There are 3,800 big thermometers (free-drifting profiling floats) that measure the temperature and salinity of the upper 2000 m of the ocean, and the readings don’t lie: Over 90 percent of the warming created by humans is soaked up by the seas. And its no surprise, many creatures are feeling the heat.
In new research published in the journal Nature, scientists found that global warming has forced twice as many marine species than land species to vanish from their hotter habitats. This behavior is particularly happening near the already balmy equator. All the species examined were cold-blooded, or ectotherms.
“What we found so surprising is that global warming hits sea creatures the hardest,” said Malin Pinsky, an evolutionary ecologist at Rutgers University and lead author of the research.
It’s surprising because it gets so much hotter on land and sea critters aren’t adapted to deal with such significant temperature increases. That’s the problem!
As temperatures warm, especially in the already hot tropics, creatures can’t tolerate the heat and leave. What Pinksy and his team found were local extinctions. Extinctions meaning over half of the 108 sea creatures they studied left their native homes and moved to cooler waters. Meanwhile on land, about a quarter of species — like species of lizards and geckos — left their homes as things heated up.
Many of these marine species that are being forced to flee from warming waters are not just well-known, they’re often food for humans, like halibut and winter flounder. “This affects our dinner plates in many cases,” said Pinksy.
After diving into more research on the known temperature limits of marine and animal species, Pinsky and his team also found that sea creatures are more likely to live on the edge of “dangerously high temperatures.” Sadly, in many cases, they don’t have a choice.
As the planet’s warming becomes more apparent (18 of the last 19 years have been the warmest on record), perhaps the conditions of sea creatures will receive more attention. “Ten years ago there was almost no discussion of the [climate] impacts on marine animals,” said Pinksy. “Now we’re finding they’re the most sensitive.”
Sea creatures can’t simply swim to deeper, colder climes. Deep-sea critters have spent millions of years adapting to the deep, dark, isolated ocean. Fish near the surface can’t just go down and expect to make a living, especially in the food and energy-starved depths.