NOW TO THE crux of the Al Gore argument — the idea that rising carbon dioxide levels are causing an increase in 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.
Gieg has lots more slides to show. He points out that within his lifetime, there was a three-decade period of unusually low temperatures that culminated in the popular consciousness with the awful winter of 1976-77. Back then, scientists started sounding the alarm about a new ice age.
Of course, it’s long been thought that the world would end either in fire or in ice. These days, the scientists are shouting fire. And in all his years around environmental issues, Giegengack has never heard so much shouting. “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.”
Giegengack says things started to get this way around 1988. There was a horrifically hot summer season that year, and drought led to seemingly apocalyptic fires in Yellowstone National Park. Something in those fires was galvanizing. Al Gore, who made his first run for president in 1988, published his first environmental jeremiad, Earth in the Balance, a few years later. Around the same time, the newly formed Intergovernmental Panel on Climate Change was making noise, and governments met first in Rio de Janeiro and then in Japan to forge agreements on “targets” for carbon emission cutbacks. The resulting Kyoto Protocol has been ratified by most of the countries on Earth — none of which are doing very well at actually meeting the target cutbacks — but very notably not by the United States.