A Conversation with UM's Ruth DeFries, Newly Elected to the National Academy of Sciences

Professor Ruth DeFries, who has a joint appointment in the department of geography and the Earth System Science Interdisciplinary Center, was recently elected to the National Academy of Sciences. Election to the Academy is made in recognition of distinguished and continuing achievements in original research and is considered one of the highest honors in American science and engineering.

DeFries researches deforestation and other changes that humans are making to the Earth's land surface. Using data from satellites and field work, DeFries studies how these changes affect climate, biodiversity, water quality and other factors that determine the Earth's habitability.

DeFries is co-author, with Cheryl Simon Silver, of One Earth, One Future: Our Changing Global Environment , published in 1990. In 2004, she edited the book Ecosystem and Land Use Change, published by the American Geophysical Union. DeFries co-teaches the undergraduate course "Cause and Implications of Global Change," which integrates physical, chemical, geological and biological sciences with geographical, economic, sociological and political knowledge. She also teaches upper level undergraduate and graduate classes.

Newsdesk talked with Professor DeFries about her research and her election to the National Academy of Sciences.

How did you feel when you learned you had been elected to the National Academy of Sciences?

DeFries: Stunned! It's definitely an honor, but there are so many other people who deserve this honor. Certainly, it is very gratifying that research in the area of land cover and land use change is being recognized. I also feel a little overwhelmed because it is a big responsibility.

What do you mean?

DeFries: It's an opportunity to raise the profile of land cover research, promote working with scientists from other fields, and develop dialogue with the policy community.

I also think (my election) shows that it is possible to do good science and still keep your personal priorities. I worked part time for many years when my children were young, because raising them was my priority. I have to thank John Townshend (geography department chair). He hired me and gave me the opportunity to do that.

Can you tell us more about your work and on what you currently are working?

DeFries: I study land cover change and what people are doing to the landscape. I look at the role of land cover changes in climate, in terms of effects on the carbon cycle, as well as the implications for conservation and other services people derive from ecosystems. Satellite data allow us to see these changes.

Most of my work is in the tropics. What we are seeing in parts of the tropics is continuing deforestation, in many cases for large scale conversion of land to mechanized agriculture. Land use change not only has repercussions for climate, but also for animal and human habitats that can include reduced biodiversity, loss of watershed protection and impacts on human health.

Of course, there is always a balance, or a trade off, between economic benefits of land use changes and the costs of these changes. Understanding the cost side of the equation requires not only measuring the immediate impacts of land use and land cover change, but also understanding climate and biological systems and how they are affected by these changes over longer periods of time.

What do you think is the scientific consensus about climate change or global warming, as it is commonly called?

DeFries: There is a wide consensus that we are experiencing climate change and that it will accelerate in the future. The question is how human society will adapt to the changes that are occurring. Knowing how we need to adapt means that we need to understand the climate system so we can have the best, most accurate projections of the effects of climate change.

What do you like best about what you do?

DeFries: I love working with students. Students are so creative and they really want to make a difference. And I love getting out in the field and really being able to see the changes on the ground and how people interact with their environment.

In the 15 years that you've been at the university what are some of the changes that you've seen?

DeFries: Well, one would be the increasing quality students at College Park . It really shows in the classroom, and it's fun to see! The opportunities to carry out research with scientists from different disciplines is also expanding, and that is what we need to do to truly contribute to the challenges society is facing with climate and land use change.

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