Global Warming May Be Irreversible

A new paper published by a leading researcher says many effects of climate change are already irreversible. Susan Solomon, a leader of the International Panel on Climate Change and a scientist with National Oceanic and Atmopheric Association (NOAA) said even if carbon emissions were stopped, temperatures around the globe will remain high until at least the year 3000. And if we continue with our current carbon dioxide emissions for just a few more decades, we could see permanent “dust bowl” conditions.

Solomon defined “irreversible” as change that would remain for 1,000 years even if humans stopped adding carbon to the atmosphere immediately. As carbon dioxide emissions rise, the planet will be undergo more and more long term environmental disruptions which will persist even if and when emission are brought under control.

The report says temperatures around the globe have risen and changes in rainfall patterns have been observed in areas around the Mediterranean, southern Africa and southwestern North America. Warmer climate also is causing expansion of the ocean, and that is expected to increase with the melting of ice on Greenland and Antarctica.

A recent NASA article said observations have confirmed rising temperatures in Antarctica over the past 50 years in not only the Antarctic Peninsula, but in western Antarctica as well.

In a teleconference, Soloman said this is not just another pollution problem. “We’re used to pollution problems being something we can fix, smog, — we can cut back and things will get better later. Or haze, we think it will go away pretty quickly.”

This is true for gases like methane and nitrous oxide, but not for CO2. “People have imagined that if we stopped emitting carbon dioxide that the climate would go back to normal in 100 years or 200 years,” said Solomon. “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.”

This is because the oceans are currently soaking up a lot of the planet’s excess heat, as well as some of the carbon dioxide from the atmosphere. The carbon dioxide and heat will eventually start coming out of the ocean. And that will take place for many hundreds of years.

The scientists say that once the global thermostat once it has been turned up, its extremely difficult to turn it back down.

Solomon said sea level rise is a much slower thing to happen, that it will take a long time, but we will lock into it based on the peak level of C02 we reach this century.

So, should we just give up? Are we doomed? “It seems like this is even more reason to do something about it,” Solomon said. “When you are committing to something you can’t back out of, you need to proceed even more carefully than when it’s something you can reverse….I don’t think that the very long time scale of the persistence of these effects has been understood.”

The paper is published in Proceedings of the National Academy of Sciences.

Sources: PhysOrg, NPR