Earth Institute Profiles

Ruth DeFries

Denning Professor of Sustainable Development; Professor of Ecology, Evolution, and Environmental Biology

Ruth DeFries

What can satellite imagery tell us about the impact of humanity’s transformation of the landscape on climate and ecosystems? A lot, according to Ruth DeFries, ecosystems expert, Denning Professor of Sustainable Development, and professor of ecology, evolution, and environmental biology at Columbia University and the Earth Institute’s Center for Environmental Research and Conservation (CERC).

DeFries joined the Columbia faculty in 2008 and, in the last three years, she has been awarded a Fulbright award and memberships to the National Academy of Sciences and the American Association for the Advancement of Science, and, in September 2007, the MacArthur “genius” fellowship – one of the most prestigious awards in the world. One would be hard-pressed to find an environmental researcher with more accolades in such a short period, but DeFries is not slowing down. Columbia and the Earth Institute are thrilled to have her on board as a member of one of the strongest teams of sustainable development researchers and educators in the world.

As an environmental geographer, DeFries is credited with transforming the way scientists analyze the impact of land cover change. One of her main projects is using satellite imagery to track changes to the planet’s vegetation and their impacts on climate and ecosystems. She and her team have done this by using mapping techniques that can cover large areas at repeated time intervals, an advancement over observations on the ground that can cover only small areas at single points in time. These changes they have seen in Earth’s vegetation have widespread effects, including emissions of greenhouse gases that cause climate change, loss of habitat for other species, and potentially the movement of disease vectors.

In DeFries’ own words regarding the importance of considering this large spatial and temporal scale, "Humans have been transforming the landscape for at least 10,000 years to grow food and create settlements.  This transformation has been especially rapid in the last few decades, with many negative repercussions for the planet.  Our role is to provide input for sustainable decisions about land use."

DeFries’ work is based on the understanding that changes in land use need to balance positive benefits such as food production and potentially negative consequences for climate and habitat. With a focus on deforestation in the tropics and its effect on carbon emissions, DeFries’ research has included the rapidly changing landscapes of central Africa, South Asia, Southeast Asia and the Brazilian Amazon.

It is this work that can largely be attributed for her receipt of the genius grant. The MacArthur Foundation states that the datasets compiled from this method have “significantly changed the scale and focus of ecosystem research, enhanced her and other researchers’ ability to make more plausible projections of future climate change, and contributed to understanding how human activities are altering habitat needed to conserve biodiversity.”

In an interview with the University of Maryland press after her induction into the National Academy of Sciences, DeFries had this to say:

“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.”

DeFries is also actively involved in linking her research to the policy-making process – an integral part of the Earth Institute’s mission to connect research to practical application.  For example, her work has contributed to the international policy discussion underway to reduce greenhouse gas emissions from tropical deforestation.

DeFries has also worked at the National Research Council and at the prestigious Indian Institute of Technology in Mumbai, India. She received her B.A. from Washington University in St. Louis in 1976 and her Ph.D. from Johns Hopkins University in 1980.