In July 1995, a five-day heat wave killed 739 people in Chicago. The daily high temperatures don't seem all that oppressive --ranging from 89 to 106 degrees—but disaster came because nighttime lows didn't drop below the low-70s in a city where many people lived in substandard conditions without air conditioning, and were loath to open their doors fearing crime.

Philadelphia, experts say, could face a similar tragedy as predictions see the city's climate matching Atlanta's within decades.

Infrequent, but intense, spikes in temperature would be of particular concern. While that will mean fewer cold-related deaths, projections from the United Kingdom Meteorological Office have some 361 Philadelphians dying annually by 2020, with 682 average deaths by 2050.

The Goddard Institute for Space Studies goes even further, predicting the potential for some 938 annual heat-related deaths should Philadelphians not acclimate to climate change. (Philadelphia, already ranked as one of the nation's top five cities for mortality in hot conditions, has some 146 heat-related deaths a year.)

If current projections hold, University of Delaware climatology expert Laurence Kalkstein says heat-related deaths would be a "major killer, rivaling the present number of deaths from leukemia." (He notes that birth rates and sperm counts could also be adversely affected.)

When Vanity Fair published its "Green Issue" in April, the centerpiece was computer renderings of what New York City and Washington D.C. would look like by 2100 should global warming go unchecked. Manhattan was a collection of skyscrapers poking out of the water, while one would have to swim from the Lincoln Memorial to make it over to the Washington Monument. Frightening images, indeed. But, they're probably no more shocking than what would happen to Atlantic City and the rest of the Jersey shore. Specifically, much of it would disappear from the face of the earth. Last November, Princeton University climate expert Michael Oppenheimer was among three experts who released a report focused on how rising sea levels would effect the New Jersey coast. "Atlantic City," he said during a subsequent interview, "will eventually be lost to the sea."

Oceans do rise, but it seems mankind is speeding up the process, which is a particular problem in a region that, with a $16 billion tourism industry, has seen substantial population growth and property investment in recent decades.

In the past 20,000 years, since the last glacial maximum, the global sea level has risen about 400 feet. In the next 90 years, it's expected to grow at least 2 feet. May not sound like much until you consider that each foot of sea-level growth translates into some 100 yards of land lost. As in two football fields could conceivably disappear from the Jersey shore, which could be disastrous in developed spots like Atlantic City, or for people who've shelled out $5 million for an Avalon beachfront.

If projections of a 1.22-meter rise hold, some 3 percent of the state—including barrier islands and environmentally essential wetlands, will be lost to the Atlantic Ocean for good.

Now for the bad news? It's probably too late to stop the sea from rising, although the overall global level can yet be mitigated with quick action to cut back on emissions.

On Monday, Citizens for Pennsylvania's Future (PennFuture) released the results of a poll that found a majority of Philadelphians don't feel as if their elected leaders are doing enough to protect the environment. "An astonishing 85 percent of voters," said pollster Terry Madonna, "reported they are more likely to vote for a candidate for mayor who made improving the city's environment and its sewer, water and transportation infrastructures a top priority." Fifty-six percent of voters said the environment should be among the top issues in the upcoming mayoral race.

If the region's average temperature rises just 1.8 degrees Fahrenheit, Pennsylvania will lose 9 percent of perching birds species that now call it home. (They'd fly north in order to find the climate they once had here.) That's not just a problem for birders, but could have a negative impact on seed dispersal, plant pollination and pest control, according to Ann Fisher, a recently retired climate specialist at Penn State University. In other words, they wouldn't eat some pests (both to humans and crops) or help with plant growth as they currently do.

And that's not even mentioning what would happen to various species, both native and migratory, many of which are endangered, should rising sea levels inundate wetlands along the Jersey shore and the Delaware Bay. This is of particular concern for the some 1.5 million migrating birds that hit the Jersey shore each year, and the 24 native endangered species.

"Say you have robins out on your lawn now," says Fisher. In a few years, "you might have an overall different mix of birds outside your house. It's unlikely that it'll be dramatically different, it'll happen gradually, but one day, you may say it's been 10 years since you've seen one. Don't expect there to be 25 different species, though. You may have 20 of the same ones, and five new ones instead."

Forget, for a moment, that runoff could make any fish caught in a local river too poisoned to eat. But with rising temperatures, both on land and water, cold-water fisheries could collapse. Of course, we could shift to warm-water fishing. Bottom line for recreational fishermen: The days of brook trout may be ending while bass could be on the rise.

Tropical diseases are already migrating north into cooler climates. Just last month, in a story about how global warming and its related floods and droughts are already fueling the spread of epidemics to unprepared locales, the Washington Post quoted Harvard Medical School's Paul Epstein as saying, "Things we projected to occur in 2080 are happening in 2006." While cholera and dengue fever aren't Delaware Valley concerns, West Nile virus and Lyme disease are. Dr. Dina Fonseca, assistant curator of molecular ecology at the Academy of Natural Sciences, says an eight-degree rise in average temperature may not seem like much, but that it could bring an increase in mosquito-borne disease to the region. Estimates on the rise in average temperature range from four to 10 degrees. "We've had 19 of the 20 warmest years on record since 1980," says Jon Nese, co-author of The Philadelphia Area Weather Book. "You don't need me to interpret what means."

"It will extend their breeding season," says Fonseca, who works closely with mosquitoes that carry West Nile. "Instead of [mid-May], it'll start in April, even March, giving them more opportunity to infect people.."

The new climate could also invite new breeds of mosquitoes and the diseases they carry.

Penn State researchers found that "malaria-carrying mosquitoes would find more suitable habitat in a region that becomes warmer and wetter." Also, more Lyme-carrying deer ticks would thrive.

As ocean levels rise, salt water will be pushed farther up the Delaware River. According to Oppenheimer's global-warming study, should sea level rise more than .73 meters, unsafe salinity levels would reach 110 miles up the Delaware to the city's Torresdale water-supply intake. And were that to happen, Philadelphia's water supply would risk contamination. "At some point, it could become unhealthy and undrinkable," says Oppenheimer.

Such a change in water supply would also affect fish, and wildlife that feed on plants that get nutrients from the river.

While increased precipitation would make more water available than ever, quality would be harmed by increased runoff, both from flooding and from rapid snow melt. And not only would that make the water untenable, it would be more costly to purify. "The potential for a wetter regional climate, punctuated by droughts, suggests higher water supply management costs to protect both surface and ground-water sources and to provide more storage capacity," the Penn State study maintained.

While we're not smog-covered Los Angeles, unless the city institutes some hardcore pollution-emissions standards, air quality will continually become a bigger problem for residents. (This is a global greenhouse-gas problem that will manifest itself here.) That translates into more respiratory and allergy problems. "Ozone action days," says Nese, "we'll have a lot more of them."

If the warm water that fueled Hurricane Katrina's deadly path toward the Gulf Coast is the harbinger that many experts say it is, it's not absurd to think the Mid-Atlantic will see monster storms in the future. When warm ocean water travels farther north it brings an increased chance of tropical storms with it. (Accompanied by stronger storm surges, experts predict 100-year storms could arrive four times a century.) And if that were to happen, Philadelphia could suffer more intense consequences since the last one took a path up Delaware Bay in the Colonial era.

"The newspaper accounts at the time said the waters of the river 'whipped into a fury that would have drowned out Niagara [Falls] itself,'" says Nese. "We'd have widespread structural damage and substantial flooding in Center City."

Nese says the worst case for Philly would be a storm that's centered just south of the bay; in such a scenario the counterclockwise winds would push ocean water straight up the river. "The number of hurricanes may not change," says Oppenheimer, "but the intensity is shifting."

This March, the local Clean Air Council issued a press release entitled, "Global Warming Is Disrupting Traditional Signs of Spring." In it, Penn State biology professor Eric Post said, "These are the first warning signs that bigger changes lie ahead." The group's research found that:

• Lilacs and honeysuckle are blooming six days early,
• Northern cardinals are singing 22 days early;
• Frogs are starting their mating season 12 days early;
• Canadian geese, robins and whip-poor-wills are arriving earlier;
• Columbine, forest phlox, butterfly weed and shooting star are all blooming earlier, and
• Lakes and rivers are thawing six days earlier.

"The future impact that global warming could have on plants and animals in our region," says Paul Meyers of the University of Pennsylvania's Morris Arboretum, "is certainly something to be concerned about."

In other words, we're already seeing the signs of global warming and we need to be braced for more to come.

It will be harder for local farmers to keep their land (thanks to sprawl, regulations on what fertilizers they can use and the arrival of new pests and weeds). With a need to import more foodstuffs to the region—along with increased expenses for local farmers—the price of some foods could increase. (From a seafood perspective, mussels are the perfect example, as 71 percent of the species in the region could disappear.) It would be much easier to grow tobacco farther north than it's currently grown and, on the upside, soybeans, corn and tree fruit growers in the region would benefit. However, livestock producers could see a "significant decline" in production.

"There will be an intensification of precipitation events. Look at New England," Oppenheimer says, referring to the massive rain and flooding that caused evacuations there earlier this month. "We'll have big flooding rainstorms and ultra-heavy snowstorms. They're already becoming more frequent and I expect that to increase. There will be a decrease in moderate storms, but when it rains, it will pour."

The EPA concurs with Oppenheimer, stating that we'll see more floods and droughts as a result of climate change. A projected 50 percent increase in fall rain would replenish the state's water supply, but lead to soil erosion. Penn State researchers project that within the next decade, the region could be seeing an additional 3 inches of precipitation on average each year; by 2095, that increase is projected to triple.

Highlighting the uncertainty belying this issue, Nese says he isn't certain we'll see substantially more rain. He even predicts that with warmer temperatures, "there will be less snow in the Poconos, hampering the Delaware Valley's winter fun."