Via Gizmodo: ‘At a UNESCO climate conference last week, scientists declared (once again) that climate change is already happening. The evidence is our wacky weather—even Paris, where the conference was held, was broiling in a historic heatwave. But the biggest red flag is the rise in peak global mean temperatures: Which means rising sea levels will almost certainly be a reality, too.

As a lead up to the bigger UN climate conference this fall, scientists are now modeling two different warming scenarios to help humans plot a roadmap for how to avoid these futures. Status quo—or even going back to “preindustrial levels”—is no longer an option, even if we ceased all carbon-emitting activity right now. One scenario is if the planet will warm by 2 degrees Celsius by the end of the century, which would be very bad. The other is if the planet will warm by 4 degrees Celsius, which would be very, very bad.

In this month’s Science, a study looked at these warming trends and made some estimates for how these temperature increases would help to accelerate the melting of polar ice sheets. Two or three degrees Celsius would see a rise in sea levels of at least six meters. That’s about 20 feet.

So say we manage to only raise temperatures by 2 degrees Celsius—the best-case scenario. A map made by Climate Central allows you to visit any city to see exactly how much coastlines will change. While there are plenty of usual suspects in this list—Miami would be totally underwater, of course, and we got previews of how rising ocean levels would affect New York City and New Orleans during Hurricanes Sandy and Katrina—there are also some areas that will see a surprising loss of land….’

Of course, I went right to my home city, Boston. The results were quite scary… and that’s only 2 degrees.