Burying the greenhouse gas carbon dioxide, a byproduct of burning fossil fuels, has been mooted as one geoengineering approach to ameliorating climate change. To be effective, trapping the gas in geological deposits would be for the very long term, thousands of years.
Now, a team in Brazil, writing in the International Journal of Global Warming has reviewed the risk assessments for this technology and suggests a lack of knowledge means we should be cautious of turning to this method rather than finding sustainable ways to reduce emissions at their source.
Maísa Matos Paraguassú of the Federal University of Bahia and colleagues there and at Salvador University explain how the scientific consensus suggests that anthropogenic carbon dioxide entering the atmosphere underpins the greenhouse effect. Rising concentrations of the gas could lead to an uncontrollable rise in global average temperatures with concomitant effects on our planet’s climate and devastating local effects in extreme cases.
Numerous proposals have been put forward to sequester carbon dioxide from emissions sources, such as power stations the electricity-generating turbines within which are powered by fossil fuels, and vehicle exhausts. But, ultimately, there need to be global repositories within which the gas can be stored indefinitely in sublimed or mineralized form.
Of course, the sequestration, conversion and transportation of trapped carbon dioxide have its own energy and emissions costs. Nevertheless, if sufficient of this greenhouse gas can be held within geological formations, and then there might be a way to tame the potentially runaway effect of climate change that would ensue if atmospheric levels continue to rise.