settled to pass the issue over to policymakers at all.
We don’t claim to have the scientific knowledge to judge the “global warming due to human activity thesis.”

But we do know enough about science to know that groupthink, careerism and political ideology have often distorted scientific findings. Indeed, these things have often created a consensus that has later proven to be nonsense.

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