The Arctic is getting warmer faster than almost anywhere else on Earth. The latest evidence came in an announcement from the University of Colorados National Snow and Ice Data Center saying that, as of Aug. 26, the Arctic sea ice cover shrank to 1.58 million square miles this summer, the smallest area since satellite measurements began in 1979. The trend is expected to continue in the next few weeks.
Over the past three decades, the average extent of the Arctic sea ice has declined by 25 to 30 percent, and the rate of decline is accelerating. In the past, older, thicker ice would drift away and be replaced by seasonal ice. But now more of the older ice is melting in the Arctic, a phenomenon that had been relatively rare. Also, less seasonal ice is replacing it.
Whats alarming is that in recent years scientists have detected a feedback effect: The seasonal sea ice melts more quickly, and the decline results in more heat absorption by open water, which in turn leads to more warming.
The sea ice is not the only part of the Arctic cryosphere that is melting. Overall, in the past 30 years, the rise in annual average temperatures has been twice as high over the Arctic as over the rest of the world. Evidence from lake sediments, tree rings and ice cores suggests that Arctic ice temperatures have been higher in the past few decades than at any time in the past 2,000 years.
The implications of this are profound, not only as an indicator of global climate change but also of changes in sea levels, freshwater, the Earths energy balance, the biosphere and the livelihoods of millions of people.
Climate change is happening, yet humans have been terribly slow to curb fossil fuels that emit greenhouse gases and cause the atmosphere to warm. The United States, caught in political gridlock and lacking consensus on the global-warming threat, has failed to take the lead. The latest reports of the shrinking Arctic ice should shock Congress and the president into more aggressive action, but both branches of government have been timid in the face of one of the great challenges of our age – and one that will haunt future generations.
Within this century, and perhaps in the next 30 or 40 years, the Arctic is projected to become nearly ice-free in the summer. A benefit may be that trans- polar shipping routes from Europe to the Pacific will be 40 percent shorter, and choke points like the Suez and Panama canals could lose their significance. But there is also potential for conflict over borders, oil and mineral extraction, and jockeying among military forces.
The Arctic promises to be getting hot in more ways than one.