On the eighth of a nine-night funerary celebration, a circle of about 20 people sat in solidarity to celebrate Pan-Africanism and honor their ancestors. It was unusually warm for a late October evening in Brooklyn. The 72 degrees Fahrenheit weather might be convenient for an outdoor ceremony, but on this night in the Flatbush African Burial Ground, it served as a reminder of a brewing battle.

The rugged earth beneath—which houses the remains of enslaved Africans who lived and died two centuries ago—was spongy and moist from extreme flooding that had unexpectedly hit New York City three weeks earlier, shutting down subway lines and leaving some neighborhoods like this one underwater. As Panamanian musicians sang in their mother tongue, dancing attendees took care to avoid the ground’s uneven dips and muddy puddles.

The theme of the night’s ceremony was the African diaspora, and as a microphone passed around the circle, attendees shared their ancestral history: Moroccan, Nigerian, South African, Irish, Ghanaian, Native American, Trinidadian. A musician shared his experiences with racial discrimination and feeling isolated from his African roots. As another speaker discussed being a descendant of slaves, and how so many ancestors drowned before reaching America, attendees swatted away mosquitoes nesting near the still flood water.

This burial ground is a sacred place for people to collectively honor African ancestors who were subjected to slavery. But now it faces a new threat: climate change.