For millennia, some of the world's largest filter-feeding whales, including humpback whales, fin whales and blue whales, have undertaken some of the longest migrations on Earth each year to travel between their warm breeding grounds in the tropics to nutrient-rich feeding destinations in the poles.
“Nature has finely tuned these journeys, guided by memories and cues from the environment that tell whales when to move and where to go,” said Trisha Atwood, an ecologist and associate professor at Utah State University's Quinney College of Agriculture and Natural Resources. But, she said, climate change is “confusing these signals,” forcing the marine mammals to veer off course. And they are not the only ones.
Earlier this year, Atwood joined more than seventy other scientists to discuss the global impacts of climate change on migratory species in a workshop organized by the United Nations Convention on the Conservation of Migratory Species of Wild Animals. The organization monitors and protects more than 1,000 species that cross borders in search of food, mates and favorable conditions to feed their offspring.
More than 20 percent of these species are on the brink of extinction. It was the first time the convention had met for such a purpose, and their findings, published in a report this month, were alarming.
“Almost no migratory bird remains unaffected by climate change,” Atwood said in an email to Inside Climate News.
From whales and dolphins to Arctic shorebirds and elephants, all are being affected by rising temperatures, extreme weather and changing ecosystems, disrupting migration routes and reshaping critical habitats across the planet.
Asian elephants, for example, are being driven to higher ground and closer to human settlements as they search for food and water amid worsening droughts, causing increasingly frequent human-elephant conflicts, the report found. Shorebirds reach their Arctic breeding grounds out of sync with the insect blooms their chicks depend on for survival.
The seagrass beds where migrating sea turtles and dugongs feed are disappearing due to warmer waters, cyclones and sea level rise, according to the report. To date, about 30 percent of the world's known seagrass beds have been lost, threatening not only the animals that depend on them, but also humans. These vital ecosystems store about 20 percent of the world's ocean carbon, in addition to supporting fisheries and protecting coastlines.
