Climate Change Brings Risk of More Extinctions – washingtonpost.com

Around the world, scientists have found that climate change is
altering natural ecosystems, making profound changes in the ways that
animals live, migrate, eat and grow. Some species have benefited from
the shift. Others have been left disastrously out of sync with their
food supply. Two are known to have simply disappeared.

If warming continues as predicted, scientists say, 20 percent or more
of the planet’s plant and animal species could be at increased risk of
extinction. But, as the shrinking habitat at Blackwater shows, the bad
news isn’t all in the out years: Some changes have already begun. “This
is actually something we see from pole to pole, and from sea level to
the highest mountains in the world,” said Lara Hansen, chief climate
change scientist at the World Wildlife Fund,
a private research and advocacy group. “It is not something we’re going
to see in the future. It’s something we see right now.”

The temperature increase behind these changes sounds slight. The world
has been getting warmer by 0.2 degrees Fahrenheit every decade, a U.N. panel found this year, in part because of carbon dioxide and other human-generated gases that trap heat in Earth’s atmosphere.

By nature’s clock, the warming has come in an instant. The mechanisms
that helped animals adapt during previous warming spells — evolution
or long-range migration — often aren’t able to keep up. Scientists say
that effects are beginning to show from the Arctic to the Appalachian Mountains. One study, which examined 1,598 plant and animal species, found that nearly 60 percent appeared to have changed in some way.

“Even when animals don’t go extinct, we’re affecting them. They’re
going to be different than they were before,” said David Skelly, a Yale University
professor who has tracked frogs’ ability to react to increasing warmth.
“The fact that we’re doing a giant evolutionary experiment should not
be comforting,” he said.