Global Flood Maps - The World if the Ice Caps Melted

World flood maps hold a strange fascination over us. All of us hold some deep primeval fear of the oceans rising, drowning land and submerging the world. Flood myths occur time and time again in native cultures from South America to East Asia. The legend of Atlantis fascinated the ancient Greeks and the same images are used by Hollywood today. Who can forget the image of the tsunami striking in "Deep Impact" or the opening scenes of "Waterworld", where the famous Universal globe turns blue? Sea level rises are a source of fear and fascination - and you don't have to be living in the Maldives or Tuvalu to worry.

Some argue that our obsession with sea level rises is a legacy of an actual global, Biblical flood as described in the Book of Genesis. Others point to the dramatic and sudden rise in sea level that took place at the end of the last Ice Age. The English Channel was of course created at this time, drowning human settlements and flooding the great plain of "Doggerland" (now lost beneath the North Sea as the Dogger Bank). Click here for a spectacular image of the lost lands of the North Sea.

Some scientists believe that the Flood stories we find in every culture are based on the sudden and dramatic Black Sea Flood. In prehistory the Black Sea was probably a freshwater lake much smaller and lower than its current extent. Then, at some point 5,600 and 7,400 years ago it is believed that a massive flow of water, two hundred times as Niagara Falls, spilled over the Bosporus sill. The water would have flowed for three hundred days and water levels would have risen by six inches a day. Eventually 60,000 square miles (155,000 square kilometres) were flooded - an area larger than England. The theory is hotly debated among geologists.

Regardless of which side you take in the global warming debate, the fact is that if (for whatever reason) the ice caps melted we would be looking at an entirely different planet.

If the ice caps melted, what would happen? The most striking part of Al Gore's "The Inconvenient Truth" were satellite photos of Florida, New York City and the Netherlands consumed by the waves. Fortunately there are some excellent resources on the Internet that map the consequences of sea level rises. The flood maps that result are outstanding.

(1) Floods up to 14 metres

The best resource on the Internet must be the Firetree Flood Maps. The developer has taken Google Maps and Google Earth and added topographical data to model the impact of a sea level rise from 1 metre to 14 metres.

Here you can examine in granular, street by street detail, the impact of a sea level rise of up to 14 metres (46 ft). This relatively low rise has a dramatic impact - submerging all of Holland and utterly destroying major coastal cities from New York to London. Florida is immediately lost beneath the Gulf of Mexico. Cambridge in England becomes a coastal city on these flood maps. Advanced civilisation could almost certainly not survive such a catastrophe.

(2) The Real Deal - 70 metres

It is generally believed that if the Arctic and Antarctica ice caps melted in full then sea levels would rise between 70 and 80 metres. This produces some spectacular and eerie changes to the world as we know it. Large parts of Brazil are underwater, along with North West Europe and the eastern United States. This terrible sea level rise is less than the flooding that took place at the end of the Ice Age, when 100 metres of land was consumed and lost forever.

(3) Impossible Events

It is sobering to remember that despite the vastness of the earth's circumference, the depth of the crust is tiny. The Marianas Trench, the deepest point in the world's oceans, is only 11km- just under seven miles down and Mount Everest is 8.8km high, or about five and a half miles above sea level. This sea level rise website is incredibly addictive, because it allows us to toggle the levels of the world's oceans at will. All kinds of impossible scenarios can be created - unless of course there really are underground oceans waiting to break out or a comet strike that could create such outlandish flood scenarios. 2,000 metres of sea level rise would leave only the Rockies, Andes and the Tibetan plateau above water, along with Greenland and much of Antarctica. This would be a true waterworld - the ultimate flood map of a drowned Earth.

(c) All text WestOcean 2010

Link to Creative Commons Licence for the pictures