Study Identifies Areas Most Likely to Sustain Biodiversity in a Changing Climate
Royal Tern. Photo: Bill Dix/Audubon Photography Awards
NEW YORK (January 11, 2023) – As the world contends with a dual biodiversity and climate crises, a new assessment of land-based biodiversity in North America has identified areas considered to be climate refugia—areas likely to provide viable habitat for their current species—under several warming scenarios. The study's findings show that areas most critical for sustaining species lack current protections or conservation management.
The study was authored by the National Audubon Society, the Tyndall Centre for Climate Change Research at the University of East Anglia, and Michigan State University in partnership with James Cook University and the Wallace Initiative. It was published today in Frontiers in Ecology and the Environment. The research comes after the U.S. adopted several historic measures responding to climate change, including the Inflation Reduction Act, the Bipartisan Infrastructure Law, and the America the Beautiful initiative to protect 30 percent of lands and waters by 2030, also known as the 30x30 initiative. A similar 30x30 pledge was made on an international scale at the recent UN Convention on Biodiversity.
“As average global temperatures continue to rise, we must conserve those natural areas that are most likely to help species withstand a warming planet,” said Sarah Saunders, senior manager of quantitative science at the National Audubon Society and the study’s lead author. “It’s laudable that governments are adopting measures like the America the Beautiful initiative and have pledged to preserve 30 percent of global lands and waters by 2030. These climate refugia should be included among the areas conserved by these ambitious plans.”
The study shows how the availability of climate refugia for terrestrial biodiversity across North America changes under 1.5, 2, 3, and 4 degrees Celsius of warming. Those 20-km areas that were able to maintain at least 75% of their current species under each warming scenario were considered refugia. The study looked at how refugia for birds, amphibians, fungi, invertebrates, mammals, plants, and reptiles were affected.
The study also finds that the higher global temperatures rise, there will be fewer opportunities to protect climate refugia. The study findings make clear that it is imperative to hold global temperature rise to no more than 2 degrees Celsius. For example, at 2 degrees of warming in the United States, 51 percent of identified high-priority refugia will still exist. That number falls to 39 percent at 3 degrees of warming, at which point refugia will be limited to higher elevations and latitudes. The change will happen too quickly for most wildlife to adapt, further worsening the biodiversity crisis.
The consequences for biodiversity will have a bottom-up effect. Refugia for plants and fungi will be the most reduced by extreme warming, which can then have consequences for herbivores’ ability to adapt, which in turn can affect species higher on the food chain.
As the climate warms, many species have seen dramatic changes in population. For example, studies have shown that there are 3 billion fewer birds than there were in 1970. A 2019 Audubon study found that two-thirds of North American bird species will be vulnerable to extinction if temperatures rise above 1.5 degrees Celsius.
However, of those areas identified in the study as refugia in North America, less than 15 percent are currently managed for biodiversity conservation. In the U.S., that figure is even less: 2-6 percent depending on the warming scenario, which is behind both Canada (4-10 percent) and Mexico (5-14 percent).
“Addressing the alignment of protected areas and refugia will require international coordination, as availability of refugia may differ across borders,” said Mariah Meek, assistant professor of integrative biology at Michigan State University. “While climate refugia may be plentiful in the U.S. today, that may not be true tomorrow given ongoing climate change.”
“Every effort must be made to adapt to and alleviate the effects of climate change,” said Sarah Rose, vice president of climate at the National Audubon Society. “In addition to critical measures to reduce emissions such as investing in renewable energy, and conserving and increasing landscapes and agricultural lands that naturally capture carbon, we must also maintain places where climatic conditions are relatively stable to give wildlife and habitats a chance to adapt.”
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The National Audubon Society protects birds and the places they need, today and tomorrow. Audubon works throughout the Americas using science, advocacy, education, and on-the-ground conservation. State programs, nature centers, chapters, and partners give Audubon an unparalleled wingspan that reaches millions of people each year to inform, inspire, and unite diverse communities in conservation action. A nonprofit conservation organization since 1905, Audubon believes in a world in which people and wildlife thrive. Learn more at www.audubon.org and on Facebook, Twitter and Instagram @audubonsociety.