If climate change continues unchecked, the United States is on a path to large scale self-destruction. The consequences are myriad and all deadly: Drought, stronger storms, destruction of our crops, and rising sea levels: By the end of the century, sea levels would be on course to eventually rise anywhere from 14 to 32 feet. Now, a detailed new study maps out the terrifying scenarios of how this will reshape U.S. coastlines.

Anywhere from 20 million to 31 million people today live on land that will be endangered if nothing is done. These areas include portions of 1,200 to 1,800 municipalities and 21 larger cities. The the study, published in the Proceedings of the National Academy of Sciences, was also turned into an interactive tool by Climate Central. Click here to see exactly what land will be submerged in your city under a variety of different emissions scenarios and timelines:

With unchecked emissions through 2100, big cities like New Orleans and Miami would be among the hardest hit–though the maps don’t account for existing or future flood-prevention infrastructure, like New Orleans’ sea walls. Over time, both cities would be totally flooded, though the authors don’t estimate how long the timeline would be. It could take 200 years, it could take much more. Even taking action to limit global warming to 1.5 to 2 degrees Celsius–which is the goal of international climate negotiations taking place in Paris this year–is not enough to save these cities. The maps still show that, even if we stall climate change, by 2100 most of these two cities will be set for an underwater fate.

There is hope though for many other, better positioned cities. If there are aggressive carbon cuts that limit warming to 1.1 degrees Celsius and peak greenhouse gas emissions in 2020, many could avoid these impacts. One big uncertainty is the fate of the West Antarctic Ice Sheet–if it remains stable, more than half the area under threat would be spared. However, recently scientists have become concerned that the ice sheet is already doomed to collapse. In that case, the outlook is gloomier.

What is clear is that nations needs to make bigger emissions cuts than what’s currently on the table to avoid the worst. As the study notes: “Although past anthropogenic emissions already have caused sea-level commitment that will force coastal cities to adapt, future emissions will determine which areas we can continue to occupy or may have to abandon.”