How Climate Change Will Impact Animals
The threats to wildlife on the African island of
Madagascar is manifold: rampant deforestation that has
stripped most of the island of its original forest cover, leaving a
wasteland; a human population that is growing at 3% a year,
straining natural resources and hunting animals for food,
especially Madagascar's emblematic lemurs; extractive
industry, including a nickel mine not far from a national park that
could become the world's biggest.
There's another danger that's invisible, but may be more
dangerous than the others put together: climate change. Global
warming will do to wildlife what it may do to humans. As the
climate changes, animals may be forced to move out of the habitats they're accustomed to — like
human refugees. "Global warming is something that all conservationists are worried about," says
Russell Mittermeier, the president of Conservation International. "It has the possibility to undo a lot of
the work we've done."
While the impact of climate change on human populations is likely to be dire, we're pretty good
at adapting to change overall. Animals, however, are not. When their habitats change irrevocably
— when the rain forest dries up or cool mountains in tropical zones heat up — animals may simply go
extinct. A recent study in Science demonstrates how that can happen. Robert Colwell, an evolutionary
biologist at the University of Connecticut, analyzed data from nearly 2,000 species of plants, insects
and fungi in the tropics, where organisms often lack the ability to escape warming temperatures by
going north or south; instead, they have to go up in elevation to find cooler temperatures. Colwell found
that as populations in lowland areas move up, they tend not to be replaced.
That means that we may see a reduction in overall biodiversity and what scientists call "species
richness." Meanwhile, species that already live at the highest elevations have no place to go, except
perhaps to extinction. Case in point: the Golden Toad, which lived in the high-altitude cloud forests of
Costa Rica and suddenly went extinct. Its disappearance may be due in part to warming, which made
its habitat unlivable.
The toad may be the first animal whose extinction scientists will link to global warming, but it
certainly won't be the last. Last year, the U.N.'s Intergovernmental Panel on Climate Change
estimated that if global temperatures increase more than two to three degrees Farenheit above current
levels — which seems quite possible, given current trends in carbon emissions — up to one-third of
the species on Earth could be at risk for extinction. "We're already seeing nature react badly to climate
change," says Larry Schweiger, the president of the National Wildlife Federation. "We're changing the
rules of the game."
For one thing, the grand design of conservationism is to create reserves, protected areas like
national parks where wildlife can live free from the impact of human populations. That strategy has
been overwhelmingly successful, but conservationists now fear that global warming could make those
reserves meaningless, if animals that are accustomed to a different climate can't survive in them.
"We're used to focusing on protecting real estate," says Schweiger. "Now we have to be able to
make sure animals can move to safe areas."
First, conservationists say, we need to do everything we can to slow carbon emissions and
reduce the impact of climate change. "That's priority number one," says Mittermeier. But some degree
of warming is inevitable, so conservationists have to prepare. That means creating not just reserves,
but safe nature corridors that would allow wildlife to migrate in the face of rising temperatures. Another
method is to try to connect existing reserves through reforestation — a technique already underway in
Madagascar, where the government is looking to vastly increase the total amount of protected land.
What's certain is that we need to act. If we don't, says Schweiger, "Climate change could undermine
the conservation work of whole generations."
I need it simplified