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Meet EPA Scientist Chris Clark, Ph.D.

EPA scientist Chris Clark, Ph.D. is working to assess the vulnerabilities we face from threats such as air pollution and climate change. Much of his work focuses on how we can adapt to build resilience in the face of these vulnerabilities.

Tell us about your background. EPA scientist Chris Clark

I am from the San Francisco Bay Area of California. I grew up an avid outdoors person, spending a lot of time outside hiking, backpacking, skiing, 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 and the complexity of natural systems. I went to graduate school for my Ph.D. in Ecology at the University of Minnesota where I focused on the impacts of air pollution from nitrogen deposition on terrestrial ecosystems. Afterwards I did a postdoc at Arizona State University researching how changes in plant biodiversity affected ecosystem functioning in the Inner Mongolian steppes of China and how urban air quality in Phoenix, AZ, affected local desert ecosystems.

What do you like most about your research?

I’m really motivated and excited about working on issues that are important to society today. I also really enjoyed the intellectual challenges in college of studying esoteric topics in physics, but I’m much more inspired about applied research to address issues that we face today. I want to help develop the science to support sound decision making to protect human health and the environment across air, land, and water. I also really enjoy working with so many different people across many different disciplines. Each of these issues are much more complex than any one researcher, scientist, or decision maker can address, so it takes a lot of people across many disciplines, 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?

I’m not much of a scientist groupie, I tend to be more awed by the ideas themselves than the people that came up with them. I’m weird like that. That being said, as a former physicist, I certainly would love to meet Einstein to know how he came up with many of his groundbreaking ideas given the isolation he was at the patent office in Bern. And Mendeleev, who developed the periodic table, it’s amazing to me how he came up with that given the limited knowledge that was available at the time. It’s that creative thread in science that is most inspiring to me.

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 on terrestrial ecosystems. None of these stressors occur in isolation in the real world, and so studying these factors in combination is important to understanding how ecosystems and the ecosystem services are affected by combinations of stressors.

Another area I focus on is how water resources and stormwater runoff in urban areas are impacted by climate change. 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?

It really depends on the project you’re talking about. For the atmospheric deposition work, I could see that helping to better understand which species and ecosystems are more at risk to air pollution. We’ve come a long way with the Clean Air Act and Amendments in reducing deposition, but it’s still above the levels at which many ecosystems are harmed. For the climate change work, it could help local municipalities better manage the changes in stormwater runoff that are likely to occur in the coming decades.

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. We learning more and more about the many benefits of diverse plant communities, including more growth and carbon sequestration, more resistance to invasion, more ecosystem services provided at higher levels, and higher stability through time of all these things that we care about. A less obvious effect is the impact on animal species. If the plant community changes, then some animal species that depend on a few plant species – called specialists – could be greatly impacted, but animals that are generalists may not be greatly affected so long as some other plant species comes in to replace the ones that are lost. We just don’t understand a lot about the substitutability of these species, let alone the ethical questions of treating species as substitutable in the first place.

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

Well if I were still a young lad I’d probably be a mountaineering guide, backcountry skier, or a travel writer. Now that I’m a dad in his 40’s, I’d probably own a small outdoor company somewhere or still be travel writing in some remote corner of the world. But, I have a pretty strong sense of civic duty, and I really enjoy working with others 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!


Editor's Note: The opinions expressed herein are those of the researcher alone. EPA does not endorse the opinions or positions expressed.