Geoengineering Earth's Climate: Resetting the Thermostat
there there ONE AN ABRUPT CHANGE IN CLIMATE RISING SEAS Flooded islands Catastrophic droughts tornadoes and hurricanes Scientists say that these trends which have been increasing in the twenty-first century are caused by climate change created by the warming of Earth Most scientists also say that humans have caused climate change by burning fossil fuels coal petroleum and natural gas which release heat-trapping gases into the atmosphere As levels of these gases increase the planet grows warmer The higher temperatures have led to extreme weather events Most experts agree that if humans don’t take action to prevent
Earth from warming further the climate will undergo even more drastic changes And these will ultimately affect every living thing on Earth What can humans do to counteract climate change Some engineers propose using geoengineering to tackle the problem The prefix geo means relating to Earth so geoengineering means engineering Earth A more formal definition of geoengineering is the active transformation of Earth’s climate through human intervention or using technology to reverse the effects of climate change Sounds good right Maybe so But geoengineering is one of the most complex and controversial topics in the world Messing with Earth’s climate is a big deal and could have lasting consequences both positive and negative CRA-CK Tiny cracks have appeared in a glacier a large body of moving ice along Evigheds Fjord in western Greenland In the past ice and snow completely covered the towering mountains that surround the fjord But in the twenty-first century dense rock is visible underneath the ice The extremely cold weather that allows Greenland’s coastal mountains Chunks of ice break off a glacier on the southeastern coast of greenland and fall into the Denmark Strait Warmer air and water temperatures are melting ice in earth’s polar regions causing sea levels to rise An Abrupt ChAnge in ClimA te 7
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
NORTH AMERICAN COASTLINES BEFORE AND AFTER PROJECTED MELTING OF EARTH’S ICE NORTH AMERICA P A C I F I C O C E A N Existing coastlines Landmass after melting A T L A N T I C O C E A N SOUTH AMERICA Sea levels have already begun to rise due to global warming if all the polar ice on earth were to melt large areas of coastline would end up underwater this map shows what north America would look like in that case Florida would be submerged along with vast stretches of coast along the Atlantic ocean and the gulf of mexico Greenland’s ice sheet is like a canary in a coal mine Before coal mines used modern air-quality detectors miners sometimes took live canaries with them into mineshafts If the birds stopped singing miners knew that deadly carbon monoxide which is frequently found inside coal mines had risen to dangerous levels and killed the birds Miners then knew it was time to hightail it out of the shaft Climatologists think of Greenland as a canary or an early warning system for the rest of the planet Since the Greenland and Antarctic ice sheets account for almost 99 percent of all freshwater ice on the planet An Abrupt ChAnge in ClimAte 9
