by Megan Stoddard

Created on: September 06, 2010   Last Updated: September 07, 2010

We have now known for many years that human activity is contributing to climate change, perhaps even causing it outright. Carbon dioxide and other gases released by the widespread burning of fossil fuels have collected in earth’s atmosphere, eating away at the ozone layer that protects earth from damage by the sun’s rays while allowing life giving sunlight through.

The amassing of these gasses in the upper atmosphere has not only eaten away at the ozone layer, it is widely believed to have created what is known as a greenhouse effect: trapping the sun’s rays closer to earth, when without all those gases in the way, they would have bounced back into space. This in turn leads to climate change on a grand scale.

If we could reduce or eliminate our use of fossil fuels, we might have some hope of fixing climate change. Barring that, is it possible to continue using fossil fuels but somehow stop their damaging effects on the earth’s atmosphere?

Proponents of carbon capture and storage say that the answer is yes. This process entails separating carbon dioxide out from the gases generated when fossil fuels are burned and storing it somewhere, either buried deep in the earth or under the ocean. They claim that carbon dioxide stored underground would become part of the natural gas deposits already there, making it possible to reuse that carbon dioxide when the natural gas is pumped out.

The technologies necessary for carbon capture and storage already exist, but they are typically not being used that way. Carbon dioxide can be removed from fossil fuel before burning, in a process known as carbon scrubbing. It can also be removed from gas captured in a power station’s flue after the fuel has been burned. This is already done to remove certain fossil fuel-related pollutants from the air, such as sulfur.

Finally, if fossil fuel is burned in 95% oxygen instead of pure air (the average oxygen content of air is about 20%), the gas captured in the flue will be about 80% carbon dioxide, instead of the more typical 14%, allowing for easier capture and storage. This process, called oxyfuel combustion, is still being tested and not available on an industrial scale.

There are currently at least four carbon capture and storage programs in the world, and more are planned. However, carbon capture and storage still carries many uncertainties. It is prohibitively expensive, and it is expected to be at least 15 - 20 years before it becomes feasible on a grand

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