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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.

Climatologists say that natural cycles do exert an influence on temperature, but that the current warming trend is driven primarily by a human-produced buildup of greenhouse gases in the atmosphere. Climate change is measurable, and it’s happening at rate that is virtually unprecedented in human history, with extraordinary implications for biodiversity. In 100 years, Earth’s average surface temperature has increased 1.3°F. Eleven of the past dozen years rank among the 12 hottest on record. While the planet has been in a natural warming cycle for centuries, the current rate of warming is faster than anything detected for thousands of years.

“People are not seeing science; they are seeing what they see,” says Anthony Leiserowitz, a research scientist at the Yale University School of Forestry & Environmental Studies. Author of Communicating Climate Change, Leiserowitz conducted five regional and national studies to try to understand the root causes of the gap between what scientists understand and what the public and policymakers think.

“A major reason science doesn’t communicate well is that scientists tend to communicate in facts,” he says. “They say, ‘Here are the models, the uncertainties, the confidence levels.’ Most people don’t think analytically, they think experientially. And frankly, they don’t pay attention. Climate change gets much less coverage than celebrity gossip.”

That may be true, but there’s no uncertainty in what I’m seeing. A giant glacier–gone. A freshwater paradise–salty. Parks transformed–perhaps forever.

When Congress debated the Everglades park proposal in 1932, it was a new idea: a national park to be created not as a showplace for scenery, but as a shelter for threatened species. Now, the Everglades may gain the distinction of being the first park to be wiped off the map by climate change.

Ironically, things were starting to look better for this besieged park. State, federal, and Indian agencies have embarked on a 35-year, $11 billion effort to restore the greater Everglades. By elevating roads and tweaking the system of levees and canals, they hope to increase the fresh water coming down to the river of grass, and to reinstate some semblance of ecological balance.

Meanwhile, says Everglades superintendent Dan Kimball, the park has ambitious efforts under way to clean out invasives and restore ecosystems: It is burning back advancing hardwood trees, scraping up Brazilian peppers, and culling invasive Burmese pythons with the help of a beagle named Python Pete, whom I meet outside biologist Hallac’s office. The efforts are already showing success, says Hallac, with steady increases in populations of Florida panthers and American crocodiles.

But some, including the University of Miami’s Wanless, wonder whether the government is throwing money away, considering the likelihood that most of this low-lying park will eventually be under water.

Hallac counters that renewal efforts are more important now than ever. “Restoration can enhance the ability of populations and ecosystems to adapt or migrate in response to climatic shifts, buying them critical time while we work to limit climate change,” he says. “We need to get freshwater flows back and get these ecosystems healthy and robust, so that when the sea level comes up, they can handle the stress.”

Hallac shows me a map overlaying various sea-level scenarios on the topography of the park; they’re based on projections from the February 2007 report of the Intergovernmental Panel on Climate Change (IPCC). The IPCC has projected a sea-level rise of between 7 and 23 inches by 2100, which would erode beaches where sea turtles nest, and submerge tidal flats and inland freshwater marshes that serve as fish nurseries. If seas rise 23 inches, they could drown the park’s pinelands, one of the rarest ecosystems in South Florida.

Kimball refuses to see the glass as three-quarters empty. “Even if sea level rises 23 inches,” says Kimball, “we’ll still have half of our freshwater system.”

Problem is, 23 inches now appears to be a gross underestimate. Several new studies project that rising temperatures and melting ice will push sea levels up at least 3.3 feet by 2100. That’s significantly higher than the prediction in the IPCC report, which did not consider data collected after 2005. Since then, climatologists and glaciologists have developed a better understanding of the dynamics of accelerating ice flow. Ice sheets and glaciers, say scientists, are more sensitive than anyone had previously thought. Instead of melting slowly over centuries, they are susceptible to feedbacks, when melting leads to more melting and ice mass declines abruptly.

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