The University of Texas at Austin- What Starts Here Changes the World
Services Navigation


A Matter of Degrees: More than half of Earth's wild species already affected by climate change, biologist finds


Camille Parmesan grew up in Houston, where oil was not only the city’s business, it was her family’s business.

Her mother, Dorothy Johnson Parmesan was a geologist for Magnolia Oil Co., and Parmesan’s sister, Anne Gafford, now works as an oil company geologist.

Camille Parmesan
Dr. Camille Parmesan

Parmesan also took the path of science, but as a biologist. An assistant professor of integrative biology at The University of Texas at Austin, she studies butterflies.

In one of those one-thing-leads-to-another stories, the pursuit of butterflies led her to study climate change.

She studied how it affected the Edith’s checkerspot, the butterfly that’s her specialty. That led to research on how other species are affected by climate change around the world.

Several groundbreaking studies later, Parmesan has become an authority on the impact climate change is having on the planet’s plants and animals.

She had been studying the Edith’s checkerspot when, in 1992, she responded to NASA’s Mission to Planet Earth program.

“I devised a project to look for response to global climate change by looking at the whole species range all the way from Mexico to Canada and asking the really simple question, ‘Are we seeing it shifting its range?’” she says. “And NASA said, ‘Sure, go for it.’ And gave me three years funding to do this.”

She found that the butterfly had abandoned habitats in Mexico and southern California and that it was moving farther north and to higher altitudes.

That led to other climate change studies, culminating in the 2003 paper published in Nature that showed climate change is altering how and where hundreds of species of plants and animals across the globe are living.

She and co-author Gary Yohe, an economist at Wesleyan University, analyzed data from studies of almost 1,700 species.

Worldwide impact

Camille Parmesan touches a butterfly as it rests on a flower

Butterfly rests on a flower
Watch video of Dr. Parmesan by Environmental Science Institute.

Photos courtesy ESI

They found that more than 50 percent of wild species have been affected by climate change. Habitats have moved farther north and to higher elevations. Some species were breeding earlier in the year and some plants were blooming earlier.

“That’s a huge number, to think that half the wild species are showing a response to 20th century climate change is just a much bigger number that I think any biologist expected,” Parmesan says.

The report has been considered the strongest statistical evidence that global warming—influenced by trapped greenhouse gasses such as carbon dioxide from cars and factories—is having an impact on a wide scope of species and regions.

Parmesan last fall co-authored a study of North American species for the Pew Center on Global Climate Change. Its conclusions were that more than half the studies analyzed provided strong evidence of a direct link between global warming and changes in the behavior of species in the continental United States and Alaska.

“The message from the report is that human-driven climate change has affected species all across the U.S., from new tropical species arriving in Florida to changes in the basic functioning of ecosystems in Alaska,” Parmesan says. 

“Climate change has had enormous impact on wild species,” she adds. “It obviously is something we’re going to have to take into consideration in terms of conservation practices. You know we have to think of climate change as one of the threats, causing endangerment.”

Her climate change studies have thrust Parmesan into work with international policy groups.

She is the chair of a World Conservation Union task force on climate change. Part of its mission is to assess the losses under different climate scenarios.

“We are going to get species going extinct,” she says. “That’s obvious, but it’s a matter of how do you minimize it given that our mental attitude and our whole set of conservation principles and management guidelines are not set up to cope with the fundamental shifting climate.”

With the sun behind clouds, the butterfly spreads its wings to gather as much heat as possible
This series of images offers a look at why temperature is an important consideration for where a butterfly calls home. Parmesan took the images with a thermal-imaging camera in June 2003 in the Alps of southern France.

With the sun behind clouds, the butterfly spreads its wings to gather as much heat as possible.

A matter of degrees

The task force wants to quantify what the impact might be under the scenarios of temperature increases.

“What we’re starting to work on is hopefully going to put some numbers to that to be able to show how much better is it to keep down to that minimum scenario versus to let it go up to a higher scenario,” she says. “To give stronger motivation to keep the change down to minimum levels.”

Many believe that losses can be kept to a minimum if the average temperature rises just 2 degrees centigrade by 2090, according to Parmesan.

“But if we start going up the four- and six- and eight-degree scenarios we could really be looking at massive loss of almost all species that conservation biologists have been working so hard to try and save,” she says.

Parmesan said the goal is to begin work to keep climate change to lower levels and to show what might happen if that doesn’t happen.

“We’re trying to convince the policy makers that it’s worth putting effort into keeping it at that lower level,” she says.

In this photo, the butterfly’s temperature is too cool for it to fly
In this photo, the butterfly’s temperature is too cool for it to fly.

While the studies have been influential, it’s not the kind of work Parmesan became a biologist to do.

“We had to slog through paper after paper,” she said about the study she and Yohe conducted, “sometimes with obscurely written data sets. Very rarely were the data nice and clean.”

Back with the butterflies

Parmesan would rather be in the field chasing butterflies.

“My work is very dirty. I’m out in the mountains, camping out in a tent for months at a time,” she says. “And it’s wonderful. I don’t think I could ever go back to working in a sterile lab environment after working in the field because you get to know the pulse of the species you’re working with, you get an intuition for them. You get to know what makes them happy, what they like, what they don’t like.”

She plans to return to the field, which means the Alps and tundra of Scandinavia to track butterflies.

She’ll be looking at pairs of species that are similar in their habitats, ecologies and what they eat. But one of the species has responded to climate change and the other hasn’t.

“I want to tease apart why one of them is so affected by temperature, by thermal constraints, and the other is not,” she said. “And how will that help us predict who might be most sensitive in the next 100 years.”

Bringing message home

Here, the butterfly begins to warm up as the sun comes out. The heat is beginning to radiate into the wings from its body
Here, the butterfly begins to warm up as the sun comes out. The heat is beginning to radiate into the wings from its body.

As she works on the international stage, Parmesan also is working to increase awareness about climate change in Texas.

She says she faces uninformed, if not skeptical, audiences and she comes prepared with charts and graphs showing 70 million years of the planet’s climate history.

“When I give a seminar, I show graphs, which is something you’re told never to do to the general public,” Parmesan says. “Bull. They want to see the data.”

The data, she said, do the job without much help from her.

“Because I’m a Texan I know you don’t do a salesman job on Texans,” she said. “I just step back and say, ‘You come to your own conclusion. I’m just going to show you what we know.’”

Parmesan has already won over two stalwart climate change skeptics: her mother and sister.

“I’ve had so many arguments with them about climate change,” she said. “By now they’re finally converted.”

Tim Green
Office of Public Affairs

Photo of Dr. Parmesan: Marsha Miller


Office of Public Affairs

P.O. Box Z
Austin, Texas
78713-7509

512-471-3151
Fax 512-471-5812


  Updated 2014 October 13
  Comments to utopa@www.utexas.edu