WASHINGTON (AP) — Hard-to-predict sudden changes to Earth’s
environment are more worrisome than climate change’s bigger but more gradual
impacts, a panel of scientists advising the U.S. government concluded.
The 200-page report by the National Academy of Sciences
looked at warming problems that can occur in years instead of centuries.
The report repeatedly warns of potential “tipping points”
where the climate passes thresholds, beyond which “major and rapid changes
And some of these quick changes are happening now, said
study chairman James White of the University of Colorado.
The report said abrupt changes such as melting ice in the
Arctic Ocean and mass species extinctions already have started and are worse
It said thousands of species are changing their ranges,
seasonal patterns or in some cases are going extinct because of human-caused
climate change. Species in danger include some coral; pika, a rabbitlike
creature; the Hawaiian silversword plant; and polar bears.
At the bottom of the world in Antarctica, the melting ice in
the west could be more of a wild card than originally thought. If the massive
ice sheet melts, it may happen relatively rapidly and could raise world sea
levels by 13 feet, but researchers aren’t certain how soon that may occur.
However, the report had what researchers called “good news.”
It said two other abrupt climate threats that worried researchers likely won’t
be so sudden, giving people more time to prepare and adapt.
Those two less-imminent threats are giant burps of undersea
and frozen methane, a super-potent greenhouse gas, and the slowing of deep ocean
currents. That slowdown is a scenario that would oddly lead to dramatic coastal
cooling and was featured in the 2004 movie, “The Day After Tomorrow.”
Study co-author Richard Alley of Pennsylvania State
University compared the threat of abrupt climate change effects to the random
danger of drunk drivers.
“You can’t see it coming, so you can’t prepare for it. The
faster it is, the less you see it coming, the more it costs,” Alley told the
Associated Press. “If you see the drunk driver coming, you can get out of the
The scientists said the issue of sudden changes is full of
uncertainties, so the world can better prepare by monitoring places such as
Antarctic and Greenland ice sheets more.
But because of budget cuts and aging satellites, researchers
have fewer measurements of these crucial indicators than they did a few years
ago and will have even fewer in upcoming years, study co-author Steven Wofsy of
Harvard University said.
The panel called on the government to create an early
“The time is here to be serious about the threat of tipping
points so as to better anticipate and prepare ourselves for the inevitable
surprises,” said the report by the research arm of the federal government, which
enlists independent scientists to look at major issues.
Donald Wuebbles, a University of Illinois climate scientist
who wasn’t part of the academy study, called it important, especially the call
for better warning systems. However, outside scientist Michael Mann of Penn
State said he doesn’t see the need for a new warning system.
“The warning is already there, loud and clear,” Mann said in
an email. “The changes we are seeing in the Arctic are unprecedented in
thousands of years, and they are already having a catastrophic impact on human
civilizations, animals and ecosystems there.”
In a separate study, published in the journal PLoS One, former NASA climate
scientist-turned-activist James Hansen argued that the countries of the world
have set the wrong goal in its fight against global warming.
World leaders have set a goal of trying to keep warming to
another 2 degrees from now, but Hansen said that would blow past tipping points
and give Earth a “dangerous level” of global warming.
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