CLIMATE CHANGE: IT’S WORSE THAN WE FEARED

The IPCC may also have been too cautious on Greenland,assuming that the melting of its glaciers would contribute little to sea-level rise. Some studies found that Greenland’s glacial streams were surging and surface ice was morphing into liquid lakes,but others made a strong case that those surges and melts were aberrations,not long-term trends. It seemed to be a standoff. More reliable data,however,such as satellite measurements of Greenland’s mass,show that it is losing about 52 cubic miles per year and that the melting is accelerating. So while the IPCC projected that sea level would rise 16 inches this century,“now a more likely figure is one meter (39 inches) at the least,” says Carlson. “Chest high instead of knee high,with half to two-thirds of that due to Greenland.” Hence the “no idea how bad it was”.

The frozen north had another surprise in store. Scientists have long known that permafrost,if it melted,would release carbon,exacerbating global warming,which would melt more permafrost,which would add more to global warming,on and on in a feedback loop. But estimates of how much carbon is locked into Arctic permafrost were,it turns out,woefully off. “It’s about three times as much as was thought,about 1.6 trillion metric tonnes,which has surprised a lot of people,” says Edward Schuur of the University of Florida. “It means the potential for positive feedbacks is greatly increased.” That 1.6 trillion tons is about twice the amount now in the atmosphere. And Schuur’s measurements of how quickly CO2 can come out of permafrost,reported in May,were also a surprise: 1 billion to 2 billion tonnes per year. Cars and light trucks in the U.S. emit about 300 million tonnes per year.

In an insightful observation in The Guardian this month,Jim Watson of the University of Sussex wrote that “a new breed of climate sceptic is becoming more common”: someone who doubts not the science but the policy response. Given the pathetic (non)action on global warming at the G8 summit,scepticism that the world will get its act together seems appropriate. For instance,the G8,led by Europe,has vowed to take steps to keep global warming below 2 degrees Celsius by reducing CO2 emissions. We’re now at 0.8 degree. But the amount of CO2 in the atmosphere is already enough to raise the mercury 2 degrees. The only reason it hasn’t is that the atmosphere is full of crap (dust and aerosols that contribute to asthma,emphysema,and other diseases) that acts as a global coolant. As that pollution is reduced for health reasons,we’re going to blast right through 2 degrees,which is enough to exacerbate droughts and storms,wreak havoc on agriculture,and produce a planet warmer than it’s been in millions of years. The 2-degree promise is a mirage.

The test of whether the nations of the world care enough to act will come in December,when 192 countries meet in Copenhagen to hammer out a climate treaty. Carlson vows that IPY will finish its Arctic assessment in time for the meeting,and one conclusion is already clear. “A consensus has developed during IPY that the Greenland ice sheet will disappear,” he says.