Ensuring science informs climate policy

In White House fellowship, Ann Marie Carlton seeks to curb agricultural greenhouse gas emissions

Scientists have warned politicians for decades that human emissions of carbon dioxide and other greenhouse gases are causing the climate to shift.

Some have listened; others haven’t. And Earth’s increasingly dire state is driving some scientists, such as Ann Marie Carlton, a UCI professor of chemistry, to try to make a more direct impact on environmental policy. She recently started a one-year stint at the White House Office of Science and Technology Policy as an American Association for the Advancement of Science Roger Revelle Fellow in Global Stewardship.

UCI Podcast: Bringing science to White House policymaking

The planet’s dismal prospects – fiercer wildfires, prolonged droughts, deadly heat waves – and the difficulty of implementing solutions have heightened the hurdles that experts face in communicating with policymakers. Carlton says that these officials often hear the bad news and immediately seek a second opinion, like patients who get a grim diagnosis from the doctor. This causes cascading delays in political action.

Ann Marie Carlton

Meet the Expert: Ann Marie Carlton, professor of chemistry

“The climate crisis is an existential threat, unlike any humans have previously experienced. I feel I have to try to do something right now to have any potentially relevant impact whatsoever for the people I love and care about.”

In comparison, earlier environmental problems were easier to solve, Carlton says. When UCI atmospheric chemist F. Sherwood Rowland – who won the Nobel Prize and for whom UCI’s Rowland Hall, where Carlton has her office, is named – co-discovered in the 1970s that chlorofluorocarbons were depleting the Earth’s protective ozone layer, the solution was to discontinue use of these compounds in aerosol spray cans and other products and industrial applications.

Halting climate change will be much more difficult.

“It means remaking our entire electrical grid across the United States. It means redoing our transportation systems. And that’s hard,” Carlton says.

Her scientific expertise is in how gases form particles in the atmosphere. Most of these particles start as gases and then undergo chemical transformations while in the air – acquiring dangerous properties. During her fellowship, she will explore policy methods for taming agricultural emissions of methane, ammonia and other gases.

In the United States, agriculture is the largest emitter of methane and nitrous oxide – potent greenhouse gases – and ammonia, which affects air quality. Nitrous oxide also destroys the ozone layer, like the chemicals banned in international agreements due to Rowland’s work. But these emissions are largely unregulated. 

Right now feels like this all-hands-on-deck moment, not just in American history, but in human history. The climate crisis is here, and it’s now, and it’s not going to get better unless there’s change.
- Ann Marie Carlton

Compared to the output from factories, which typically release pollutants from a single point, such as a smokestack, agricultural emissions are more diffuse, making them harder to regulate. At the same time, public perception of industrial activities is dim, while many people retain a positive image of farming.

“It’s less easy to put control equipment on a cow,” Carlton says. “I also think that no one wants an industrial smokestack in their backyard, but when we talk about agriculture, we all have this romantic, bucolic notion in our head, even though that’s not exactly what agriculture is in the United States, for the most part.”

The first step in drafting policies to tame this pollution will be collecting baseline information. 

“There’s a dearth of data concerning these emissions. How do you do a scientific assessment in the absence of data?” Carlton says. 

Her research group at UCI has correlated ammonia levels measured by satellites to concentrated animal feeding operations. Her initial findings suggest that density of animals – not number of animals – is most linked to ammonia levels. This kind of insight could help inform policies aimed at reducing the amount of ammonia released into the atmosphere.

Carlton’s focus on policy solutions comes from a deeply personal desire to ensure the livability of the planet.

“Right now feels like this all-hands-on-deck moment, not just in American history, but in human history. The climate crisis is here, and it’s now, and it’s not going to get better unless there’s change,” Carlton says. “And so I feel driven to do my part – because I want there to be change on a time scale that’s relevant for people I love and care about.”

– Aaron Orlowski, UCI