Why Are My Feet Wet?
Everyone has long since tired of all the talk about global warning and what it will do to the weather. We all know the weather will get wilder as swings between bitterly cold winters and blistering-hot summers are punctuated by progressively more powerful and damaging storms in both halves of the year. We have heard all about it many times, but how many of us have heard much about the rising sea level?
As it turns out, sea level and climate are closely linked. For whatever reason, pollution or natural causes, the Earth’s mean temperature has risen about 1° Celsius (1.8° Fahrenheit) in the last 100 years.
Part of this warming is a return to temperatures that preceded the “Little Ice Age” of the 19th century, and part could be the normal warming and cooling cycle the planet has had for millions of years. Okay, and yes, part of it is our fault. In any case, as a result of this warming, the sea level has been rising about 0.2-0.5 inch (1-2 millimeters) per year.
This is going on because ice caps, ice fields, and glaciers have been slowly melting and because the oceans themselves are warming and the water is expanding thermally. If this trend continues, most of the ice on earth will disappear. For instance, most American glaciers could be gone by 2150 and Iceland’s could disappear by 2200.
This sounds like a lot of water to go into the sea but, if all the glaciers and small ice caps in the world disappear, the combined added water will only raise the mean sea level by about 1.5 feet (.45 meter). The big increases would come from the poles, in particular, Antarctica. While the sea levels would not rise all at once, there could be some rapid surges upward as big chunks of Antarctic ice break off and rejoin the sea. We’ve already witnessed a huge portion of the Ross Ice Shelf doing exactly that.
Most of the world’s ice is locked up in Antarctica. If all the world’s ice disappears, sea level could rise by 263 feet (80 meters). Greenland’s ice would raise sea levels by 21.5 feet (6.55 meters). Antarctica alone would cause most of the trouble; its ice could cause a potential sea level rise of about 240 feet (73.3 meters).
Now we’re talking major problems on the coasts of every continent. All the great seaports would be underwater and the coastlines on every continent would change dramatically. Much of Florida would disappear beneath the sea taking with it Miami, Tampa, Key West, and Disney World. The eastern seaboard would move westward many miles and wipe out New York, Boston, Baltimore, Charleston and Washington D.C. and St Petersburg.
Cajuns of coastal Louisiana would have to move a long way inland because their bayous would become part of the Gulf of Mexico. London, Copenhagen, Amsterdam, Venice, Shanghai and many others of the world’s major cities would be gone. Stuff like this makes you realize how many of our biggest cities are right on the coast, doesn’t it?
There is evidence all over the world that sea level changes have happened before. At the height of the last ice age, 20 thousand years ago, sea level was roughly 410 feet (125 meters) below what it is today because so much of the world’s water was locked up in land ice. When the climate warmed, a lot of that water returned to the sea and things like the Bering land bridge that joined Siberia and Alaska vanished.
We are currently in what is known as an interglacial period, a time when the climate warms and sea levels rise as ice caps and glaciers disappear. During previous interglacials, sea levels have been 10-66 feet (3-20 meters) higher than what they are now. It varies with how warm it got during any one interval. How do we know this?
There are indicators all over the world; cliff terraces at sea’s edge show where waves cut away at an ancient higher shorelines, marine fossils where there is now near-coastal land, ice cores that show ancient plant life on Antarctica and in Greenland where miles-deep ice now exists, and a host of other forensic clues all give away the changing faces of our land and sea. While heated debate continues over when the sea levels changed, there is none at all about whether they ever did. Everyone agrees; ample evidence shows that sea levels have been both significantly higher and lower than they are now.
So what can we do? Perhaps nothing. This may be all part of the Earth’s natural cycle of warming and cooling and we must adjust as the situation demands. If we are even partly responsible for global warming, we can take strong measures to reverse the damage we do and we had better be quick about it. The clock is ticking and the water is on the rise. Why are my feet wet?