Dec 102014
U.S. cities under water

According to a PBS article, Will Your City be Under Water, previous estimates of just how many U.S. cities would flood were too conservative because scientists only considered the relation of the land to sea level but not to high tide. For example, about 5 million people live in about a quarter of a million residences that are less than four feet over high tide. That’s within a century, but sea levels could rise by 19 inches by 2050, and that’s well within many of our reader’s lifetime.

The Surging Seas Interactive Map

This widget comes from, and it allows you to adjust for different predicted levels of rising waters and high tides to see current predictions. You can choose to view maps, see quick summaries, and spend time viewing a very detailed analysis. In some cases, this drills down to the neighborhood level or threatened cities.

If you’re interested in seeing if your own city is threatened by rising tides, you can also visit for an interactive map and much more detailed analysis. The estimates of rising sea levels and tides in the next century is from two to seven feet. The map allows you to adjust for different increases to see how it impacts different cities and regions under a variety of sea level and high tide rise scenarios .

Note: The map does not account for future preventative members like the erection of sea walls.

States with the greatest populations in harm’s way of a sea level rise:

  • Florida
  • Louisiana
  • California
  • New York
  • New Jersey

Florida is the state with the greatest population at risk of losing their homes.There have already been many dire predictions that large parts of the Miami Metro area are doomed. So far, attempts to build sea walls and increase the elevation of buildings have not worked. The problem is that the water is beginning to saturate the limestone that provides the land for the tip of Florida, and the city is actually sinking as the sea rises.

All of  these states also have very dense populations near the sea, so it does not mean they are the only states with a lot of land area to lose. Any state with a coastline by the Atlantic, Pacific, or Gulf of Mexico faces the same threats. Of course this includes Texas and other Gulf Coast state, the Pacific coast, and the Atlantic coast.

Most of these percentages are calculated by the number of residents, and they are not calculated by the square miles of land lost. Of course, the loss of many square miles of land could mean the loss of agriculture, ports, industry, and much more.

Will Sea Level Rise Predictions Come True?

Even the folks at Climate Central caution against taking predictions for any one area as something engraved in stone. However, they do say that when spread over all areas, these predictions are likely to average out as close to correct. For example, they may have overestimated the threat to one city, or not accounted for future preventative measures, but it is likely they were too conservative in other areas. For comparison, this is similar to estimating an athlete’s performance over all games and not just one.

Past Sea Level Increases

According to the Climate Change organization, global temperature changes have increased average sea levels by about 8 inches since the 1880’s, but the rise is now accelerating. Of course, various weather patterns means that the rise is slow some years and catastrophic in others. In other words, the loss of dry land doesn’t just come in a steady line on a graph but in a more jagged one.