If you were thinking Al Gore then I guess you would be half-right. Like many, I internalized the idea of climate crisis from seeing Al Gore’s An Inconvenient Truth. Keep in mind that I was no fan of Al Gore and I voted against him the last time he ran yet I found the ideas and arguments he presented in his documentary so compelling that I came to be utterly convinced of the reality of man-made global warming.
I was wrong and so is Al Gore.
The man who changed my mind is University of Pennsylvainia geologist Bob Giegenback, affectionately referred to by his students as “Gieg.” In an interview with Philadelphia Magazine, Giegenback – a political supporter of Al Gore – takes Gore’s vision of global warming to task:
He has described Al Gore’s documentary as “a political statement timed to present him as a presidential candidate in 2008.” And he added, “The glossy production is replete with inaccuracies and misrepresentations, and appeals to public fear as shamelessly as any other political statement that hopes to unite the public behind a particular ideology.” This from a guy who voted for Gore in 2000 and says he’d probably vote for him again.
Ouch. If Gore’s contention that rising carbon dioxide is causing rising global temperatures is wrong then what is actually going on? Giegenback explains:
The professor hits a button on his computer, and the really long-term view appears — the past 650,000 years. In that time, the Earth’s temperature has gone through regular cycles of rise and fall. The best explanation of those cycles was conceived by a Serbian amateur scientist named Milutin Milankovi´c. Very basically, Milankovi´c said this: The Earth’s orbit around the sun is more or less circular, but when other planets align in certain ways and their gravitational forces tug at the Earth, the orbit stretches into a more elliptical shape. Combined with the tilt of the Earth on its axis as it spins, that greater or lesser distance from the sun, plus the consequent difference in solar radiation that reaches our planet, is responsible for long-term climate change.
But what about Gore’s graphs where he mapped carbon dioxide levels to global temperature?
To determine temperatures and carbon dioxide levels in the distant past, scientists rely on what they call the “proxy record.” There weren’t thermometers. So researchers drill deep down into the Antarctic ice sheet and the ocean floor and pull up core samples, whose varying chemical elements let them gauge both the CO2 levels and the temperatures of the distant past.
Gieg clicks a button, and three charts come together. The peaks and valleys of the Milankovi´c cycles for planetary temperature align well with the ocean-floor estimates, and those match closely the records of carbon dioxide concentrations and temperature indications from ice cores. So, the professor maintains, these core samples from the polar ice and ocean floor help show that the Earth’s temperature and the levels of carbon dioxide in the atmosphere have been in lockstep for tens of thousands of years.
Of course, that was long before anybody was burning fossil fuels. So Giegengack tells his students they might want to consider that “natural” climatic temperature cycles control carbon dioxide levels, not the other way around. That’s the crux of his argument with Gore’s view of global warming — he says carbon dioxide doesn’t control global temperature, and certainly not in a direct, linear way.
Well what about the rising sea levels and the millions of climatic refugees Gore warned us about?
“Sea level is rising,” Giegengack agrees, switching off the sound. But, he explains, it’s been rising ever since warming set in 18,000 years ago. The rate of rise has been pretty slow — only about 400 feet so far. And recently — meaning in the thousands of years — the rate has slowed even more. The Earth’s global ocean level is only going up 1.8 millimeters per year. That’s less than the thickness of one nickel. For the catastrophe of flooded cities and millions of refugees that Gore envisions, sea levels would have to rise about 20 feet.
“At the present rate of sea-level rise,” Gieg says, “it’s going to take 3,500 years to get up there. So if for some reason this warming process that melts ice is cutting loose and accelerating, sea level doesn’t know it. And sea level, we think, is the best indicator of global warming.”
Gieg has something to say about science and politics too.
“I don’t think we’re going to have a rational discussion of this question in the present environment,” he says. “The scientists are mad because they think nobody in Washington is listening to them. So it’s all either apocalyptic disaster or conflict of interest. If you suggest that we’re not going to hell in a handbasket because the rate of global warming is low compared to so many other environmental issues that we’re enduring, then you’re accused of being in the employ of the oil companies and you’re labeled a Republican.”
It’s hard to disagree with Geig on that last point. In just the past few weeks we’ve seen a call from a Weather Channel meteorologist in her blog that meteorologists who deny man-made climate change be decertified by the American Meteorological Association. We’ve seen governors move to unseat state climatologists who are skeptical of global warming and the blogosphere is saturated with accusations that any scientist who is skeptical of global warming is in the pocket of the Republican Party and Big Oil. Even Nuremburg style trials for climate change skeptics are not off the table and why shouldn’t they be? The prevalent labeling of climate change skeptics as “deniers” draws an obvious and purposeful parallel to holocaust revisionists and the last I checked they were throwing those guys in jail. I find these calls for the supression of scientific dissent extremely disturbing. If scientists such as Giegenback are wrong then let the science evince their errors. Equating a scientific opinion about climate with holocaust denial is absurd and the quickness with which people are willing to join the witch hunt lemming-like and add their shouts of “burn them at the stake” is an unsettling testament to our herd mentality.