Too Late: Global Warming Irreversible

[DaMadFiddler]

http://www.npr.org/templates/story/stor ... d=99888903

Climate change is essentially irreversible, according to a sobering new scientific study.

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 become dangerous?"

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," Oppenheimer says.

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 reverse."

[Ex-Cyber]

Rush Limbaugh and Sean Hannity spinning this as "global warming scientists say we don't need to worry about emissions because we're doomed anyway" in 3... 2...

Anyway, as I've been saying for a while now, there are much more immediate economic and geopolitical concerns arising from our fossil fuel consumption. Even if global warming weren't a factor at all, it would still be a good idea to cut back our energy use (which tends to be inefficient) and move to more renewable sources (which are less economically entangled and less likely to start wars in the long term).

[Specially Cork]

This is great news. Now we don't have to waste time and money trying to fix it.

[DaMadFiddler]

This is great news. Now we don't have to waste time and money trying to fix it.

You may want to reread the following lines:

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 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.

[pavelbure]

i've noticed this global warming 1st hand. we had 1 day above freezing this past month.

[Specially Cork]

So...are we just trying to "slow global warming down a bit", or is there actually a way we can stop all these bad things happening in the future? If there is...what is that way? Reducing all human pollution to zero? As an average member of the polluting public, it's amazing how little info I have on this subject.

[Roofus]

This study would be far more credible if it hadn't been released during one of the coldest winters on record.

[not just souLLy now]

Regardless of the truth of global warming and the like, spewing shit into the air and using the earth's resources in an unsustainable manner is a bad idea whichever way you look at it.

I'm always amused by how many causes of global warming are thrown out there; farm animals, fossil fuels, china etc. When really there is only one cause: overpopulation. Until people begin to be comfortable with the idea that this is something that needs to be managed then any measures to slow climate change are just interim fixes.

I'm not saying I want to take away anyone's freedom to have kids but until we look at the problems we have honestly, how are we ever going to remedy them?

[Specially Cork]

I agree that overpopulation is a problem. I remember a website measuring my "carbon footprint" and telling me that "if everybody lived like you we would need 2.5 Earths" or something. Considering the normality of my responses to their survey, I didn't think it was really my lifestyle that was the problem, but rather the sheer number of people that in the future may live the same way.

[Lartrak]

i've noticed this global warming 1st hand. we had 1 day above freezing this past month.

Yep. Just like here in St. Louis, no murders for a week, so we clearly no longer have one of the highest murder rates of a major city in the US anymore.

[pavelbure]

i've noticed this global warming 1st hand. we had 1 day above freezing this past month.

Yep. Just like here in St. Louis, no murders for a week, so we clearly no longer have one of the highest murder rates of a major city in the US anymore.

yeah, because murder and weather are obviously related in your deranged world.

[az_bont]

i've noticed this global warming 1st hand. we had 1 day above freezing this past month.

Yep. Just like here in St. Louis, no murders for a week, so we clearly no longer have one of the highest murder rates of a major city in the US anymore.

yeah, because murder and weather are obviously related in your deranged world.

I think Lartrak's point was that you cannot point to a bit of anecdotal evidence based on a ridiculously small sample size as justification for an opinion where there is several orders of magnitude more evidence to the contrary.

[Kevin Beckman]

CO2 is actually a really weak greenhouse gas. Human contribution of CO2 into the atmosphere accounts for less than 5% of the total released a year. Water vapor causes more than 90% of the warming on Earth. How much affect do you really think we have?

[Ex-Cyber]

CO2 is actually a really weak greenhouse gas.

It's weak per gram/mole, but we aren't releasing petagrams of the other stuff each year.

Human contribution of CO2 into the atmosphere accounts for less than 5% of the total released a year.

Percentage of emissions is very different than percentage of concentration, and the overall rate of emission is a very different thing than the net change in concentration. Percentage of emissions alone doesn't say much of anything, and certainly doesn't account for the (in)ability of CO2 sinks to adjust to sudden changes.

Water vapor causes more than 90% of the warming on Earth.

Water vapor is responsible for a large proportion of the greenhouse effect, but the concentration of water vapor itself depends on temperature (concentrations above the equilibrium have a well-known habit of falling out of the atmosphere), so it's mostly magnifying changes from other causes rather than really being a cause itself.

[Specially Cork]

CO2 is actually a really weak greenhouse gas.

It's weak per gram/mole, but we aren't releasing petagrams of the other stuff each year.

Human contribution of CO2 into the atmosphere accounts for less than 5% of the total released a year.

Percentage of emissions is very different than percentage of concentration, and the overall rate of emission is a very different thing than the net change in concentration. Percentage of emissions alone doesn't say much of anything, and certainly doesn't account for the (in)ability of CO2 sinks to adjust to sudden changes.

Water vapor causes more than 90% of the warming on Earth.

Water vapor is responsible for a large proportion of the greenhouse effect, but the concentration of water vapor itself depends on temperature (concentrations above the equilibrium have a well-known habit of falling out of the atmosphere), so it's mostly magnifying changes from other causes rather than really being a cause itself.

But that makes it our fault, which is completely unacceptable.

[Kevin Beckman]

CO2 is actually a really weak greenhouse gas.

It's weak per gram/mole, but we aren't releasing petagrams of the other stuff each year.

It is weak. Period. Ice cores show many periods where CO2 levels rise or stay the same and temperatures still dropped.

Human contribution of CO2 into the atmosphere accounts for less than 5% of the total released a year.

Percentage of emissions is very different than percentage of concentration, and the overall rate of emission is a very different thing than the net change in concentration. Percentage of emissions alone doesn't say much of anything, and certainly doesn't account for the (in)ability of CO2 sinks to adjust to sudden changes.

CO2 levels were rising before we started pumping more into the atmosphere. As it has many times in Earths past.

[Ex-Cyber]

Ice cores show many periods where CO2 levels rise or stay the same and temperatures still dropped.

Who ever said that CO2 was the only variable? Lots of things have been different in the past. CO2 is, however, the major variable that's changing today. And it's changing very rapidly with respect to geologic time.

CO2 levels were rising before we started pumping more into the atmosphere. As it has many times in Earths past.

Show me any time in Earth's past that it's happened as quickly as it has in the past ~150 years. Rates of change matter.

[Wagh]

Really the only people who sit there and deny this stuff are fringies. I'm sorry it doesn't fit into your "world view" but no credible scientist is against this.