On the outside, it looks like an ordinary refrigerator, but inside it recreates the winter climate of the mountains of California. At -1.5 degrees, in this refrigerated chamber, thousands of caterpillars of a creature as delicate as it is special for science (Edith's checkerspot butterfly) (Euphydryas editha) hibernate. We are more than 9,000 kilometers from their natural habitat, as they only live in Mexico, the USA, and southern Canada. However, thanks to the appropriate facilities and, above all, the experience, patience, and knowledge of the American ecologist Camille Parmesan (Houston, 1961), these butterflies brought from California are being bred in a pioneering laboratory in southern France. "We have to be very attentive to them, they are my babies," she summarizes as she leads us to a bright room to show us several live specimens.
She places one in my hand so that I can appreciate up close all the beauty and extraordinary colors of this iconic butterfly for ecology. And it is thanks to her that Camille Parmesan demonstrated for the first time that wild species are modifying their geographical distribution in response to climate change. Following that milestone for environmental science, achieved in the mid-90s, came other research that showed that thousands of plants and animals were experiencing the same impact. A true detective work for which the BBVA Foundation has awarded her this year with its Frontiers Award in Climate Change and Environmental Sciences, an award she will receive this Thursday in Bilbao.
The main stage of her current research is the Theoretical and Experimental Ecology Station (SETE), of which she is the director. These facilities, located in the town of Moulis, in the Midi-Pyrenees region, belong to the French National Center for Scientific Research (CNRS) and allow her to conduct numerous experiments mimicking natural conditions. Alongside her is her husband, the British scientist Michael Singer, considered an authority in the field of butterflies, an insect he has been breeding since he was a child.
In a jar, they keep thecocktailwith which they feed the butterflies born in captivity: a mixture of organic honeys from wildflowers living in high areas of the Pyrenees, a pinch of sea salt to provide minerals, and some add a touch of amino acids. "Michael has developed a recipe over the years, and this one in particular contains thyme, lavender, and rosemary honey, although others can be used," Parmesan explains. Wild butterflies take very small amounts of nectar a hundred times a day, so what they do here is give them a larger amount three or four times. If they eat with that frequency, she assures, "they remain more fertile and healthy. To prevent them from dying, just feed them once."
And they always do it themselves. "I don't let anyone else take care of them because every time I've asked students to take care of the butterflies, they have killed them," she says with a laugh but seriously. "Now I have fantastic equipment to keep them well. I have them hibernating as if they were in the snow, and I can leave them like that for months." Her meticulously designed system also simulates the climate of the Californian mountains in summer - "dry, sunny, and rarely rainy." For those that have already been born, she keeps them cool in transporters called habitats that she stores in other refrigerators, with temperatures between five and 10 degrees, so they can live longer.
Edith's checkerspot butterfly only lives in North America: "It has cousins in Europe, but they are not as interesting," Parmesan asserts, who graduated in Zoology and earned her Ph.D. in Biology from the University of Texas. "It is very unique, even among butterflies, which are already very sensitive to human activities that harm biodiversity. And since they are beautiful, people love to observe and collect them, so we have very good records of them."
In the early 90s, as she was finishing her Ph.D., there was more talk about climate change: "In the meteorological data, they still did not see a significant warming trend, although they expected it based on basic theory and physics knowledge," she recalls. The scientist obtained a grant launched by NASA in a call called 'Mission to Planet Earth' to investigate the impacts of climate change. Parmesan thought to herself: "I know a lot about Edith's checkerspot butterfly and I know how to distinguish a good habitat from a bad one. And we know that this butterfly frequently goes extinct, and these extinctions are related to extreme climatic events."
She spent three years traveling through the distribution area of this butterfly, from Mexico to Canada, observing their habitats, and visiting all the museums where she could find records of these butterflies. What she discovered was that they were going extinct in Mexico, in low-altitude areas, and were thriving in Canada and at high altitudes.
Like Sherlock Holmes, she ruled out that the decline in the declining areas was due to habitat loss and degradation, the effects of agricultural fields, fertilizers, or pollution, demonstrating that the only factor that could cause the decrease of these butterflies was warming. This study was published in the journal Nature in 1996 and is considered the first concrete documentation of a wild species' response to climate change. Edith's checkerspot butterfly thus became a true thermometer of climate change.
In the following years, she was able to demonstrate that many other animal and plant species were experiencing the same impacts, after a laborious process during which she interviewed numerous butterfly collectors and traveled to museums in the USA and Europe. Spain was the second country where she demonstrated that many species were moving northward, a trend she documented in numerous countries.
Before settling in France in 2017, Parmesan had developed her career at the University of Texas and the British University of Plymouth. However, that year, she decided to join a program launched by the French President, Emmanuel Macron, to attract American scientists whose research would be affected or even canceled by the arrival of Donald Trump to power. If the US president popularized the slogan Make America Great Again, Macron named his program to attract American brains Make Our Planet Great Again.
The scientist admits that she never thought about moving to France: "I lived in Great Britain and planned to stay there, but then Brexit happened. I knew it would be catastrophic for research, and it has been. I considered returning to the US just when Trump was elected president for the first time. He didn't touch the universities, but in just a month, he had already informed thousands of climate scientists that they couldn't publish any article mentioning climate change, and they stopped funding climate studies. I knew many of the affected scientists in government agencies, and there was no way I could return to the US in that situation. Although I think I would have been fine at a university, the intellectual environment was really terrible for climate change back then," she recalls.
Not knowing what to do because there weren't many positions available for high-level scientists, she applied for a position in Canada, and that's when Macron made his proposal. She applied and got it: "People thought I was crazy because I gave up a permanent position in England for a five-year fellowship. But I told myself, 'I'll have fun for five years and I'll manage, and I'll find something else.' Besides, I was already retired, and I've always wanted to live in France," she says. She finally got a permanent position and has been directing the SETE station since 2022.
The scientist, now a sort of 'scientific refugee,' does not regret her decision to move to France and in fact, is very concerned about this second Trump administration: "During the first term, he made it very difficult for many climate scientists from government agencies, but he limited it to climate science and maintained funding for the US Global Change Research Program, the IPCC (the UN climate change expert group), or the World Health Organization. Now, he has expanded his attack to all of science, absolutely everything, from mathematics to physics, health, NASA... Everything," she warns. "In a few months, he has multiplied by a thousand the damage caused during his first term. There is no precedent for something like this. What he is doing is incredibly destructive, and we will not recover from this with a new president. It will take 20 or 30 years," she estimates.
Although Parmesan does not believe that Trump will succeed in having a third term, as he has expressed his desire, she fears that the current Vice President, J.D. Vance, could reach the White House: "It will be equally negative if he becomes president because he is the architect of much of what is happening."
From her point of view, if the proposed budget cuts by the Trump Administration to scientific institutions are implemented, they will not be able to function, so she believes that Congress should put a stop to it. On the other hand, she believes that states like California, the fifth-largest economy in the world, will be able to continue with many state programs, but others like Texas, Ohio, or Illinois will not be able to do so. Despite Texas being known as the oil state, the scientist assures that a lot of work has been done locally in the field of renewable energies: "In most of the major Texan cities, a good portion of the energy is renewable, particularly with wind farms. For example, in Georgetown, 100% of the energy is renewable, but Trump is cutting federal funding for research and new developments in renewable energies," she criticizes.
In addition to her studies on species, Camille Parmesan has been part of the IPCC for two decades and was one of the lead authors of the recent report issued in 2022 by this group of climate scientists. In the 90s, when she began her research, they thought the situation in 2025 would be different. "The planet's warming has been much faster than expected; we are already seeing temperature increases that were not expected until the end of the century," asserts the researcher, who is convinced that it is no longer possible to keep the global temperature increase below 1.5 degrees by 2100: "There is no way to achieve it, but I believe we could keep the increase below two degrees if we do everything possible to achieve it and expand nuclear energy."
In that sense, she advocates for the construction of new next-generation nuclear power plants: "They have designs that prevent their core from melting [they are called pebble bed reactors]. And now we know that we can make nuclear waste have a relatively short half-life of 1,000 years instead of 100,000 years because nothing can be safely stored when trying to do so for 100,000 years," she proposes.
Nuclear energy, she adds, will not be usable forever because we will run out of uranium: "It is not a solution but a bridge to a future where we will greatly improve battery storage capacity, given that the real problem with renewable energies is that we cannot store them as needed," she explains.
She also points out that the best batteries are based on metals and rare earth elements like lithium, which are also becoming very scarce, and their extraction is highly destructive. Therefore, she believes that "the ultimate answer will be energy generated by nuclear fusion," which is how the sun produces energy and is a developing technology "that could take 100 years to be available."
However, she emphasizes that combating climate change involves much more than burning fossil fuels: "It is about industrial agriculture that uses pesticides and fertilizers derived from oil, land use change, car pollution... We need to change many things," asserts this scientist, whose research has also focused on the effects that species loss and climate change have on both human health and food production. At the same time, she also works to determine which conservation measures are most effective in halting biodiversity decline.
Parmesan believes that we will inevitably lose some iconic species for humanity, but "we still have time to preserve global genetic diversity: "I don't think we can save what I call species adapted to the most extreme cold, like the polar bear, but their genetics will survive because they will crossbreed with other bears," argues the researcher, who advocates that conservation strategies should not focus on a specific species.
"The polar bear needs ice because it feeds on animals that depend on ice, such as seals, sea lions, walrus calves... When forced to be on land, it will eat whatever it finds because it is a bear: foxes, human garbage, or any other animal that does not contain the sufficient amount of fat it needs, which is very high. Gradually, its health deteriorates, as we are already seeing around Hudson Bay, where one of the southernmost populations is located. The number of cubs as well as the weight of the females has been decreasing because they are not eating what they need to eat," she explains.
Therefore, what polar bears are doing is mating with brown bears, resulting in hybrids: "Many conservation biologists and nature lovers are alarmed because we will not have any pure populations, but there are already polar bear populations that have a percentage of brown bear genes and vice versa. When the ice returns and the cold conditions, those polar bear genes will continue to exist in brown bears," argues the scientist. "Hopefully, if we maintain that genetic diversity in the global gene pool, when we stabilize the climate and start absorbing atmospheric CO2, all these animals will then have the opportunity to evolve again. That is my hope for many of these cold-adapted species. I am optimistic."