Climate change will displace habitats prioritised for marine protected areas in the high seas

Imagine the ocean as a giant, living library. For centuries, humans have tried to protect the rare and precious books inside by locking them in specific, unchanging rooms called Marine Protected Areas (MPAs). These rooms are like "no-fishing" zones where nature is supposed to thrive without human interference. But there's a catch: the ocean isn't a static building; it's a flowing, shifting river of water. As the planet warms, the "climate" inside these rooms is changing. The water gets hotter, saltier, or greener in different ways, forcing the sea creatures that call these rooms home to pack up and move to find their perfect conditions elsewhere. This study looks at what happens when the library's rooms stay locked in place, but the books (the habitats) start walking out the door.

The scientists behind this research focused on the "High Seas," the vast stretches of ocean that belong to no single country. They looked at special zones called EBSAs (Ecologically or Biologically Significant Areas), which are like the library's most important, rare books that the world has agreed to protect. The big question was: If the climate keeps changing, will these protected zones still contain the right environment for the creatures they were meant to save by the year 2100?

The researchers ran a massive computer simulation, acting like a time machine, to see how these ocean zones would change under three different future scenarios: one where we cut carbon emissions drastically (low), one where we cut them a bit (medium), and one where we keep burning fossil fuels like there's no tomorrow (high). They tracked the "habitat velocity"—how fast and how far the perfect ocean conditions would have to move to stay the same.

The results are a bit like watching a game of musical chairs where the music never stops. The study found that by 2100, the distance the ocean's perfect conditions need to travel could nearly triple, depending on how much we pollute. Under a low-emission future, about 94% of these protected zones would still keep at least half of their original "perfect" habitat. But if we keep emissions high, that number drops to just 57%. In the worst-case scenarios, the Arctic zones are in big trouble; the paper suggests that none of the Arctic EBSAs will be able to keep their original conditions, no matter what we do.

The most surprising discovery is that static fences don't work well in a moving ocean. The study suggests that only about one-third of these high-seas zones are "climate-proof" enough to stay put and still protect the life they were designed for. For the rest, the environment they were built to protect is literally walking away. However, there is a hopeful twist: the paper suggests that if we could make these protected areas "dynamic"—meaning they could stretch, shrink, or move along with the shifting ocean conditions—we could still protect the original habitat. It's like if the library could magically slide its walls to follow the books as they move.

The authors emphasize that while shrinking our carbon footprint is the best way to slow this down, it won't stop the movement entirely because the ocean reacts slowly. So, the future of ocean protection likely needs a mix of two things: cutting emissions to slow the shift, and creating flexible, moving protected areas that can chase the changing climate. Without this double approach, many of our current "safe zones" might end up protecting an empty room while the life they were meant to save has moved on to a new neighborhood.