Science

The Telegraph

Volcanic ash should be spread across the seabed as a cheap way to capture carbon dioxide and tackle climate change, British scientists have said. A new study from the University of Southampton found that judicious use of volcanic ash can help sediments boost carbon capture. The ocean is the most significant store of carbon in the world, and capturing the element to reduce the amount of carbon dioxide in the atmosphere is one of the most important aims in the fight to tackle climate change. The research, published in Anthropocene, modelled the impact of spreading volcanic ash from a ship to an area of ocean floor to help amplify natural processes which lock away CO2 in the seabed. They found the technique has the potential to be cheaper, technologically simpler and less invasive than other techniques to remove harmful gases. "As a result of overwhelming evidence, politicians have begun to take steps towards incorporating emissions reductions into policies, such as in the 2015 Paris Agreement with its long-term goal of ensuring that global average temperatures do not exceed 2°C above pre-industrial levels. "However, it is becoming clear that to avoid the worst impacts of climate change, active greenhouse gas removal (GGR) will be required," explained study co-author and University of Southampton Professor of Geochemistry, Martin Palmer. Sediments on the seafloor as calcium carbonate and organic carbon are an important store of carbon, and the scientists found that supplementing them with volcanic ash boosted their carbon sequestering properties. Most volcanoes lie close to the oceans, and every year millions of tonnes of volcanic ash falls into them and settles to the seafloor. It is also a cheap method to capture carbon. Scientists worked out ash spreading could cost $50 (£39) per tonne of CO2 sequestered. Further work needs to be done on the impact of spreading ash on the seabed, scientists warned, before it is rolled out as a policy. Researchers need to figure out whether the method would impact sea life, but they said the discovery is encouraging. Other ways to capture carbon include restoring peat bogs and planting more trees, as well as improving soil health. This method could be hugely encouraging as unlike some other methods, the approach is simply an augmentation of a naturally occurring process, it does not involve expensive technology and it does not require repurposing valuable agricultural land. "One of the ways oceans lock away CO2 is by storing it in sediments on the seafloor as calcium carbonate and organic carbon. In our work, we discuss how this natural process may be augmented by artificially adding ash to oceans," said Jack Longman, lead-author and former Post-Doctoral Research Assistant at the University of Southampton.