Andy Jarvis Models the Effect of Climate Change on World’s Top 50 Crops

Andy Jarvis has been using computer models to study how climate change will affect growth of the world’s 50 most important crops.

Image Credit: Clearly Ambiguous

Andy Jarvis has been using computer models to study how climate change will affect growth of the world’s 50 most important crops. Jarvis spoke with EarthSky from his office at the International Center for Tropical Agriculture in Colombia. He said that previous studies have focused primarily on wheat, corn and rice.


Andy Jarvis: Food security on a global level depends on a lot more than those three big crops. You’ve got things like barley, sorghum, and soybeans. Here in Latin America you’ve got coffee, for example.

Jarvis is a geographer. He’s been using data on rainfall, growing season and temperature–plus existing climate models–to figure out which crops will grow where as climate change progresses in this century. He spoke, for example, about Africa’s Sahel region.

These are some of the hottest areas of the world and so they lose a lot of options. Our models are showing it’s almost left really with the option of growing millet, which is used as an animal feed.

He said in other parts of Africa, increased rainfall might allow cash crops to be planted–such as tea and strawberries. And he reminded us that the impact of climate change is likely to vary from place to place around the globe. That’s why he hopes his study of the potential effects of climate change on so many different crops might be helpful to policy-makers.

He said his model looks at crops that are staples in various cultures.


For example, maize is predicted across many parts of Africa to lose its suitability. For hundred of millions of Africans, that’s their staple every day. We can breed new varieties of corn that will resist the warmer and drier conditions that many parts will receive in Southern Africa. I think between research and good policy we can confront these issues.

Jarvis’ agricultural models rely on existing climate models.

We use very simple characteristics in terms of climate to map out where that exists in the world today and then we project into the future using these global climate models. So, for example, beans need a three-month growing season. They need temperatures between ‘x’ and ‘y’ degrees, and they need a certain amount of rainfall.

Jarvis said that it takes a long time for changes to really occur on the ground.

So we see 2020 as the window right now directing our decisions. By 2050, things are a lot more drastic, a lot scarier, and that’s a very useful window for showing what would happen if we don’t do anything about climate change.

Jarvis explained that these kinds of changes will also affect northern latitudes. He said the corn belt of the United States will likely have to move northward. Jarvis’ collaborator on the project was his research assistant Julian Ramirez.


Our thanks to Andy Jarvis.

Written by Beth Lebwohl
Image Credit: Clearly Ambiguous.

Andy Jarvis is a Postdoctoral Fellow, based in the Land Use Project in the International Centre for Tropical Agriculture (CIAT) in Cali, Colombia. His specialties include conservation and use of wild relatives of agricultural crops, species distribution modeling, the impact of climate change on plant species, and adaptation strategies. In May of 2009, he won the Ebbe Nielsen prize, sponsored by the Denmark-based Global Biodiversity Information Facility (GBIF). The prize is awarded annually to one scientist for their innovative work in “bioinformatics” and “biosystematics”–the use of the latest computer technology in biodiversity research.

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