Ladies and gentlemen, the captain's voice crackled over the plane's public address system. He apologised for disturbing the passengers' mid-flight slumber across the Atlantic. "If you look out of the window on the right side of the aircraft," he said, "you will have a clear view of Greenland. In my 15 years of flying, I have not seen a scene like this."
I opened the window shade, and as my eyes adjusted to the glare of ice shining in the bright afternoon sun, I understood what had so startled the pilot. Instead of the habitual snowy landscape and frozen glaciers, a wide swathe of black water was visible as it flowed into the Atlantic. It was late spring, but the giant icebox that is Greenland was already melting.
The fleeting image that I saw from 30,000 feet in early May is consistent with massive amounts of climate data gathered from across the planet. It is now clear that on average, the global surface temperature has increased by about one degree Celsius since 1900 and has been the cause of extreme climate events across the planet.
At times, warming climate combined with soot in the air thrown by wild fire has accelerated the melting. Two years ago, the National Aeronautics and Space Administration researchers were stunned to find the thawed area in Greenland had jumped from 40 per cent ice sheet to 97 per cent in just four days. Greenland, holding 10 per cent of the world's ice, is now under close watch for signs so that 2012's dramatic meltdown is not repeated.
The melting also continues unabated elsewhere. Warm weather is leading ice sheets to break up and turning glaciers into flowing streams. In May, Nasa scientists concluded that the rapidly melting glacial region of Antarctica has passed "the point of no return", threatening to increase sea levels by as much as 13 feet within the next few centuries.
The fact that the melting is taking place slowly and its effect may not be felt for a few decades seems to offer comfort to those who want to continue their lifestyle relying on fossil fuels. Unwilling to believe in global warming or make the sacrifices needed to face the challenge, politicians have been finding excuses to do nothing.
American President Barack Obama, not hobbled by the need to fight elections, has now broken ranks with such politicians. Unable to pass legislation in the face of Republican (and sometimes Democratic) opposition, he instructed the Environmental Protection Agency to announce regulatory policies to curb emissions from power plants in the United States by 30 per cent by 2030.
He hopes that regulations would influence the US states to adopt aggressive market interventions to address global warming. Only by making pollution expensive and providing economic incentives to use cleaner energy, can one break the habit of dirty coal and polluting oil. Of course, execution of the policy still lies in the hands of many state governors who would find ways to resist, saying that regulations would raise the cost to the economy and cause unemployment among coal workers.
As President Obama told Thomas Friedman of the New York Times: "One of the hardest things in politics is getting a democracy to deal with something now where the payoff is long term or the price of inaction is decades away."
The price of inaction could be raised - and made more imminent - if the coming global summit on climate in Paris could do what other summits have failed to do: agree on a fixed target for greenhouse gas emissions and a rigorous system for monitoring.
China has hinted at capping coal burning in the next 15 years, adding weight in favour of action.
India, the world's third largest user of coal, which during the last Copenhagen summit got China's backing to resist demands for cuts, may have to take measures on its own or face isolation.
Meanwhile, melting in Greenland and the Antarctica will continue as the sun scorches the fields and rising water threatens the coastal areas.
The writer is editor-in-chief of YaleGlobal Online, published by the MacMillan Center, Yale University, and sits on the university's Council on Southeast Asia Studies.