A new study showing how climate change threatens the migration patterns crucial to many birds’ survival is a reminder of how sensitive wildlife is to even the slightest uptick in temperatures.
In a study of 413 species across five continents, researchers with the University of Edinburgh found that, on average, migratory birds are arriving at their summer breeding grounds about one day earlier for each degree Celsius that global temperatures rise.
That may not sound like much, but the consequences can be severe.
The study, published Wednesday in the Journal of Animal Ecology, is not the first to note the ties between climate change and avian migration. But it’s the most extensive analysis of its kind, its authors say, and pulls from observations made as far back as 265 years ago, including those of 19th-century naturalist Henry David Thoreau.
While rising temperatures were found to prompt early migration in birds across the board, the study found that short-distance migrants are arriving at their destinations significantly earlier than long-distance migrants.
Those changes throw off a delicate balance in the ecosystem and could have serious effects. If migratory birds arrive at their breeding grounds too early or too late, relative to those arriving even earlier there’s a potential for “mismatch of trophic interactions,” the study explains, meaning the birds may miss out on peak resource availability or face stronger competition for breeding sites or mates. This would affect the timing of their offspring hatching, putting the baby birds’ survival at risk, too.
Of course, none of this would occur in a vacuum. The endangerment or extinction of one species can have reverberations up and down the food chain, creating a dangerous ripple effect across entire ecosystems.
The study comes just days before the end of what will likely prove the hottest year on record thus far. While NASA and the National Oceanic and Atmospheric Administration are expected to release their findings next month, Dr. Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, tweeted in October that the record was probably already “locked in.”
President-elect Donald Trump has raised much alarm over wind turbines, a renewable energy tool that could prove crucial to the ongoing effort to reduce carbon dioxide emissions. Trump has argued that turbines kill birds that collide with them.
This may be true: Studies estimate that every year, turbines are responsible for somewhere between 140,000 and 368,000 bird deaths worldwide. But these numbers pale in comparison to the potential consequences of climate change. The Audubon Society has found that climate change threatens more than half of all bird species in North America alone.