Climate change has world skating on thin ice

by Lester R. Brown - World Watch Institute

Atmospheric CO2 levels, estimated at 280 parts per million before the Industrial Revolution, have climbed from 317 ppm in 1960 to 368 ppm in 1999—a gain of 16 percent in only four decades. As CO2 concentrations have risen, so too has Earth’s temperature. Between 1975 and 1999, the average temperature increased from 13.94 degrees Celsius to 14.35 degrees, a gain of 0.41 degrees or 0.74 degrees Fahrenheit in 24 years. The warmest 23 years since record keeping began in 1866 have all occurred since 1975. 

Two recent studies by two Norwegian scientists and a team of four U.S. scientists provide evidence that the Earth’s ice cover is melting at an accelerating rate:

An ice-breaker cruise ship discovered open water at the North Pole in mid-August. The Arctic Ocean ice has thinned by 40 percent in some 35 years. Within 50 years, the Arctic Ocean could be ice-free during the summer.

Greenland is experiencing a net loss of 51 billion cubic meters of water each year, an amount equal to the annual flow of the Nile River. 

The Antarctic ice shelves, the portions of the continent’s ice sheet that extend into the surrounding seas, are in full retreat. From mid-century through 1997, 7,000 square kilometers were lost as the ice sheet disintegrated. But then within scarcely a year they lost another 3,000 square kilometers. Delaware-sized icebergs that have broken off are threatening ships in the area. 

The snow/ice mass is shrinking in the world’s major mountain ranges: the Rocky Mountains, the Andes, the Alps, and the Himalayas. The result of such glacial melting is more flooding during the rainy season and less snowmelt to feed rivers during the dry season. This will affect the water supply for cities and for irrigation in areas dependent on snowmelt to feed rivers.

Over the last century, sea levels rose by 20-30 centimeters (8-12 inches). The existing climate models indicate it could rise by as much as 1 meter during this century. 

Ice melting itself can accelerate temperature rise. As snow/ice masses shrink, less sunlight is reflected back into space. With more sunlight absorbed by less reflective surfaces, temperature rises even faster and melting accelerates.

There may still be time to stabilize atmospheric CO2 levels before continuing carbon emissions cause climate change to spiral out of control. World Watch recommends incorporating the cost of climate disruption in the price of fossil fuels in the form of a carbon tax. Investment would then quickly shift from fossil fuels to climate-benign energy sources such as wind, solar and geo-thermal. 

For the full report, visit www.worldwatch.org/alerts/indexia.html.

Lester R. Brown is the president of the Worldwatch Institute based in Washington D.C. He is a regular contributor to that organization’s books and yearly reports including State of the World, a report on progress toward a sustainable society.