Abigail Swann makes a point of telling students what she's doing to reduce her own carbon footprint when teaching about potential climate change solutions—such as biking to work or eating less meat.

Swann, an assistant professor of atmospheric science and biology at the University of Washington in Seattle, said the strategy is just common sense, because "it certainly resonates with students when you show ... you make decisions in your own life that are consistent" with what she's teaching.

A study published a week ago in the peer-reviewed journal Climatic Change confirms Swann's instinct and concludes that climate researchers with low carbon footprints are seen as more credible than those who use a lot of energy in their personal and professional lives. Global warming denialists and those who know little about climate science sometimes accuse climate scientists of failing to practice what they preach. They call it hypocrisy, but scientists see it as a way of deflecting from the reality about the climate crisis and what it will take to solve it—cutting fossil-fuel emissions to near zero as fast as possible.

"Personal responsibility plays a role, but any real solution is going to require policy change at the highest level, including a price on carbon," Michael Mann, a climate scientist at Penn State University, said in a recent Facebook post after an online commenter said climate scientists should be "climate role models."

Still, many scientists said they were glad to see a formal study on the topic, and the results reflect their personal experiences. The paper "reinforces what my gut was telling me," said Julie Brigham-Grette, head of the geosciences department at the University of Massachusetts-Amherst. "I'm looking forward to sharing [it] with a lot of my colleagues."

Brigham-Grette often mentions her Prius and the solar panels on her roof when giving public talks—not just to show that she's following her own advice, but also because people need stories of positive change and "don't want to be hopeless," she said.

"Just telling people what to do [on energy use] is not good enough," said Corinne Le Quéré, a professor of climate science and policy at the University of East Anglia in Norwich, England. "People don't think with their brains," she said. "They think with their emotions and their perceptions."

Those perceptions don't always match the size of the problem.

"Numerically, we really need those big political solutions" to be truly effective, Swann said. But people "really want to know what they can do [personally]. If you're motivated enough to make these changes, hopefully it makes you interested in supporting the politicians or corporations interested in these solutions."

The study is the first to examine the credibility of climate researchers based on their own carbon footprints, said lead author Shahzeen Attari, an assistant professor at Indiana University in Bloomington, who studies human behavior and resource use. There have been studies on the perceived credibility of overweight doctors who give diet advice, for example, but nothing analogous for climate scientists, Attari said.

Researchers created an online survey describing various fictional climate scientists giving a talk about global warming and the actions that individuals can take to reduce carbon emissions. Some study participants received a version stating that the scientist used a lot of energy in his or her home. Others received a version about a scientist who conserved energy. Two other versions said nothing about the scientist's home energy use, but described how often they traveled by air: one scientist flew frequently and the other did so rarely.

About 5,000 people took the survey. The scientist who had a low carbon footprint at home was ranked as more trustworthy and more effective at inspiring participants to change their habits than the one who used more energy. That was the case for survey participants who said climate change was very important to them and for those who said the issue wasn't important. The scientist who rarely traveled by air got a smaller boost in perceived trust.

Survey participants may have cared more about home energy use because they understand that people often need to fly for work—a situation that's out of their control, Attari said. Residential and commercial buildings account for about 10 percent of U.S. carbon dioxide emissions.

While the study didn't examine the frequency of attacks on climate researchers based on their personal carbon emissions, Attari said she's experienced it herself and has heard anecdotes from scientists who study the natural and social aspects of global warming.

Shortly after Attari's study was published, Anthony Watts, a prominent climate contrarian, published a blog post purporting to show aerial photos of six climate scientists' homes, including Mann's. Watts accused the scientists of hypocrisy because none of the houses had rooftop solar panels (though one property had panels on the barn). Watts also posted photos of the solar panels on his own roof and his electric car.

A few days later, DeSmogBlog (a website that debunks climate denial efforts) contacted the scientists featured on Watts'' blog. Three of them said they did have solar panels on their roofs that did not show up in the satellite images. Mann said he pays extra to get his electricity from wind power.

The Problem With Flying

Most of the increase of carbon dioxide in the atmosphere has been caused by burning fossil fuels for electricity and transportation. Aviation accounts for just a few percentage points of the world's greenhouse gas emissions, but for many researchers and others, reducing air travel is a sticking point. Its carbon footprint is growing quickly, and there are limited technologies for decarbonizing the industry--though emissions can be offset by purchasing carbon credits. Those who attended last December's international climate talks in Paris were offered carbon credits for their flights: it cost $1.75 to neutralize the emissions of a New York-to-Paris round trip flight.

"I often propose to my fellow colleagues that we have carbon-neutral online video meetings rather than all flying somewhere to meet," Katharine Hayhoe, an atmospheric scientist at Texas Tech University, said in an email. "Half the time, I just get blank stares."

Swann, the UW scientist, said it's particularly challenging for early-career researchers like her who need to share their work at conferences to boost their chances of getting tenure.

Le Quéré, the University of East Anglia scientist, said she's at a point in her career where she can miss certain events. She now flies only to meetings on international climate policy and those that support international development. When she's invited to speak at other conferences, she offers to join via video feed and is frequently turned down as a result.

Last year, the Tyndall Centre for Climate Change Research—a partnership of eight British universities directed by Le Quéré—published a working paper encouraging climate scientists to create a research culture that minimizes carbon emissions, particularly those related to travel. It also launched a process for scientists at the center to track and reduce their own aviation-related emissions.

We still have a promotion structure in academia that's all about traveling to meet people in person, Swann said, and that cultural expectation "hasn't caught up with this idea [that] we should be flying less."