As if there weren't already enough downsides to climate change, warming water temperatures allow venomous sea animals to spread to new locations.
A study published in Wilderness and Environment Medicine found that global warming is making the equator too hot for many venomous predators, so they're moving farther north and south as those waters warm as well.
For example, jellyfish love warmer waters and reproduce more in those conditions.
They're creating blooms of jellyfish.
Popular Science reports that while some ocean life, like coral, can't survive rising water temperatures and acidity levels, jellyfish thrive. According to Popular Science, in Australia, reports show that the extremely poisonous box jellyfish is showing up for much more of the year than it used to and moving farther south as well.
In addition to jellyfish, other venomous creatures like lionfish, sea snakes and crown-of-thorns starfish are stretching in range. Lionfish, usually known for invading the warmer waters of Florida, have been seen all the way in New York, according to Popular Science.
Another NatGeo article reported that yellow-bellied sea snakes have been showing up in California in recent years. Four have been spotted since 2015. Prior to that, only one snake had ventured that far north, and it was in 1972.
And while four snakes may not sound like a lot, it's simply a sign of what's to come as water temperatures rise.
This is all bad news for humans and the ocean alike.
According to NatGeo, the authors of the venomous animals study are worried that hospitals may not be prepared to treat the stings of these poisonous creatures as they move to new territory. Plus, these new species are often invasive to their new homes, wreaking havoc on areas already threatened by climate change in other ways.
The National Ocean Service reports that lionfish, for example, have no known predators, but they compete with indigenous fish for food and space. They can threaten the balance of an entire reef, and seeing them move northward is bad news for those ecosystems.
Meanwhile the crown-of-thorns starfish eats coral, according to the Great Barrier Reef Marine Park Authority, and they can destroy whole reefs of already vulnerable coral, per NatGeo.
While people are still working on ways to combat climate change and stop or reverse its dangerous effects, that may take a long time. So, in the meantime, keep an eye out when you're in the water.