crushed basalt in farmland
Farmers around the world can help reduce greenhouse gas levels by mixing crushed volcanic rocks into fields. A recent global study identifies the humid, warm tropics as prime locations for this climate response strategy, showing where this approach could work best.
Researchers published in The Future of the World describe a potential global use of basalt in agricultural areas to enhance carbon dioxide retention. The method, known as advanced rock weathering, leverages the natural weathering of rocks to trap carbon dioxide in carbonate minerals. The goal is simple: accelerate a natural process in ways that also benefit farming and food security. When paired with ongoing emissions reductions, this approach could slow the pace of climate change.
It also offers benefits such as revitalizing depleted soils and countering ocean acidification.
Researchers note that spreading rock material on crops may present a safer option compared with other carbon removal methods. The study’s leadership notes the approach poses fewer risks while delivering additional advantages like soil restoration and reduced risks of ocean acidification, which could make it more socially acceptable.
New research highlights how crushed basalt, a rapidly breaking rock formed from cooled lava, can be applied across agricultural zones and which regions can most efficiently break up rock. The analysis outlines global farming areas where this approach could be most practical and impactful.
Experts see significant potential in this strategy. Some researchers emphasize that, while there are still questions to answer from a basic science perspective, the outlook is hopeful and invites practical exploration of implementation and markets.
crushed basalt in farmland
A new biogeochemical model simulates how crushed basalt on farmland around the world would capture carbon dioxide, testing the climate responsiveness of advanced rock weathering and identifying regions where the method could be most effective.
In simulations that modeled 1,000 fields worldwide under two emission scenarios from 2006 to 2080, results suggested these fields could absorb substantial amounts of carbon dioxide over the 75-year span. When extrapolated to all agricultural land, the approach could potentially capture a substantial share of global emissions over the same period.
Eliminating large amounts of carbon by 2100 is highlighted by climate projections
The latest climate reports emphasize the need to reduce hundreds of gigatons of carbon by the end of the century, in addition to cutting emissions. For global farmland, initial decarbonization estimates align with the lower end of what would be required to meet these targets, according to the study.
Because decomposition proceeds more quickly in hot, humid environments, the use of rocks in crops may be especially effective in tropical zones and in regions at higher latitudes within tropical belts. Farmers and investors are increasingly prioritizing basalt application in the tropics to maximize cost efficiency and carbon returns.
Natural retention of carbon dioxide
The model also shows that enhanced rock weathering remains effective at higher temperatures. Some other carbon storage approaches, such as organic carbon in soil, can be less reliable as the climate warms, making rock-based strategies appealing as a long-term option.
Experts note that advanced rock weathering is unusually resilient to climate change and tends to function similarly across moderate to severe warming scenarios, which supports its potential as a durable climate strategy.
Farmers already contribute large quantities of limestone to fields, a calcium carbonate rock used to supply nutrients and adjust soil pH. Shifting toward different rock types gradually could ease the transition to erosion-aware management on a scale that matches the rocks used and farmed lands, according to researchers.
Early applications of enhanced rock weathering have occurred on a small scale, and the next step is moving toward pragmatic implementation that can be scaled up.
Reference work: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EF003698
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