Opinion A Danish climate scientist has published a paper criticising carbon sequestration - the idea of dealing with CO2 emissions by stuffing the greenhouse gas away into underground or deep-sea storage where it can't affect the atmosphere.
Professor Gary Shaffer of the Niels Bohr Institute at the University of Copenhagen was already mildly well-known for his suggestion that the world's fossil fuel resources should be saved up in order to fight the next ice age in 100,000 years' time using targeted global warming.
Now the prof has done some long-term analysis into the consequences of massive carbon sequestration, and he doesn't seem happy with what he's found. According to a statement issued by the Niels Bohr Institute, sequestration amounts to creating "a burden for future society... in line with that of long term management of nuclear waste".
“The dangers of carbon sequestration are real," insists Shaffer. "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.”
The prof says that deep-ocean sequestration is a definite no-no, as it means "grave problems for deep sea life" right off and the carbon gets back into the atmosphere quite fast, too.
The more commonly advocated plan of pumping CO2 into disused oil or gas fields doesn't meet with Shaffer's approval either. He points out that these subterranean/subsea reservoirs are scarcely leak-proof.
"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," he argues.
According to Shaffer's analysis, geological sequestration is only worthwhile if a leakage rate of less than one per cent over a thousand years can be obtained. Otherwise the various issues of acidification, re-sequestration, sea level rises etc outweigh the benefits.
The professor's research can be read here by subscribers to the journal Nature Geoscience. ®