Carbon sequestration could be ticking time bomb, says scientist

Posted by Emma Woollacott

Carbon capture and storage could be as risky and hard to manage as the storage of nuclear waste, according to a Danish scientist.

Given that there's much too much excess carbon to sweep under the rug, many people have turned to the nearest thing: sequestering it in deep-sea or underground storage facilities. The European Union plans to invest billions of Euros in carbon sequestration over the next ten years.

But according to Gary Shaffer, professor at the Niels Bohr Institute, and leader of the Danish Center for Earth System Science, calculations show that undersea storage of CO2 would cause serious problems for marine life - and in any case, he says, the CO2 would quickly find its way back into the atmosphere.

"CO2 sequestration has many potential advantages over other forms of climate geoengineering," says Shaffer.

"However, one should not underestimate potential short and long-term problems with leakage from underground reservoirs. Carbon in light form will seek its way out of the ground or seabed. The present situation in the Gulf of Mexico is a poignant reminder of that."

Shaffer made long model projections for a number of sequestration/leakage scenarios. His results show that leakage of the stored CO2 could bring about serious warming of the atmosphere, large sea level rises and oxygen depletion, acidification and elevated CO2 concentrations in the ocean.

Underground storage could be more effective, he says, but only if a CO2 leakage of one percent or less per thousand years can be obtained.

Managing the leakage could be a burden for future society on a par with the long term management of nuclear waste, he says.

"The dangers of carbon sequestration are real, and the development of this technique should not be used as an argument for continued high fossil fuel emissions," warns Shaffer.

"On the contrary, we should greatly limit CO2 emissions in our time to reduce the need for massive carbon sequestration and thus reduce unwanted consequences and burdens over many future generations from the leakage of sequestered CO2."