Rock Dust Applied to Farming Could Have a Major Positive Impact on Climate Change
A new study suggests that a radical change to agricultural practices involving basaltic rock dust could help extract substantial amounts of carbon dioxide emissions from the air.
The study, directed by lead researcher and author for the effort David J. Beerling, Director of the Leverhulme Centre for Climate Change Mitigation at The University of Sheffield, says that adding “crushed, fast-reacting silicate rocks to croplands” could have the effect of dramatically changing the absorption of CO from the atmosphere. It would also “improve
2 crop production, increase protection from pests and disease and restore soil fertility and structure” – major positive side effects.the means for doing this would be by adding minute rock grains to the cropland soils. Those rock grains would be basaltic, a kind that simultaneously naturally takes up CO and releases
2 nutrients essential to plants. The addition has the added value of not competing for land use and doesn’t increase the need for fresh water for crops. It could also minimize the need for agricultural fertilizers and pesticides so that in the process of adding these rock grains into the soil, the net cost of food production would lessen and farm productivity would go up.
The concept behind this process is something called “enhanced rock weathering.” The crushed silicate rocks proposed by the researchers for this effort could be added to any soil. Arable lands – the ones worked and planted annually – are the most obvious choice for the solution. They also happen to cover 12 million square kilometers around the world, or a net of 11% of the global land area.
In commenting about the research, Professor Beerling said that “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 CO removal from the
2 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 CO entering the atmosphere as a result of burning
2 fossil fuels for energy generation. Adopting strategies like this new research that actively remove CO from
2 the atmosphere would contribute this effort and could be adopted rapidly.”
Beerling’s colleague in the research and a co-author in the paper, Professor Stephen Long of the University of Illinois Urbana-champaign, said, “Our proposal is that changing the type of rock, and increasing the application rate, would do the same job as applying crushed limestone but help capture CO from the
2 atmosphere, storing it in soils and eventually the oceans.”
Professor James Hansen of Columbia University’s Earth Institute, also a co-author of the work, praised this kind of cutting-edge research, saying that “strategies for taking CO out of the atmosphere are
2 now on the research agenda, and we need realistic assessment of these strategies, what they might be able to deliver and what the challenges are.”
If this kind of proposal – to add basaltic rock dust into even a sizable minority fraction of the world’s croplands – could make a major difference in pulling CO out of the atmosphere, in the process, global
2 warming from greenhouse gas emissions might at least be slowed a bit from its current relentless pace.
The full paper on the study, entitled “Farming with crops and rocks to address global climate, food and soil security,” was published in the February 19, 2018, issue of Nature Plants.