Maybe you've encountered them in the Wild Area in Pokemon Shield or received one through a trade in Sword, but you may have missed the seemingly tragic origins of both Galarian Corsola and Cursola, its evolved form. A Pokedex entry says that "sudden climate change" led to the extinction of these coral Pokemon, leaving these Ghost-type forms in their wake.
As Earther points out, it's a reference to the very real problem of coral bleaching, but Sword and Shield actually stop short of directly linking Corsola's bleaching with anthropogenic (human-caused) climate change. While the new form of Corsola serves as a bleak reminder of our real-life climate woes, it seems like it's not as urgent of an issue in the Pokemon world.
To see this, we need to take a closer look at the Pokedex. Serebii helpfully lists the entries from Sword and Shield for both forms of Corsola: the Galarian Ghost-type and the original Water and Rock-type, introduced in Gen 2. Shield's entry for Galarian Corsola says "sudden climate change wiped out this ancient kind of Corsola." The entry for the original variant of Corsola, meanwhile, notes that "in prehistoric times, many lived in the oceans around the Galar region as well." Even though Galarian Corsola and Cursola evoke the present-day coral bleaching that experts say is being accelerated by human impacts on the climate, in the fiction of Pokemon they actually arose from a pre-industrial period of climate change.
In the past, Pokemon has included other nods to how humanity endangers coral reefs. Pollution is also a significant real-life threat to coral reefs, and previous Pokedex entries for Corsola have said that they like to live in "unpolluted southern seas." Corsola's entry from Black and White 2 even makes reference to coral bleaching: "their coral branches lose their color and deteriorate in dirty water."
In that sense, Corsola and Cursola aren't out of line with other references Pokemon has made to humanity's impact on the environment. Remember, there are Pokemon that thrive off of pollution or originate from it, and it seems that not all of them harm the environment. Take Galarian Weezing, for example: Shield's Pokedex entry says Weezing took on its smokestack appearance "during a time when factories fouled the air with pollution," while Sword's reveals that Weezing "consumes particles that contaminate the air" and then "expels clean air." Weezing's a floating toxin factory... and also an air purifier.
Another classic pollution-loving Pokemon is apparently threatened by the world being too clean. Moon's entry for Muk notes that "after recent environmental improvements," Muk is at risk for extinction, while Ultra Sun references "sludge ponds" being made to preserve them.
So, while it's still noteworthy that Pokemon explicitly used the term "climate change" this time around, the games don't point the finger at humanity. More and more real life reefs may resemble Galarian Corsola and Cursola, but the present day Pokemon world is dealing with a problem where there's not enough trash to go around. As far as species-threatening problems go, that one seems a lot easier to solve than climate change.
If you're looking for more on Pokemon Sword and Shield, head on over to our Pokemon Sword and Shield Everything We Know Page. If you'd like to know which of your favorite Pokemon have made the cut for Pokemon Sword and Shield, head to our Pokemon Sword and Shield New Pokemon Guide. Finally, why not take a look at all of the differences between Sword and Shield we know about so far in our Pokemon Sword and Shield Version Exclusives Guide.