Boffin dubs global warming 'irreversible'

Economies may rise and fall every few decades or so, but at least the hard work we've put into global warming is "irreversible" on the human time scale.

That's according to research from a team of US environmental scientists published today in the journal Proceedings of the National Academy of Sciences.

The report claims that even if all carbon emissions could somehow be halted, the CO₂ changes to Earth's surface temperature, rainfall, and sea levels will keep on truckin' for at least a millennium.

"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 study author Susan Soloman. "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."

Oh, for the job security of a carbon dioxide molecule.

The scientists say the oceans are currently absorbing much of the planet's excess heat, but that heat will eventually be released back into the air over the course of many hundreds of years.

Carbon concentrations in the atmosphere today stand at about 385 parts per million (ppm). Many environmental scientists have a vague hope of stabilizing CO₂ in the atmosphere at 450ppm if major changes in carbon emissions are instituted post-haste.

But according to the study, if CO₂ peaks at 450-600ppm, the result still could include persistent dry-season rainfall comparable to the 1930s North American Dust Bowl in zones including southern Europe, northern and southern Africa, southwestern North America, and western Australia.

If carbon dioxide in the atmosphere reaches 600ppm, expansion of warming ocean waters alone (not taking into account melting glaciers and polar ice sheets) could cause sea levels to rise by at least 1.3 to 3.2 feet (0.4 to 1.0 meter) by the year 3000.

The authors claim to have relied on many different climate models to support their results. They said they focused on drying of particular regions and thermal expansion of the ocean because observations suggesting humans are contributing to climate change have already been measured.

So remember readers: an extra hour to your car ride today may help make it a warm, sunny day at the London coral reef for your grateful descendants no matter what those UN hippies try. ®