PLEA Network

17 February 2016, Climate News Network, Carbon capture could be costly and risky. Attempts to remove carbon dioxide from the atmosphere and store it safely are all potentially costly gambles with the current technology, scientists say. There’s bad news for those who think that carbon dioxide can be removed from the atmosphere and stored deep in the Earth’s rocks. Even if carbon capture is possible, sequestration in the rocks is fraught because the gas can find multiple ways to escape, according to a report by a team from Penn State University, US, in the International Journal of Greenhouse Gas Control. Carbon dioxide is not the only greenhouse gas, but it is the one that drives global warming. It escapes from power station chimneys and motor exhausts. Back in the 18th century, the air contained 280 parts of CO₂ per million, but now the level has just reached 400 parts per million. In the same period, the average global temperature has risen by 1°C and will go on rising, to make climate change an increasing hazard. Switch to renewables Last December, 195 world leaders agreed in Paris to take action aimed at containing warming to – if possible – 1.5°C. Climate scientists warn that the world must switch to solar power, wind and other renewable sources. But some think that if the exhaust emissions could be trapped and stored, humans would be able to get a bit more value from their fossil fuel investments. Others see it as the only way of avoiding 2°C of warning − the agreed international safety limit prior to the Paris climate summit. The problem is that nobody is confident that carbon can be captured on a sufficient scale. “Removal of CO₂ will be expensive and is currently unproven at the scale needed – so it would be much better to reduce emissions as rapidly as possible” Some projects have been abandoned, and others suggest that the problem is that not enough has been spent on the research. But the Penn State team looked at a different aspect: whether CO₂ could be buried and forgotten. So they tested laboratory reactions that involve sandstone and limestone – two of the sedimentary rocks found most often in geological strata – and water and carbon dioxide. Read More here