On the densely packed island of Gardi Sugdub, off the coast of mainland Panama, colorful houses and wooden huts cover nearly the entire landscape almost up to the water’s edge. Between them are unpaved roads, often wet and puddled, lined with just a few trees.

Gardi Sugdub is one of around 50 islands that are home to the Indigenous Guna people, who have built a life devoted to the ocean from fishing to tourism. But they were once people of the forests and mountains, living in an area that straddles Colombia and Panama, forced to flee around 300 years ago from Spanish conquerors and conflict with other Indigenous groups.

Now, the very ocean the Guna people have long relied on poses a threat to their existence, as rapidly warming global temperatures raise the world’s sea levels. The people of Gardi Sugdub are the first of Panama’s island communities asked by the government to move to the mainland in the coming decades.

After many years of planning, more than 1,000 Guna people have finally received keys to their new homes, and many have slowly started to move into a newly built town called Isber Yala in recent days. They are not legally bound to move, and plenty are choosing to stay on their home islands.

The people who live on the islands of the Guna Yala archipelago, which includes Gardi Sugdub, are among the first climate refugees in the region. Local residents on Gardi Sugdub, however, say there has also been long-standing concerns that their island is getting too crowded. The climate crisis has just expedited their relocation.

“The Guna people and other Indigenous communities in the Caribbean are going to be affected by the increase in sea level rise in the region, so of course we have to be prepared,” Blas Lopez, a Guna leader in Gardi Sugdub, who was part of the relocation committee, told CNN.

“It’s in the oral history of the Guna people, we always talk about what happens when the strong winds blow, the communities are flooded. The consequences can happen in 30 or 50 years. So, we have to organize, we have to plan.”

Even if the world dramatically cuts the planet-warming pollution that causes climate change, scientists say a certain amount of sea level rise has already been locked in until the end of the century. And that rise won’t happen uniformly around the world. Small, low-lying islands in the tropics, like those in the Guna Yala archipelago, will bear the brunt. Here, the rise is existential.

“Within 40 to 80 years — depending on the height of the islands and rates of sea level rise — most, if not all of the inhabited islands, will literally be underwater,” warned Steven Paton, director of the Smithsonian Institution’s physical monitoring program in Panama.