First-time visitors to the Great Barrier Reef might think they've swum into an Impressionist painting. The reef—a living kaleidoscope of thousands of species, many unique, threatened, or both—has no equal on Earth, which explains its magnetic appeal to people the world over. Some 2 million tourists flock to northeast Australia every year to experience the wonder of the Coral Sea, and they inject $5.5 billion into the country's economy in the process.
Now imagine one possible future. It's 2050, and rising sea temperatures caused by global climate change have killed the symbiotic algae that live inside the coral and sustain it. Their loss has left huge swaths of reef bleached and lifeless. Runoff from coastal farms, meanwhile, has clouded the water with sediment and poisoned sea grasses with pesticides. Almost all the fish are gone, and those that remain are hounded by boatloads of sunscreen-slathered tourists. This worst-case scenario is extreme but not impossible. Tourism, pollution, and coral bleaching already threaten the reef. A report commissioned by the Queensland government and the World Wide Fund for Nature in 2004 predicted that 95 percent of the reef's living coral could die by midcentury if ocean temperatures there rise by 2.7 degrees F, as scientists predict.
The Great Barrier Reef is just one of a growing number of unique places around the world that are under siege by forces both local and global. From Antarctica to the Everglades, from Venice to the mountainous forests of East Africa, climate change and encroaching civilization imperil many of the world's most distinctive destinations. The list of dangers includes rising sea levels, pollution, development, changing weather patterns, even the presence of well-meaning visitors. And what's at stake encompasses many of the world's natural and cultural treasures. Like species, places can become endangered. They can also be saved. Already some local rescue efforts are paying off, while preserving other places will require nothing short of a concerted planetwide effort.
"If you look hard enough, you can uncover some sort of looming threat in just about any destination," says Kimberly Lisagor, coauthor of Disappearing Destinations: 37 Places in Peril and What Can Be Done to Help Save Them, published last month by Vintage Books. Climate change is the most pervasive danger, she says, and also one of the toughest to fight. Some iconic places are literally melting away. Climatologists predict the glaciers of Mount Kilimanjaro, Africa's tallest peak and a linchpin of Tanzania's nearly $1 billion tourism industry, will be gone in less than 15 years. Glacier National Park in Montana may have to find a new name if its glaciers disappear before midcentury as they're expected to. And in Antarctica, which ice researcher Stephen Ackley of the University of Texas-San Antonio calls "the last pristine ecosystem on Earth," the disappearance of seasonal sea ice is every bit as much a threat to penguins and seals there as it is to polar bears and other species in the Arctic.
The rising sea. Less ice means more water, and since many of the world's great cities are close to the coast, rising oceans may soon be lapping at their gates. Picture Venice as an archipelago of rooftop islands, with scuba divers swimming down its canals. A combination of sinking land, worsening storms, and rising sea levels is already nudging things in that direction. The seasonal high tides locals call acque alta now flood the city's famous lagoon a hundred times a year instead of six or seven, as they did a century ago. Salt water flowing in from the Adriatic Sea is causing centuries-old brick walls to crumble. "The city is being eaten by water," says Anna Somers Cocks, chairman of the nonprofit group Venice in Peril. "Ecologically, it's completely artificial, like New Orleans. It will survive as long as we want it to survive." The Italian government is hoping that a controversial $7 billion system of movable floodgates, nicknamed "Moses," will save the city. Any allusion to the parting of seas is entirely intentional. When finished in 2012, the project will consist of 78 gates, each 98 feet high, that can be raised or lowered from the seabed in response to changing tides. Whether this will just postpone the inevitable—a slow-motion surrender to the rising sea—remains to be seen.