“Irreversible” climate change no argument for giving up

A new study of the long-term effects of CO2 emissions on climate by a group of US and European scientists suggests that despite efforts to combat climate change, the planet could still be feeling the impacts of global warming in the year 3000.

That’s because although the concentrations of carbon dioxide in the atmosphere might decline as emissions are limited, the oceans, which are absorbing heat, will eventually release that heat back into the atmosphere resulting in renewed warming. Scientists have argued that while sobering, the new report is no argument for giving up on controlling climate change.

The study “Irreversible Climate Change Due To Carbon Dioxide Emissions” is published in the current issue of Proceedings of the National Academy of Sciences

It can be downloaded here.

Professor Martin Manning of Victoria University’s Climate Change Research Institute comments:

“The leader of the new research, Dr Susan Solomon, co-chaired the Intergovernmental Panel on Climate Change’s assessment of the science completed in 2007. The IPCC report pointed out that around 20% of the CO2 being added to the atmosphere from the use of fossil fuels is expected to stay in the atmosphere for tens of thousands of years.

“The importance of the new paper is that it shows the implications of this persistence of CO2 for climate, particularly for drought and sea level rise. To determine what are virtually irreversible effects, the authors use a suite of climate models to consider the amount of climate change that still exists in the year 3000 following a CO2 rise to different levels during this century and then stopping emissions.

“Peak CO2 levels close to or a little above current values are still having an effect on climate in the year 3000. But the real concern, is that if we take CO2 much above these levels then there are regions in all continents that, for thousands of years, would face major droughts which the authors of the study suggest could be worse than the ‘dust bowl’ era in North America in the 1930s.

“I see two policy implications of the new work. First, the UN Framework Convention on Climate Change, agreed by virtually all countries, recognises threats of irreversible damage as of particular concern and that clearly involves CO2 more than other greenhouse gases. Second, we should be very cautious about suggestions that CO2 could be allowed to go above a safe threshold in the hope that we could bring it back down later. It doesn’t look like the planet would cooperate in that.”

To speak to this or other climate change experts contact the SMC on 04 499 5476 or smc@sciencemediacentre.co.nz