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September 2007

The Impact of Climate Change on Florida’s Everglades, Alaska’s Wrangell-St. Elias

What do Florida's Everglades and Alaska's Wrangell-St. Elias have in common? Both face uncertain futures as temperatures rise.

I’ve chosen Hells Bay for my three-day canoe trip not just for the challenge (“It’s hell to get into and hell to get out,” the old-timers say), but because it’s one of the few navigable waterways in the park that remain off-limits to motors. The Everglades’ premier backcountry route, the Wilderness Waterway, has devolved into a loud, smoky highway, overrun by powerboaters who can make the trip in five hours.

But in Hells Bay, I hear only the wind through the mangrove canopy, which is anchored by a twisted web of red roots rising out of the mud. The stream is just a few inches deep and no more than a couple of feet wider than the thwarts of my canoe. It loops and turns back and forth on itself, a twisting, bewildered mass of water that offers few hints about the direction of its flow. As I push deeper into the mangrove swamp, the sense of isolation intensifies.

This is like no canoeing I’ve ever done. Every acceleration is followed within seconds by abrupt braking, to make a hairpin turn. I average one mile an hour, paddling into the hottest, quietest part of the day. An alligator slides into the water on my approach; a red-shouldered hawk circles overhead.

Mangrove trees are salt-tolerant, which means that as thesea level has risen–it has come up nine inches since 1930–the trees have begun marching toward the interior, supplanting the freshwater flora of the Everglades’ famous “river of grass.” The river of grass is one of several distinct ecosystems, all of which connect in a delicate interplay–an interplay that’s been disrupted by the one-two punch of sea level coming up, and a lack of fresh water coming down.

“In terms of the responses to climate change, what’s happening here is totally off the charts,” says David Hallac, the park’s chief biologist. “The Everglades are on the verge of becoming a monoculture.”

So far, the mangroves are the big winners. But even they may not be able to keep up, according to University of Miami geologist Harold Wanless. “The coast is literally falling apart in response to the sea level rise,” he says. “Hurricanes take 20 or 30 meters of coastline each time. The higher storm surges kill the trees and wash away peat underneath, and you end up with these large, dead, open-water areas.”

The stream gets wider as I wend near the coast, then opens into a series of ponds and bays. Eagles soar above, and a small, black-tipped shark cruises below. Toward evening, a cold front slides in, bringing a 15-knot crosswind. My canoe handling like an unwieldy kite, I muscle across the rough water, stopping to rest in the lee of pods of mangroves, one of which is inhabited by millions of dragonflies.

Finally, I arrive at Hells Bay Chickee, the raised platform that will be my night’s campsite. Trying not to think about the sign warning against eating five species of mercury-contaminated fish, I set up my hammock, cook dinner, and lie back, amazed that I have this whole place to myself.

It had been a hectic few days. I had started my visit to the area in the outer Keys, snorkeling around the outer barrier reef with Chris Bergh, director of the Nature Conservancy’s Florida Keys Program. The reef is a line of defense that protects extreme southern Florida from the full onslaught of storms. It also provides structure for fish populations that are just starting to recover from decades of overfishing. But in some sections, only 10 percent of the coral survives; the rest has succumbed to rising temperatures and bleaching brought on by ocean acidification–an effect of higher CO2 levels.

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