| There isn't a significant amount of land below sea level, because most of the planet's surface is already ocean and the saddle point being below sea level will flood it. Effectively, the most significant amounts of land below sea-level are nascent rift zones that haven't connected to the ocean yet. The sum total of significant depressions: * Salton Sea (~21700 km², sea surface ~70 m below sea-level) * Death Valley (~13000 km², deepest ~80m below sea-level) * Afar Depression (~200,000 km², average ~75m) * Qattara Depression (~20,000 km², average ~60m) * Lake Eyre (~9500 km², lake surface ~15m) * Dead Sea/Jordan Rift Valley (total catchment area apparently ~40000km², below sea level probably more like 10000km², Dead Sea surface ~430m) * Turpan Depression (~50,000 km², deepest ~150m) (note: quite far from the sea) * Caspian Sea (371,000 km², surface ~20m) There might be one or two basins the size of Lake Eyre I'm missing in the regions of Africa, but we're getting pretty shallow and small at that point. By comparison, the total surface area of the oceans is around 360,000,000 km² (although I think that number includes the Caspian Sea, which is basically an ocean that's been cut off from the world's oceans). Someone with access to GIS software could probably give you a good guess for the total storage of below-sea-level places on Earth. I couldn't find any calculations in my quick searching though, but the short answer is there really isn't much storage. |
Overall, if it was a life and death situation not the worst solution in the world. We are probably good till 2050 and this could add another 12 years. We get 20% of our energy from nuclear and I hope both sides see the need for it and if we can get it to 60% and reach 300 nuclear reactors & cut down prices back to 2008 levels to $3B each and help China and India build theirs we should be in a great state.