Many also opposed the idea of such technologies becoming a substitute for tackling the root causes of climate change. Respondents who took part in surveys and workshop discussions feared that they might take too long to develop, and expressed concern that the basalt dust could affect ocean ecology. From research carried out in the United Kingdom and the United States, it is clear that CO 2-removal strategies could face scepticism. The project team also studied how members of the public would react to such technologies ( E. This will bring costs down, increase carbon uptake and make more efficient use of mined materials. And although rock will need to be mined, the Sheffield team is rightly calling for an inventory of free, suitable waste rock from existing mining operations. That said, such costs are in line with competing technologies that could be used to pull CO 2 out of the atmosphere. By contrast, Beerling and his colleagues estimate that enhanced rock weathering will cost between $80 and $180 per tonne of CO 2. The current price of carbon on the European Union’s emissions trading system is less than €28 (US$31) per tonne. Moreover, mining rock on industrial scales, pulverizing it and spreading the dust on crop fields will not be cheap. But we need to be confident that there are no harmful consequences to land and sea, and any potential effects would need to be monitored carefully. And the alkaline content that runs off to the oceans could, in theory, counteract acidification, helping to protect corals and other creatures that are threatened by rising atmospheric CO 2 levels. Some of this might be beneficial: rock dust of the right variety could bolster desirable plant communities, for example. Tinkering with the geochemical cycle will inevitably alter ecosystems in soils, rivers and even oceans. And there are potential questions for regulators, too. Researchers must answer a host of pressing questions about the economic costs and environmental impacts. Costing the Earthīut, like many promising technological fixes, spreading basalt dust across the world’s agricultural fields could prove more complicated than it first seems. Moreover, the machines that are required to spread basalt dust on fields already exist: farmers use them to treat soils with limestone. The approach, if successful, could enable high-emitting countries such as the United States and China to remove some of the carbon they have pumped into the atmosphere in recent decades. These are encouraging developments at a time when governments around the world are struggling to meet their climate commitments. The early results also indicate that adding basalt boosted yields in these and other crops. The application of 20 tonnes of basalt dust to a half-hectare UK plot boosted CO 2 removal by 40% compared with that seen on an untreated plot, and by 15% in another trial, which spread dust over oil-palm plantations in Malaysia. The authors have told Nature that preliminary results suggest the theory is holding up. The team is also carrying out field trials in four countries - the only such trials yet. Removal of atmospheric CO2 by rock weathering holds promise for mitigating climate change The upper limit is more than 5 times the annual emissions of the United Kingdom, and akin to offsetting emissions from around 500 coal-fired power plants. According to their calculations, doing so would remove between 0.5 billion and 2 billion tonnes of CO 2 from the air each year. The researchers modelled what would happen to atmospheric carbon if basalt dust was added to agricultural lands in the world’s biggest economies, including Brazil, China, the European Union, India, Indonesia and the United States. The team’s results provide the most detailed analysis yet of the technical and economic potential of this approach - and some of the probable challenges, including gaining public acceptance. The idea of scaling up this process to remove carbon has been considered for some three decades. In the process, atmospheric CO 2 is converted into stable bicarbonates that dissolve and then flow into rivers and oceans. This is a continuously occurring natural phenomenon in which carbon dioxide and water react with silicate rocks on Earth’s surface. In this issue, David Beerling, a biogeochemist at the University of Sheffield, UK, and his colleagues explore a strategy to enhance rock weathering ( D. Credit: Nick Hatton/AlamyĬould spreading basalt dust on farmers’ fields help to remove atmospheric carbon? A large multidisciplinary team of scientists is confident it could, and that doing so could boost crop yields and soil health at the same time. Equipment used to coat agricultural fields with limestone could also be used to spread basalt dust.
0 kommentar(er)
