[LINK] Global Warming Is Irreversible, Study Says
brd at iimetro.com.au
Fri Jan 30 21:13:44 EST 2009
If global warming is irreversible, maybe we should stop tinkering with
irreverent/irrelevant suggestions and start looking at survival strategies.
Global Warming Is Irreversible, Study Says
by Richard Harris
All Things Considered,
January 26, 2009
Climate change is essentially irreversible, according to a sobering new
As carbon dioxide emissions continue to rise, the world will experience
more and more long-term environmental disruption. The damage will
persist even when, and if, emissions are brought under control, says
study author Susan Solomon, who is among the world's top climate scientists.
"We're used to thinking about pollution problems as things that we can
fix," Solomon says. "Smog, we just cut back and everything will be
better later. Or haze, you know, it'll go away pretty quickly."
That's the case for some of the gases that contribute to climate change,
such as methane and nitrous oxide. But as Solomon and colleagues suggest
in a new study published in the Proceedings of the National Academy of
Sciences, it is not true for the most abundant greenhouse gas: carbon
dioxide. Turning off the carbon dioxide emissions won't stop global warming.
"People have imagined that if we stopped emitting carbon dioxide that
the climate would go back to normal in 100 years or 200 years. What
we're showing here is that's not right. It's essentially an irreversible
change that will last for more than a thousand years," Solomon says.
This is because the oceans are currently soaking up a lot of the
planet's excess heat — and a lot of the carbon dioxide put into the air.
The carbon dioxide and heat will eventually start coming out of the
ocean. And that will take place for many hundreds of years.
Solomon is a scientist with the National Oceanic and Atmospheric
Administration. Her new study looked at the consequences of this
long-term effect in terms of sea level rise and drought.
If we continue with business as usual for even a few more decades, she
says, those emissions could be enough to create permanent dust-bowl
conditions in the U.S. Southwest and around the Mediterranean.
"The sea level rise is a much slower thing, so it will take a long time
to happen, but we will lock into it, based on the peak level of [carbon
dioxide] we reach in this century," Solomon says.
The idea that changes will be irreversible has consequences for how we
should deal with climate change. The global thermostat can't be turned
down quickly once it's been turned up, so scientists say we need to
proceed with more caution right now.
"These are all ... changes that are starting to happen in at least a
minor way already," says Michael Oppenheimer of Princeton University.
"So the question becomes, where do we stop it, when does all of this
The answer, he says, is sooner rather than later. Scientists have been
trying to advise politicians about finding an acceptable level of carbon
dioxide in the atmosphere. The new study suggests that it's even more
important to aim low. If we overshoot, the damage can't be easily
undone. Oppenheimer feels more urgency than ever to deal with climate
change, but he says that in the end, setting acceptable limits for
carbon dioxide is a judgment call.
"That's really a political decision because there's more at issue than
just the science. It's the issue of what the science says, plus what's
feasible politically, plus what's reasonable economically to do,"
But despite this grim prognosis, Solomon says this is not time to
declare the problem hopeless and give up.
"I guess if it's irreversible, to me it seems all the more reason you
might want to do something about it," she says. "Because committing to
something that you can't back out of seems to me like a step that you'd
want to take even more carefully than something you thought you could
brd at iimetro.com.au
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