EPA Research

Meet EPA Scientist Chris Clark, Ph.D.

Building Resilience to Climate Change

EPA scientist Chris Clark, Ph.D. is working to assess the vulnerabilities we face in the threat of a changing climate. Much of his work focuses on how we can adapt to build resilience in the face of these vulnerabilities.

Image of EPA Scientist Chris Clark

Tell us about your background.

I grew up in California, in the Bay Area. I was an avid outdoors person, spending a lot of time outside hiking, backpacking, and rock climbing. I graduated from the University of California-Davis with a double major in Physics and Environmental Science. Toward the end of college, I studied abroad in Costa Rica and fell in love with ecology. I went to graduate school for my Ph.D. at the University of Minnesota where I focused on the impacts of nitrogen deposition on terrestrial ecosystems. Afterwards I did a postdoc at Arizona State University researching how changes in biodiversity affected ecosystem functioning in the Inner Mongolian steppes of China and how urban air quality in Phoenix, AZ, affected local ecosystems. 

What do you like most about your research?

I work with a lot of different people in a lot of different disciplines, and it’s inspiring and fun to work with so many smart, dedicated people on such complex problems. Each problem is much more than any one researcher, scientist, or decision maker can address, so it takes a lot of people, a big community. I really like that because I’m always learning and exchanging ideas.

When did you first know you wanted to be a scientist?

I’ve always been curious about the world around me. When I reached high school, I was seeing a lot of environmental debates on the ozone hole and climate change, and I didn’t feel like I understood the subject well enough to contribute in any meaningful way. I felt like if I wanted to participate in this conversation going on around me, I needed to know more about it. That’s why I went into science.

If you could have dinner with any scientist, past or present, who would you choose and what would you ask him or her?

As a former physicist, I think it would be amazing to meet Albert Einstein. I would just enjoy having a conversation with him and learning about his life.

What are you working on now?

Nitrogen occurs naturally throughout our environment and often stimulates plant growth. But too much of anything can be a problem, and having the right balance in an ecosystem is important. Many of our daily activities, such as burning fossil fuels and fertilizing crops, can cause levels of nitrogen in our environment to rise to levels that mess up a lot of natural processes and communities. In my current work, I’m looking at how atmospheric nitrogen that is deposited on land impacts the biodiversity of plants and animals living there.

I’m also researching the interactive effects among nitrogen deposition and climate change. From an ecosystems point of view, we want to know how plant species are impacted, and what happens afterward in terms of the benefits people and communities get from ecosystems—“ecosystem services” such as carbon sequestration, nutrient cycling, and preventing soil erosion.

Another area I focus on is how water resources in urban areas are impacted by climate change and severe storms. We are developing recommendations on how green infrastructure - things like rain barrels, rain gardens, and permeable pavement - can be used to reduce those impacts.

What impact do you see your research having?

If we want to effectively manage our environment, we need to understand what the impacts have been in the past so that we can prevent biodiversity loss in areas that haven’t been affected yet.  There are broad swaths of the country that are probably not affected yet, while others have been affected greatly. We are taking the lessons learned from studying the affected areas and transferring them to the ones that haven’t been hit yet to prevent future decline.

What are some basic problems with biodiversity loss?

When you have widespread changes in the distribution of plant species across a landscape, you can have big changes in the how ecosystems function. For example, there could be big changes in plant root or leaf biomass, which in turn will greatly affect soil stability and photosynthesis.

Those effects are all pretty straightforward. A less obvious effect is the impact on animal species. If plants die out, the animals that depend on those plants to survive can die out with them. That could affect the animals you want to hunt or keystone species (see side bar, What are keystone species) that keep an ecosystem stable and working. We want to avoid the losses that are still preventable.

If you weren’t a scientist, what would you be doing?

The indulgent part of me would want to be a mountaineering guide or a travel photographer. But, I really like working on a team to improve the state of the world, so if I weren’t a scientist I would probably be part of an NGO that focused on energy and the environment. How we extract and use energy underpins a lot of the challenges and opportunities we face in the environmental domain.

Any advice for students pursuing a career in science?

I would tell them to go for it. There are a ton of interesting, important questions that haven’t been answered and we need all the help we can get. Be curious, keep at it, and have fun!