Arthur Gueneau: The Impact of Climate Change on Agriculture

Jan 01, 2011
Arthur Gueneau: The Impact of Climate Change on Agriculture

As Arthur Gueneau leaves MIT to explore greener pastures, he’s leaving his mark on the agricultural world with a new model he’s named after himself—well, kind of. The CLM_AG model—the product of his thesis—adds an agricultural component to the Community Land Model (CLM) currently woven into the Joint Program’s IGSM.

“In the beginning I was taking CLM and putting A-G after it and people said, ‘Oh A-G for agriculture.’  Well, actually, it’s my initials, but that works too,” Arthur said of his new creation.

While few will remember the true meaning behind the name, the model itself will be a lasting feature of the Joint Program’s work. CLM_AG measures the impact of climate change on crop water stress and irrigation. Unlike in the past where the IGSM used a standardized crop formula, Arthur’s additions to the model allow it to look at the behaviors of different crops in different regions. For example, corn needs more water than cotton, and wheat is usually rain fed. These behavioral differences cause these crops to be impacted by climate change in different ways. The CLM_AG model is also more consistent in its equations and faster to run than the previous CliCrop model the program had been using.

Arthur’s thesis used CLM_AG for two main purposes. First, he used the model, along with the MIT IGSM-CAM climate model, to find out what impact climate change would have on the world’s irrigation systems by 2050, both with and without mitigation policy. From this, Arthur found that climate change surprisingly made it easier for some areas of the world to grow healthy crops because as it gets warmer evaporating water vapor could cause more rain. But, Arthur warns, there is a lot of uncertainty from model to model and region to region. This led Arthur to the second aspect of his thesis – an in-depth look at uncertainty in one specific region: Zambezi, Africa. Arthur used 400 different variations of the model to learn which crops would have a greater risk of suffering from a lack of water. He found, for example, that corn in Zambezi may require up to 15 percent more water than it used to. But, Arthur warns, there is still a high level of uncertainty.

How do you plan policy for that?

“It depends on what you want to do,” Arthur says. “Do you want to do something that’s resilient? That means plan for the worst scenario because if the worst case happens and you’re not prepared then you’re in really bad shape. Or, do you want to be economically efficient? Then you should plan somewhere in the middle…You could also be the guy who’s hiding behind his desk with his hands covering his eyes saying ‘Oh, but there’s still a 10 percent chance that it doesn’t change.’”

The key, Arthur says, is being able to adapt to climate change.

“The whole point is to be flexible. If you’re planning an irrigation system, you should plan in the middle but keep the option open to be able to add a second pipe or raise the dam.”

Arthur’s ongoing research on this topic will take him to Washington, DC, where he will be studying the impacts of climate change on agricultural policies at the International Food Policy Research Institute. As he departs for this adventure, Arthur says he will always remember that progress takes collaboration—a lesson he learned from the Joint Program.

“This whole program is built on a system where groups of people who would have never talked to each other if it was up to nature come together,” Arthur says, “I’ve learned from this that everything is a system. Everything is connected. If you don’t go outside your specific focus and talk to other people who are studying the same thing in a different way, you’re missing the point.”