It is a big week for the environmental movement. Friday the Intergovernmental Panel on Climate Change will issue its newest assessment on global climate change – the latest in four reports stretching back to 1990. Friday’s is the first such report since the Kyoto Protocol came into force and, of course, the first in some time that will see a warm reception in both houses of the U.S. Congress.

If nothing else, it will be a reminder to the many European countries who are falling behind on their Kyoto pledges to reduce carbon emissions. It will also remind climate change advocates in the United States of their failure to instill any sense of urgency into Americans on global warming.

Yet, whatever tomorrow’s report brings in the way of promises and sound bites, it is certain to show how little authority Americans give to the apocalyptic gloom of climate change diviners. Americans have only yawned at the fearmongering of global warming activists, and environmentalists know it.

Here’s a good example of why. When the National Oceanic and Atmospheric Administration forecasted an above-average year of hurricanes in May 2006, CNN, ABC News, The Washington Post – just about every mainstream news media – fingered global warming as the culprit for the rash of severe tropical storms. There was talk of adding a “category six” to the Saffir-Simpson Scale, and The New York Times published an editorial that used Katrina as justification for a “Global Warming Preparedness Act.”

But then the 2006 season turned out to be a dud. The government forecasted 13 to 16 named storms, seven to nine of those becoming hurricanes. In fact, it was a subpar season by historical standards: There were nine named storms and only five of those dubbed hurricanes.

Now, this is important for two reasons. For one, it proves that even today’s most sophisticated weather models are horribly inaccurate – even for a forecast a mere six months out. Prior to the 2005 hurricane season, the NOAA predicted 11 named storms, six becoming hurricanes.

As it turned out, 28 were named and 15 became hurricanes. If the meteorological community cannot get in the ballpark on annual estimates, how much confidence should Americans give to 50-, 100- or 500-year forecasts?

The answer is very little. Tomorrow’s IPCC report is expected to halve previous forecasts for sea-level rise as a result of better data. Predictions for air temperatures are sure to be widely different this time around as well. Well-meaning climatologists would be wise to wonder when constant revisions to an obvious guessing game become irrelevant.

And this gets at the second and more important point: credibility. This column was nearly titled, “How to discredit a good cause,” because the greatest proponents for tackling climate change are in fact doing the most to disgrace it. Every time a climatologist claims an abnormal weather pattern must – absolutely must – be a consequence of climate change, he or she is acting as an activist, not a scientist. Ultimately, he or she is usually shown to be wrong – as environmentalists have been proven on everything from global cooling to global famine and so on.

Certain Capitol Hill politicians and climate change buffs are also making a big mistake in handling their opposition. In October of last year, Sens. Jay Rockefeller and Olympia Snowe wrote a threatening letter to Exxon Mobil CEO Rex Tillerson.

The note essentially told Exxon brass to stop supporting climate change dissenters who have “manufactured controversy,” or else. Many climatologists – including the well-known MIT professor Richard Lindzen – have claimed that they have been demonized and ostracized for nonconforming to popular views.

It is one thing for scientists and congressmen to be frustrated by the dissent of a vocal minority. It is very much another for them to issue veiled threats to squash technical and policy debates. If the green crowd were as confident in their models as they claim they are, they should not need to bully the few skeptics who remain. Such obvious suppression of opinion is not a redeeming detail to people on the fence of the debate – that is, most Americans.

As a start, it would help the climate change cause if do-gooder media-types and climatologists admitted the frailty of their predictions and stuck with the basics: The Earth is warming, likely because of both natural climate variation and human-created emissions. Getting Al Gore and other “think tanks” to stop politicizing the debate would draw more people to the cause as well.

What climate change advocates need to remember is this: Most people understand the seriousness of severe global warming. Finger-pointing and dire scenarios of human plight 100 years out are pointless. If the American green movement is to be relevant, it must first show that it favors technical debate and is interested more in the science than the politics. If it does that, American voters themselves will drive the policy change that is needed.

Darren Bernard welcomes comments at [email protected].