Global warming students see two problems emerging that will have sizable economic impact. First, because the water is warmer (which fuels hurricanes), there is the potential for the storms to cause more damage. And second, if sea levels are already higher (due to warmer water, plus the effects of melting ice sheets), a storm surge could be even worse.

If there is a rise of five to six feet in the sea level "over the next century or two, one-third of Florida is gone," says Miller.

Field agrees: "With every meter (39.37 inches) of sea level, you lose a substantial amount of South Florida."

In an area like New York City, which sits close to the ocean, if you combine rising levels and a nor'easter, "you'll have things like the subway filling with water," Field says.

Another problem with warming is the heat. By the end of the century, we could see heat waves in Los Angeles or San Francisco go from 12 days to 100 days, says Field. That heat also magnifies smog problems, meaning there are "more kids with asthma, more people who can't go outside," he says. "There will be a greater number of people who have air pollution-related health conditions." What's more, warming helps some types of ragweed, as well as bug-borne diseases like malaria and dengue fever, he says. So America could expect to see "more serious impacts from hay fever," as well as more malaria and dengue fever cases.

Short supplies?
Drought, climate changes and storm damage could also lead to shortages or disruptions in food, water and energy supplies.

"We've already seen impacts of warming on the yields of corn, wheat and barley," says Field. "Worldwide, for every degree the temperature goes up, the yield goes down 8 percent."

An aging water and sewer infrastructure, melting snow packs in the western mountains and increasing heat and drought in the West have several experts predicting struggles over the water supply -- and an end to cheap water.

By 2020 -- just about the time today's toddlers are in high school -- "I think it's untenable for water to be free or as cheap as it is in many places," says Romm.

There would likely be "increased water prices and shortages in some areas," says Miller, "first affecting agriculture in the West. It would have a profound effect on the economy in the West."

If everyone in America recycled their junk mail, $370 million in landfill dumping fees could be saved each year.

But Mother Nature is also throwing some curve balls.
"In a lot of cases, the effects from climate changes interact in unexpected ways," says Field. For example, as water levels in San Francisco Bay rise, salty sea water is flowing upriver, which is a big problem because that water is used to irrigate fertile California farmland.

 "After a big storm, you already have salt levels that are unacceptable," he says. "The concern is that instead of getting it once every five years, you get it once every month, and eventually the water will be too salty to use."

-- Posted: Oct. 4, 2007