Karen Genders, age 12, of Niagara Falls, Ont., Canada for her question:
WHAT WOULD HAPPEN IF THE ANTARCTIC ICE MELTED?
Old Andy suspects that the World's Worriers keep a list of possible disasters, perhaps to think about on sunny summer days. True, earthquakes can and do happen and sometimes a volcano erupts. But the moon is not likely to bash into the earth and the sun is not scheduled to die for quite a few billion years.
The Antarctic ice is not likely to melt in the foreseeable future. At least, this is the opinion of most responsible geologists. Nevertheless, the worldwide climate could make a dramatic change, as it has done many times in the past.
For example, suppose our average summertime temperatures became 10 degrees cooler. In most of North America, summers would be too cool to melt the winter snows. Year by year, accumulated frozen snowfalls would form spreading glaciers and there would be another ice age. This has happened four times in the past million years.
During an ice age, extra moisture is frozen in glaciers, so this water cannot return to the seas. The global sea level becomes lower, exposing extra land along the shores. Between the ice ages there were warmer spells, when melting glaciers added extra water to the seas. Then the sea level rose and slopped over the low lying shores.
At present, we are enjoying a mild global spell. Nobody is sure whether it will continue or give way to another ice age. If it leads to a warmer spell, then the lingering glaciers of the last ice age might melt and add their moisture to the rising sea level.
Antarctica is buried below about 7 million cubic miles of frozen snow.. This is enough ice to cover North America with a layer about one mile deep. If all of it melted, the global sea level would rise more than 100 feet and perhaps 300 feet.
Should such a ghastly disaster occur, the sea would drown all the low lying ocean islands and slop over the edges of the continents. Vast stretches of shore line would be submerged, and many of our coastal cities would sink into the sea.
Meantime Antarctica would be freed of its weighty ice and its land would rise higher to enjoy the warmer climate. However, a global remodeling job of this sort could not happen in a hurry. Certainly the people in the threatened areas would be warned in plenty of time to move to higher ground perhaps to the newly ice ,free polar regions.