One of the obvious signs of global warming is the rise of sea levels around the world. Most of the world’s population lives near an ocean. The rise is caused by three different factors. First is the melting of the glaciers around the world, in particular, Greenland and Antarctica. Rain which puts more water into rivers and oceans near the river mouth. Third is the heat causes the ocean water to expand raising seas.

            Coastal cities around the world are either building defenses or planning how to avoid flooding. Many years ago London built a system of moveable gates to close off the Thames River. Venice has built the same system. New York City needs a larger and deeper system costing well over 3 billion. Charleston’s looking to build a dike around most of the city similar to New Orleans. Miami is having new buildings built higher and turning ground floors of others into basements by raising streets. These plans and projects are an expensive stop-gap for a rise of a few feet from extra high tides, or a small surge from a hurricane. They won’t help with 20 foot rises by 2100 or 200 to 300 foot rise by sometime in 2300. The problem with the computer models is they have been conservative thus far.

            Flooding of the coastal areas is going to happen no matter what we do to reduce CO₂ in the atmosphere. The glaciers will continue to melt and the oceans will expand. We are already on the flooding escalator; we just don’t know how high it will go. As we build dikes to make small island cities, where will those outside the walls go? Tens of millions of Americans will be moving inland. Washington D.C. will again be a real swamp causing the capital to move inland.