Rising sea levels can seem a little abstract until you see the effects on a map. These maps from National Geographic take the data to an extreme: This is what the world will look like if all of the ice on Earth melts.
With ice gone, water will submerge New York, along with most of the rest of the East Coast. Copenhagen and Shanghai will be gone, and the entire country of Bangladesh will disappear. In Australia, low-lying land in the outback would turn into a new sea, while the coastal cities where most Australians now live would go underwater.
Coastal cities almost everywhere, in fact, would be lost. And since most of the world’s large cities are on coasts, that’s a large chunk of human habitat as we know it today. Only some isolated parts of coastal land—like the highest hills in San Francisco, which would turn into tiny islands—would survive.
Since ice sheets and glaciers are massive, it would likely take quite a while before they’re entirely gone; some scientists predict the process could take thousands of years. But no one really knows exactly what to expect, and ice is melting faster than scientific models have predicted.
Every year, more than 350 billion metric tons of ice is melting in Antarctica and Greenland. A recent study now says that floating ice shelves in Antarctica that are several hundred meters thick, and over 10,000 years old, will likely be gone in only 200 years. As they go away, glaciers on land will also melt quickly.
Of course, the ice doesn’t have to disappear completely for melting to have huge impacts. Over a little more than a century, sea levels have risen only about eight inches, but that’s already impacting low-lying areas and being blamed for making damage from storms like Hurricane Sandy significantly worse.
By the end of this century, sea levels could rise three feet, or even as much as six feet or more. And while that's just a fraction of the 216-foot rise depicted in these maps, it's still enough to mean that places like Miami and the Maldives could soon be uninhabitable.