Carbon capture is a primary consideration for most climate scientists today. They know that avoiding the worst effects of global warming will require removing carbon dioxide from the atmosphere, not just reducing the amount that gets added. Atmospheric heating and acidification of oceans are cumulative processes. They took a long time to get started and will take a long time to stop. If we ceased all global carbon emissions today, average global temperatures would continue to spike and ocean acidification would continue unabated for decades to come.
We have often addressed proposed geo-engineering schemes that might help cool the earth — shooting sulfur dioxide clouds into the upper atmosphere, seeding the oceans with iron, placing an array of giant mirrors in geosynchronous orbit to reflect some of the sun’s rays back into space — but few are practical or even safe for human beings to consider.
Scientists at the University of Sheffield in the UK, together with colleagues from around the world, have released a new study today that suggests using granulated basaltic rocks left over from volcanic eruptions could provide several positive benefits to agriculture and the global community. Professor David Beerling, director of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and lead author of the new research, says, “Human societies have long known that volcanic plains are fertile, ideal places for growing crops without adverse human health effects, but until now there has been little consideration for how adding further rocks to soils might capture carbon.”
“This study could transform how we think about managing our croplands for climate, food and soil security. It helps move the debate forward for an under-researched strategy of CO2 removal from the atmosphere — enhanced rock weathering -= and highlights supplementary benefits for food and soils. The magnitude of future climate change could be moderated by immediately reducing the amount of CO2 entering the atmosphere as a result of burning fossil fuels for energy generation. Adopting strategies like this new research that actively remove CO2 from the atmosphere would contribute this effort and could be adopted rapidly.”
Some of the advantages of using basaltic rock in agriculture include improving the fertility of agricultural soils while slashing the amount of fertilizers and pesticides needed to grow crops successfully. Both are derived from oil stocks, which another reason to stop using them. Since farmers routinely add crushed limestone to their fields, all the infrastructure needed to distribute and apply crushed basaltic rock is already readily available.
Adding rock to fields doesn’t use up valuable arable land or require the use of more water — a commodity that is becoming increasingly scarce in many part of the world. The researchers believe any higher cost of adding basaltic rock to fields will be more than offset by the reduced amount spent on fertilizers and pesticides coupled with the extra market value of higher yields.
Dr. James Hansen, the much-vilified former NASA scientist who introduced the world to the now famous “hockey stick” graph several decades ago, is one of the authors of the new report. He points out that basaltic rock dissolves slowly in rainwater which increases the rate of natural weathering during with carbon dioxide is removed from the atmosphere. Less carbon dioxide means less acidification of the oceans — an important benefit that receives little notice in the press and requires more research to fully understand.
For more on this topic, please view the short video below, which features remarks from several of the researchers who have been pursuing this line of inquiry and who contributed to the latest report.