Credit: Andrew popik

The recent tsunami and last year’s active hurricane season have many people speculating on the impact of global warming. Doomsday scenarios resembling The Day After Tomorrow are popping up on the Internet. Reports from the International Climate Change Task Force and the climateprediction.net experiment are adding fuel to the fire.

A lot of the doomsday speculation is about thermohaline circulation and the Gulf Stream shutting down. Thermohaline circulation is a pattern that distributes heat and water across the globe, and the Gulf Stream is part of the system. Much of the plot of The Day After Tomorrow was centered on the global circulation pattern.

Scott Sheridan, assistant professor of geography, said he showed the film to his climate change class.

“Our class was rooting for the wolves by the end,” Sheridan said. “The movie made the assumption that if you shut this off you’re going to go from heating up the planet to freezing it whereas more realistically, if you have a warming planet and the Gulf Stream slows down it just means parts of Europe won’t warm up as fast,” Sheridan said.

The film exaggerated conceivable climate changes.

“The thermohaline circulation does have variability, and it is plausible that it could slow down, which could cause changes in the climate system, but even at its most rapid, you’re talking about subtle changes over several decades,” Sheridan said. “You’re not talking about somehow turning it into an ice ball in a week and a half.”

“That movie sucks,” said Doug Sheldon, senior justice studies major. “The fact that the ice age just came.”

Sheldon doesn’t believe global warming is responsible for any of the recent natural disasters like the tsunami or the hurricanes that struck the southern United States last fall.

“They’re natural occurrences that just happen,” he said.

Many think the same thing as Sheldon, but as much as doomsday scenarios exaggerate the possible outcomes of global warming, any increase in the earth’s surface temperature can change the climate.

“A lot of people outside of climatology tend to underestimate how a really small change in temperature can have a huge impact,” Sheridan said. “If you look at the last ice age when we were just about under the end of the glaciers here, we were talking about a planet that was only 5 degrees (Celsius) colder.”

Ice and oceans and polar bears, oh my!

The International Climate Change Task Force, co-chaired by Sen. Olympia Snowe of Maine, suggested that global warming is approaching a critical point of no return in the report, “Meeting the Climate Challenge.” The report proposes an objective to prevent the global surface temperature from increasing by more than 35.6 degrees Fahrenheit above the Earth’s temperature before the industrial revolution era.

If the earth’s surface temperature passes the 35.6 degrees Fahrenheit threshold, the report predicts a risk of an abrupt climate change.

The ice sheets in West Antarctica and Greenland could melt causing the sea level to rise about 33 feet, and the Gulf Stream, which warms the European subcontinent, could shut down.

Ice sheets are a major part of ecosystems. If they melt, many species of animals, like polar bears, would suffer.

“Polar bears need the ice sheets to last a certain amount of time. If the ice sheets don’t last around as long, they have less time to eat and therefore give birth to weaker pups and the cycle continues,” Scott Sheridan, assistant professor of geography, said.

Computer experiment gives range of results

The climateprediction.net experiment is suggesting an even bleaker scenario. The first results show that greenhouse gases could cause the global surface temperature to increase by almost 52 degrees Fahrenheit.

“If you think the last ice age was only 5 degrees (Celsius) cooler, you’re talking about more than twice the difference,” Sheridan said.

“Basically what one group did was run different climate scenarios on different computers at the same time around the world,” Sheridan said. “Eleven degrees (Celsius) was the high end, but a lot of people have pretty much talked about how those high numbers are absolutely unrealistic.”

The experiment is an attempt to forecast the twenty-first century climate. Participants in the experiment download software that allows them to run a version of the climate model of the Met Office in England, a world leader of weather-related services. The model runs while the computer is hibernating and reports the results to institutions around the world.

Contact enterprise reporter Liz Buckley at [email protected]