For some reason, BuzzFeed on Monday seized on a National Geographic interactive from last month showing what the continents would look like if the oceans rose 216 feet. That figure, credited to the U. S. Geological Survey, doesn't appear online. And, in fact — it's probably too low.
Here's how the magazine describes the rationale for its analysis of what a drowning world will look like.
According to the U.S. Geological Survey, sea level on an iceless Earth would be as much as 216 feet higher than it is today. It might take thousands of years and more than a thousand parts per million to create such a world—but if we burn all the fossil fuels, we will get there.
That "thousands of years" caveat is an important one; the maps suggest what the world would look like if all of the glaciers and ice caps on Earth melted under warmer temperatures. That's not going to happen in your lifetime. It may not happen in the United States' lifetime.
The problem is that we can't find that "216 feet" figure anywhere — and the only numbers from the USGS say the sea level rise will be higher. In 2004, USA Today used a figure of 215 feet, crediting the USGS, but that isn't anywhere to be found, either.
The agency's sea level rise information page puts the number at 80 meters — some 262 feet. It's broken down by melt location.
- If all of Alaska's glaciers melted, sea level would rise ~ 0.05 meters (about 0.16 feet).
- If all of Earth's temperate glaciers melted, sea level would rise ~ 0.3 meters (about one foot).
- If all of Greenland's glaciers melted, sea level would rise ~ 6 meters (about 19.7 feet).
- If all of Antarctica's glaciers melted, sea level would rise ~ 73 meters (about 240 feet).
That appears to be based on this 2000 study, which puts the exact figure at 80.32. One USGS report (that isn't dated) puts the figure higher still: "If all the present glacial ice were to melt from Antarctica and Greenland, the oceans would rise another 300 feet (90 meters) and inundate most of the coastal cities of the world."