Food production is big. If farmers fail to adapt to climate change we can expect to see more land being turned over to agriculture, in order to keep up with food demand. With this in mind, David Lobell, from Stanford University, US, and colleagues used a model of global agricultural trade to investigate the co-benefits of helping farmers adapt to climate change, thereby avoiding some of the emissions associated with land-use change.

Running their model to 2050, they show that an investment of $225 bn in agricultural adaptation measures can be expected to offset the negative yield impacts associated with predicted temperature and rainfall changes. But that’s not all – the model revealed that this investment would also save 61 million hectares from conversion to cropland, resulting in 15 Gtonnes carbon-dioxide equivalent fewer emissions by 2050.

"I don't think any of us expected the mitigation benefits to be as big as they were," said Lobell, whose findings are published in Environmental Research Letters (ERL). "We had a hunch that they would be big enough to be an important co-benefit, but the fact they were often big enough to rival other mitigation activities was surprising."

So what kind of agricultural adaptation measures might produce this effect? "We focused in the study on research investments, which relate to the development and deployment of new technologies, for example developing new seeds that have better disease resistance or drought tolerance, or new soil management techniques to conserve water," explained Lobell. "Of course it's hard to know how successful particular investments will be, but the track record on overall returns to agricultural investment is strong."

Lobell and his colleagues also found that the co-mitigation benefits of such investments were highly location-dependent. Modelling a scenario of agricultural adaptation focused only on sub-Saharan Africa and Latin America resulted in much smaller mitigation potentials and higher per-tonne costs.

"These results indicate that although investing in the least developed areas may be most desirable for the main objectives of adaptation, it has little net effect on mitigation because production gains are offset by greater rates of land clearing in the benefitted regions, which are relatively low yielding and land abundant," the authors wrote. "Adaptation investments in high yielding, land-scarce regions such as Asia and North America are more effective for mitigation."

Human activities are currently estimated to produce around 40 billion tonnes of carbon-dioxide equivalent every year. Model results indicate that agricultural adaptation measures would prevent around 350 million tonnes of carbon-dioxide emissions annually – equivalent to around 1% of total global emissions. "We are not proposing this as a strategy by itself to mitigate climate change," Lobell told environmentalresearchweb. "Instead, we are saying that the mitigation benefits are significant enough to merit consideration when deciding where to make investments."