[ ♫ INTRO ] The climate disaster is  affecting every place on Earth, but it’s not affecting everywhere in  the same way, or to the same extent.

Among the most vulnerable places are  those susceptible to the rising seas. That might bring to mind great  cities like Miami or Venice, but it’s also true of tiny  communities like Tangier Island, in America’s Chesapeake Bay.

And the cost to save even small villages like the one on Tangier Island  should raise alarm bells   about the overall impact of this climate disaster, according to a paper published this week  in the journal Frontiers in Climate. In it, two researchers estimated it could cost more than a quarter of a billion  US dollars to save just a few hundred homes. And policymakers will have to  decide soon about what to do, because in just 30 years, the  island will not be habitable at all.

Today, Tangier is home to around  four hundred permanent residents, and it’s said to be the only remaining  island fishing community in Virginia. The island’s remaining habitable land has an  elevation less than one meter above the high tide. That solid ground is broken into three chunks, which the paper somewhat  optimistically calls “ridges.” Between the ridges are even lower-lying wetlands, crisscrossed by the roads that connect the ridges.

This precarious situation is made worse  by the fact that the Chesapeake Bay is experiencing sea-level  rise at an unusually high rate around one centimeter every two years. Using historical satellite images, the  researchers determined that since 1967, the island has lost 62% of its habitable area. Saltwater is so close to the  surface that trees cannot survive.

Two of the island’s three remaining ridges will likely become wetlands by 2035, while the last hangs on for another fifteen years. The study investigates two possible  responses to this situation:   raising the island or evacuating its population. Saving the island would  require several key actions.

First is reinforcing the existing  shoreline to stop further erosion. Next, covering the remaining habitable  land with sand to raise it by several meters. Of course, since this area is  covered in existing buildings, those buildings would have to be raised up and then placed on the new ground.

Finally, the town’s infrastructure,  such as roads, plumbing, and power lines will need to be relocated to  ensure that they stay above the rising water table. In total, the authors estimate that these actions  could cost between 250 and 350 million dollars. That is a lot of money, and a cost that  could not be borne by the community alone.

Those other option, of course, is to basically  give up on Tangier Island and help the remaining residents  relocate to a new area. But that wouldn’t be cheap, either. Based on the real-world costs already  paid to relocate similar communities, the researchers estimate that the government  would need to spend 100 to 200 million dollars.

That’s up to half a million dollars per citizen. And, unfortunately, Tangier Island is not alone. A 2019 study estimated that, worldwide, 230 million people live on land that is less than a meter above sea level.

Each community and geography comes with  its own unique challenges, so we can’t just scale up  the estimates from Tangier. But they’re probably not that  big of an outlier, either. And many at-risk communities are low-income, indigenous, minority, or generally  unable to bear the costs.

There’s no easy answer here,  but it’s a reminder that, when it comes to fighting the climate crisis,  doing nothing comes with costs of its own. So how about we turn to some more warm-fuzzy news. A paper published October 28th in the  journal Scientific Reports helps corroborate the idea that one of the Ice  Age’s most fearsome predators was capable of looking out for others of its kind.

The study focuses on Smilodon, better  known as the saber-toothed cat. Smilodon was an apex predator  during the Pleistocene, which spanned 2.6 million  years ago to just 10,000 BCE. ~ Understanding social behavior in extinct  animals has long been a challenge, especially for species without living relatives. After all, our social inclinations  depend on more than just our bones.

But, in this case,  the state of the animal’s bones was a pretty big tip-off. The specimen in question is a Smilodon pelvis retrieved from California’s La Brea  Tar Pits almost a hundred years ago. The right hip socket on this  particular bone is badly damaged,   which paleontologists have long  assumed was the cause of its death.

But this new study suggests otherwise. The researchers took the bone  and placed it in a CT scanner. And that revealed evidence that this creature  was suffering from hip dysplasia, a condition common in modern day cats and dogs.

In hip dysplasia, the hip’s  socket doesn’t fully form, allowing the ball of the thigh  bone to slip out and dislocate. The key here is that dysplasia is  something an animal is born with. It would have made it almost impossible  for this creature to hunt for itself, yet the size of its bones and the way they’re  fused indicate this animal reached adulthood.

And the researchers say that is the  clue that points to social behavior. Other saber-tooths would have had to  protect it, feed it, and stay with it exactly the sorts of behavior  found in social animals. What’s more, this doesn’t seem  to have been a one-off situation: at least three other pelvises found at La  Brea show possible evidence of dysplasia.

Other evidence has suggested that Smilodon  young may have been cared for by their mothers for an unusually long time, which  could also help explain these results. In any case, it’s another example of  the unique approach paleontologists have to take when exploring life’s ancient past. And it’s neat to discover our  surprising similarities with creatures that could not seem more different.

Thanks for watching this episode of SciShow. Making these videos would not be possible  without the generous support of our patrons. You can get involved, plus score some neat  peeks behind the scenes, at patreon.com/scishow. [ ♫ OUTRO ]