Moreover, he notes that warmer winters actually pose certain health risks. “As the winters become warmer, the conditions that prevent a lot of the infectious diseases are lost,” Mann explains. “For instance, many scientists have implicated the 1998 outbreak of West Nile Virus in New York with the unusually warm winter that year, which provided a much longer season for the breeding of the mosquitoes that carry it.”

But the main question voters may have in mind when stepping into the booths for 2008 is how much of global warming is actually human induced. In Mann’s view, we’re responsible for a good bit of it. “Skeptics say that climate warming is due to natural consequences, but we know that some of the changes that we’re seeing are unprecedented in a very long-term scale,” he says. “For example, mountain glaciers that have been around for thousands of years are disappearing before our eyes.”

The human implication, as Mann explains it, enters the equation through models that analyze the Earth’s climate system. When including only natural global warming factors such as variations in the Sun’s output, Mann says the models don’t even come close to the actual climate conditions of this century and last.

“The only way we can match the overall warming during the twentieth century is by including the human impact—increased greenhouse gas concentrations, pollution, and the changing patterns of land use,” Mann says.

Cautious solutions
And while Lomborg doesn’t dispute the existence of global warming, he warns that we should act cautiously in searching for solutions. “People want to cut carbon now, because it feels good,” he says. “But the problem is it costs a lot, and will do very little good. Th at’s basically the flaw in the Kyoto Protocol.”

According to Lomborg, if the U.S. and other countries had gone along with the Kyoto Protocol, it would have delayed global warming by seven days and at a cost of $180 billion a year.

“For half that amount, the UN estimates that we could solve all of the world’s basic problems right now,” he says. “We could make clean drinking water, sanitation, basic health care, and education available to every human being on the planet.”

But Mann counters that there are more cost-effective ways of addressing the problem at its source, including looking to renewable energy sources, encouraging greener practices at the consumer and industrial levels through legislative mandates and incentives, and employing cleaner ways of using existing fossil fuel sources.