The 'consensus' catechism about global warming

George Will summarises for Newsweek outlines "the 'consensus' catechism" for warmists, all but one point of which are unproven:

1. Global warming is happening.
2. It is our (humanity's, but especially America's) fault.
3. It will continue unless we mend our ways.
4. If it continues we are in grave danger.
5. We know how to slow or even reverse the warming.
6. The benefits from doing that will far exceed the costs.

Only the first tenet is clearly true, and only in the sense that the Earth warmed about 0.7 degrees Celsius in the 20th century. We do not know the extent to which human activity caused this [ie., so called Anthropogenic Global Warming]. The activity is economic growth, the wealth-creation that makes possible improved well-being—better nutrition, medicine, education, etc. How much reduction of such social goods are we willing to accept by slowing economic activity in order to (try to) regulate the planet's climate?

We do not know how much we must change our economic activity to produce a particular reduction of warming. And we do not know whether warming is necessarily dangerous. Over the millennia, the planet has warmed and cooled for reasons that are unclear but clearly were unrelated to SUVs. Was life better when ice a mile thick covered Chicago? Was it worse when Greenland was so warm that Vikings farmed there? Are we sure the climate at this particular moment is exactly right, and that it must be preserved, no matter the cost?

Are we? Read on here. Bear in mind, as you do, the concluding paragraph from the Independent Summary for Policymakers [pdf] of the IPCC's draft Fourth Assessment Report:

There is no evidence provided by the IPCC in its Fourth Assessment Report that the
uncertainty [surrounding the hypothesis for Anthropogenic Global Warming] can be formally resolved from first principles, statistical hypothesis testing or modeling exercises. Consequently, there will remain an unavoidable element of uncertainty as to the extent that humans are contributing to future climate change, and indeed whether or not such change is a good or bad thing.

The fact is that the warmists in the consensus crowd have a problem: they're scaring themselves (and us) to death over something that's highly uncertain -- as the Wall Street Journal notes, the latest IPCC report contains "startling revisions of previous U.N. predictions" -- and still not proven. The science As Canadian climatologist Dr. Tim Ball says:

This in fact is the greatest deception in the history of science. We are wasting time, energy and trillions of dollars while creating unnecessary fear and consternation over an issue with no scientific justification.

And what are those "startling revisions of previous U.N. predictions," and what has the UN/IPCC conceded it got wrong? Again, the Wall Street Journal summarises:

Take rising sea levels. In its 2001 report, the U.N.'s best high-end estimate of the rise in sea levels by 2100 was three feet. [The 2007] report's high-end best estimate is 17 inches, or half the previous prediction. Similarly, the new report shows that the 2001 assessment had overestimated the human influence on climate change since the Industrial Revolution by at least one-third.

Such reversals (and there are more) are remarkable, given that the IPCC's previous reports, in 1990, 1995 and 2001, have been steadily more urgent in their scientific claims and political tone.

U.N. scientists have relied heavily on computer models to predict future climate change, and these crystal balls are notoriously inaccurate. According to the models, for instance, global temperatures were supposed to have risen in recent years. Yet according to the U.S. National Climate Data Center, the world in 2006 was only 0.03 degrees Celsius warmer than it was in 2001--in the range of measurement error and thus not statistically significant.

The models also predicted that sea levels would rise much faster than they actually have. The models didn't predict the significant cooling the oceans have undergone since 2003--which is the opposite of what you'd expect with global warming. Cooler oceans have also put a damper on claims that global warming is the cause of more frequent or intense hurricanes. The models also failed to predict falling concentrations of methane in the atmosphere, another surprise.

Meanwhile, new scientific evidence keeps challenging previous assumptions. The latest report, for instance, takes greater note of the role of pollutant particles, which are thought to reflect sunlight back to space, supplying a cooling effect. More scientists are also studying the effect of solar activity on climate, and some believe it alone is responsible for recent warming.

All this appears to be resulting in a more cautious scientific approach, which is largely good news. [The 2007] report is also missing any reference to the infamous "hockey stick," a study by Michael Mann that purported to show 900 years of minor fluctuations in temperature, followed by a dramatic spike over the past century. The IPCC featured the graph in 2001, but it has since been widely rebutted.

The WSJ's conclusion:

The IPCC report should be understood as one more contribution to the warming debate, not some definitive last word that justifies radical policy change. It can be hard to keep one's head when everyone else is predicting the Apocalypse, but that's all the more reason to keep cool and focus on the actual science.

LINKS: Inconvenient Kyoto Truths - George Will, Newsweek
Global warming: The cold hard facts - Dr Tim Ball, Canada Free Press
Climate of opinion: The lates UN report shows the "warming" debate is far from settled - Wall Street Journal
Independent Summary for Policymakers - Fraser Institute [62-page PDF]

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