Geoengineering Earth's Climate: Resetting the Thermostat

Geoengineering Earth's Climate: Resetting the Thermostat — page 5
to remain covered in ice and snow year-round has changed Warmer temperatures in Earth’s atmosphere are melting the top of the glacier sending rivulets of ice water into the ocean Warming waters of the North Atlantic Ocean are melting the glacier from the bottom as well The melting glacier on the Evigheds Fjord is part of a much larger formation called an ice sheet Earth has two major ice sheets one on Greenland and one on Antarctica Measuring more than 660,000 square miles 1 7 million square kilometers Greenland’s ice sheet is approximately the size of Texas On average the ice sheet is 1 mile 1 6 km deep Its greatest depth is 3 miles 4 8 km If it were to melt entirely the total amount of water it contains would raise the oceans by about 23 feet 7 meters The rising waters would flood the coasts of every country on the planet and submerge many inhabited islands While the probability of the entire Greenland ice sheet melting is slim climatologists scientists who study Earth’s climate note that Greenland is shedding more ice during summer than it regains from snowfall in winter The US National Aeronautics and Space Administration NASA reports that Greenland’s ice sheet is losing about 31 billion tons 28 billion metric tons of ice annually Some of the melting ice evaporates turns into water vapor or stays on the land but most of it goes directly into the ocean And studies show that the melting on Greenland is increasing every year NASA uses satellites to measure the depth of Earth’s oceans The agency has noticed a definite rise in ocean levels over the last century with an average yearly rise of about 0 13 inches 3 3 millimeters While that may seem small it adds up to a 4 to 8-inch 10 to 20-centimeter rise over the past one hundred years If that water were lying in the street it could flow over curbs and into houses If you were standing next to the ocean the rising water would cover your legs to mid-calf Imagine that much water flooding the entire world And if the ice sheets continue to melt the water levels will only get higher NASA climate scientist Jay Zwally says that the melting of 8 G e o e nGi n e e r i nG e a r t h s c l i m a t e