Climate change could increase productive farmland more than 30% – and boost carbon emissions 177 gigatons

Future farming in regions that were previously unsuitable for agriculture could significantly impact biodiversity, water resources, and greenhouse gas emissions worldwide. Lee Hannah of Conservation International’s Betty and Gordon Moore Center for Science in Arlington, Virginia, and colleagues present a new analysis of these risks in the open access journal PLOS ONE.

As Earth’s climate warms, some regions at higher altitudes and latitudes may become more suitable for farming, potentially helping to feed a growing global population. However, recent research suggests these agricultural “frontiers” pose threats to wildlife, water resources, and other environmental factors. Such risks are poorly understood at the global level.

To help clarify these risks, Hannah and colleagues conducted a first-of-its-kind global modeling analysis of climate change-driven shifts in crop suitability and their environmental effects. The analysis incorporated the predictions of 17 global climate models and enabled assessment of different regions’ future suitability for 12 key crops, including corn, sugar, and cotton.

The modeling results suggest that climate change will increase the global amount of land suitable for key crops by more than 30 percent, mostly in upper latitudes of the Northern Hemisphere and in mountains around the world. Farming these frontiers could pollute downstream water resources that serve 1.8 billion people. It could also decrease biodiversity in tropical mountains; the predicted frontiers overlap 19 global diversity hotspots, as well as critical bird habitats.

In addition, farming of agricultural frontiers has the potential to release up to 177 gigatons of carbon naturally stored in frontier soils into the atmosphere. This amount is equivalent to more than 100 years’ worth of present-day carbon dioxide emissions in the U.S., and its release could accelerate global warming.

The new findings could help shape efforts to manage farming in agricultural frontiers, such that communities can benefit from new farmland while mitigating the environmental consequences.

The authors add: “In a warming world, there will be new opportunities and challenges in the north. This work highlights how we must approach the idea of developing new farmland very cautiously and be extremely mindful of potential negative environmental impacts.”

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O artigo foi publicado originalmente em GLP.