"With the UN Climate Change Conference still at the forefront of everyone's mind, it is vital that we investigate the safety, effectiveness, and benefits of methods such as enhanced weathering so we know what our options are," says David Beerling. (Credit: Bob Gundersen/Flickr)

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Is faster rock weathering an answer for CO2?

Speeding up the natural process that weathers rock could be a way to remove CO2 from the atmosphere, according to new simulations.

“Phasing down fossil fuel emissions remains a top priority, but we also need to better understand potential strategies for safely removing atmospheric CO2 to avert dangerous climate change,” says Lyla Taylor from the University of Sheffield’s animal and plant sciences department.

Lyla and colleagues used a complex modeling approach to investigate the large-scale effects of weathering and to find out how to accelerate the Earth’s natural CO2 removal system to counteract CO2 emissions and ocean acidification.

Weathering occurs when rainwater comes into contact with rocks under warm conditions, causing the rock to breakdown chemically. This process converts CO2 to bicarbonate, a natural neutralizer, which eventually drains away via rivers to the oceans.

[The planet may warm for centuries, even if CO2 shuts off]

Plants enhance this further by acidifying the soil particles around their roots. It helps if the surface of the rock particles is large, such as in silicate rock like volcanic rock basalt.

“We have shown that, in principle, rock weathering could indeed draw down atmospheric CO2 and could benefit coral reefs in the ocean,” says Taylor.

“The simulations we ran were idealized as they covered some of the world’s most ecologically sensitive terrestrial environments, however our evidence shows that the enhanced weathering strategy is definitely worth investigating further as it could play a significant role in offsetting the damage we are doing to the environment.”

‘So we know what our options are’

Ocean acidification is caused by the uptake of CO2 from the atmosphere, which leads to an ongoing decrease in the pH of the Earth’s oceans and has a range of possible harmful consequences, including coral bleaching, which leaves the organism vulnerable to disease.

The United Nations estimate ocean acidification could cost the global economy one trillion US dollars a year by 2100.

[How much money will carbon emissions burn up?]

“This study is important because deploying strategies for removing CO2 from the atmosphere are strongly embedded in climate stabilization policies but don’t yet exist,” says David Beerling, a professor at Sheffield and the study’s lead author.

“With the UN Climate Change Conference still at the forefront of everyone’s mind, it is vital that we investigate the safety, effectiveness, and benefits of methods such as enhanced weathering so we know what our options are. Detailed theoretical modeling like this is a good place to start,” he adds.

The study appears in Nature Climate Change. Additional researchers from the University of Bristol, University of California, Columbia University, and the Goddard Institute for Space Studies collaborated on the work.

Source: University of Sheffield

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