The ability to see first-hand the effects of climate change on vulnerable ecosystems underpins the work of these three scientists, whose research has taken them to glaciers in Greenland, fishing communities in Mexico and the landing sites of migratory shorebirds all over the world. But it’s not just about the fieldwork. For these scientists, a commitment to outreach and behaviour change is just as important in the fight to stave off the worst impacts of a warming planet.

CHI-YEUNG CHOI: Bird’s-eye view

Chi-Yeung (Jimmy) Choi has loved birds since he was a child growing up in Hong Kong. When he moved to Sydney, Australia to complete an undergraduate degree in biological ecology, his friends introduced him to birdwatching — an experience that opened up a whole new world of exploration, and set his future career path.

Waterbirds captured Choi’s interest. “They’re very easy to see, if you go to the right place at the right time. And they do remarkable things,” he says, referring to the tens of thousands of kilometres that many migrating waterbird species travel each season.

“It’s inspiring,” says Choi, whose research focuses on waterbird ecology. Similar to his subjects, Choi has travelled to various parts of the world, conducting fieldwork in New Zealand, Taiwan, Australia and Antarctica.

Nature Index 2023 Climate and conservation

Now an applied ecologist at Duke Kunshan University in Kunshan, China, Choi’s work covers three main areas: examining how aspects of climate change, such as shifts in wind patterns, affect migration journeys; identifying ways to conserve migratory bird populations; and understanding the factors that drive different waterbird populations to use the East Asian-Australasian Flyway, a broad corridor that extends from Arctic Russia in the north, through China, to Australia and New Zealand in the south.

Migratory waterbird survival has been affected by rising global temperatures, says Choi. He points to the red knot (Calidris canutus), a species of Arctic-breeding sandpiper. Chicks are reportedly getting smaller because their hatch dates are out of sync with peak periods of insect activity, which now occurs earlier in the year because of premature snowmelt¹.

Governments worldwide have begun to pay attention. China, in particular, has made “rapid progress” with its climate and conservation-related policies in the past five to ten years, says Choi. For instance, in 2017, China began implementing the Ecological Conservation Redline strategy, aimed at preserving areas that are highly fragile or have crucial ecological functions by expanding the number of protected sites, improving their management, and restricting or banning development from taking place. When Choi and his collaborators assessed the strategy, they found that it could potentially triple the number of key coastal waterbird sites under protection in the country². The policy change has resulted in fewer natural wetlands being converted into aquaculture ponds for fish farming, farmlands and other developments. “It’s really encouraging to see such a change,” says Choi.

Although the speed at which these actions are being carried out is impressive, it does make it challenging for researchers to keep up, says Choi, especially when they’re not brought in on the planning stages.

“Sometimes, things change a little too rapidly,” he says. “Because these policies have been implemented on such a big scale and at such rapid rates, there is often very little time for us researchers to really evaluate the impacts.”

For example, when the authorities decided to plant trees in a mangrove forest in China’s south, in an effort to create a carbon sink, they failed to consult experts, who would have advised them that their well-intended actions could have a negative impact on the area’s critically endangered migratory waterbirds, which prefer bare tidal flats to those crowded with trees, says Choi. “The question is not about how quickly the transition can be made, but about how sustainable and scientifically sound those policies are,” he says.

For their part, Choi says scientists can play a role in the fight against climate change by ensuring their research isn’t too abstract. “We make a lot of fantastic models and give recommendations, but if we don’t take into consideration what’s important for local people’s livelihoods and for decision-makers, then our research won’t be applicable.”

Choi hopes his work will help to bring the most threatened waterbird species back from the brink. “I hope endangered populations can recover so that our children and grandchildren can continue to appreciate the remarkable journey that is being conducted by these species,” he says. — Sandy Ong

MARINA BANUET-MARTÍNEZ: Climate–health connection

Growing up in the landlocked state of Querétaro in central Mexico, a nine-hour drive from the coast, Marina Banuet-Martínez was intrigued by the ocean from an early age. She recalls her teacher asking the class to illustrate what they wanted to be when they grew up. “I drew a picture of the ocean, because I wanted to be a marine biologist,” she says.

Years later, as an undergraduate student at the Autonomous University of Querétaro in Santiago de Querétaro, Banuet-Martínez stood on the shore along Mexico’s north Pacific Coast and had a full-circle moment. “The first time I got there, I was like: ‘Oh man, I drew this.’”

She would go on to study the impact of climate anomalies on the health of California sea lions (Zalophus californianus)³ and other marine species for the next seven years, before switching her focus to people. “The impact on the sea lions’ physiology was huge, and I wondered if it was the same for the people who share the same space and resources with them,” she says.

Now a PhD student in epidemiology at the University of Alberta in Edmonton, Canada, Banuet-Martínez leads the Fishers, Nutrition, Health, & Climate Change project to examine how climate change affects marine ecosystems in Baja California, Mexico. With partners from Comunidad y Biodiversidad, a non-profit organization in Guaymas, Banuet-Martínez has been conducting surveys and interviewing fishers and their families to understand how changes in daily catch have affected their diets and livelihoods. “Their knowledge about environmental change is amazing — they can give you really valuable information about what is happening to the species they depend on,” says Banuet-Martínez.

Although fishers worry about how a decline in marine species could affect their income, they don’t necessarily consider the consequences that this might have on their physical and mental health, says Banuet-Martínez. Having completed the data-collection phase of the project, she will spend the remainder of her PhD translating the information into models that will help to estimate these health effects.

In 2022, Banuet-Martínez received the prestigious International Doctoral Research Award from Canada’s International Development Research Centre in Ottawa, a prize that supports research to improve lives in the global south. She says that being able to conduct fieldwork in her home country has been invaluable: “I think it’s a great opportunity for me, as a Mexican, to bring resources and knowledge and my scholarship there.”

Climate-related research can have “a stressful and gloomy component”, Banuet-Martínez admits, but she’s spurred on by the fact that “there is a lot of work to do”. To speed things along, it would help if policymakers embraced a ‘short-term pain, long-term gain’ mindset when thinking about investing in climate solutions, she says. But she notes that researchers also have a part to play. “If you have the skills and knowledge, it’s in your hands to do it,” says Banuet-Martínez. “I feel like I do, and that I’m in the perfect place and time to do some research, and to see if my contributions can positively influence future ecosystems.” — Sandy Ong

ROMAIN MILLAN: The glaciologist

When Romain Millan started his PhD at the University of California, Irvine, to investigate the behaviour of glaciers, he assumed he’d be relying on existing data to support his research. “When my supervisor told me that I was going on two expeditions to Greenland in the same summer, I couldn’t believe it,” he recalls.

It was a dream come true for Millan, now a glaciologist at the Institute of Environmental Geosciences in Grenoble, France, but he soon realized the challenges of remote fieldwork. “The eight-hour boat ride to the data-collection site was so bumpy, I was seasick during the entire trip,” he says. “When we arrived, we were looking up at the glacier face for the first time. Although I was super-exhausted, at that moment, I saw how vast the glacier was and I was captivated by its beauty. It’s really the kind of moment that motivates my work.”

Millan specializes in the use of satellite and airborne-sensor data to monitor glaciers. In 2022, he and his colleagues published a comprehensive, high-resolution map of the flow and volume of more than 200,000 mountain glaciers⁴ — 98% of the world’s total. The team used data captured by satellites equipped with optical and radar sensors and converted them into flow and volume results using computational models. More than 800,000 pairs of glacier images recorded up to 400 days apart in 2017–18 were included in the study.

A key part of the research has been calculating how much water is held by the world’s glaciers. Because the flow of a glacier is influenced by its mass, Millan and his colleagues were able to update water-volume estimates for several glaciers, including those in the Upper Indus and Chenab basin of the Himalayas, and the tropical Andes of South America. “We found that there is 34% more ice in the Himalayas and 27% less ice in the tropical Andes than previously estimated,” says Millan, who is among the most prolific early-career authors in the Nature Index on climate and conservation topics. “This has had a significant impact on water availability for local populations in the Andes and may necessitate a revision of policy on water distribution among the affected people.”

It is crucial for researchers in climate-change-related fields to be mindful of how they communicate their findings to the public, says Millan, who participates in outreach programmes in high schools across France. The typical ‘top-down’ approach of communicating scientific findings, in which the scientist speaks and the public listens, can be counterproductive, he says. “We need more open and constructive debate at all levels of society.”

It is also important for researchers to make their own personal efforts in reducing carbon emissions if they want to see wider change, says Millan. At his institution, he is joining a group of scientists who are committing to reducing their emissions by 50% by 2030 through measures such as using trains instead of planes whenever possible, renting electric bikes and making changes to improve the energy efficiency of their buildings. “If climate scientists want to convince society that everyone must do their part to fight climate change, we have to be the first to change our behaviours,” he says. — Andy Tay