What to Look for in Global Warming: Glacial Tsunamis

While last year holds the warmest on record over land, La Nina has cooled the oceans somewhat. The real clues are the glaciers. Keep an eye out for glacial lakes bursting, sending tsunami-like destruction below. Glaciers have been rapidly losing mass worldwide. That water has to go somewhere. Sometimes ice dams it high in the mountains; other times, the lake overflows or breaks its retaining wall. When that dam breaks, nothing can stop the resultant tsunami. Below are two recent events deserving attention:

The first:

Raising world temperatures are blamed for melting ice in southern Chile that caused a glacial lake to swell and then empty suddenly, sending a tsunami-like wave rolling through a river, a scientist said Thursday. No one in the remote region was injured.
Glacier scientist Gino Casassa said the melting of the Colonia glacier, which he said were the result of rising world temperatures, filled the Cachet Lake and increased pressure on the ice sheet.
The water bored a 5-mile tunnel through the glacier and finally emptied into the Baker River on April 6.
“The remarkable thing is that the mass of water moved against the current of the river,” Casassa told The Associated Press by telephone from the Center for Scientific Studies in the southern city of Valdivia. “It was a real river tsunami.”
The lake was nearly full again by late Wednesday, he said.

That this article appeared in a Chinese newspaper is not accidental. China and countries the Himalayans feed have cause for concern. Punakha, Buhtan awaits its own fate:

High in the Himalayas, above this peaceful valley where farmers till a patchwork of emerald-green fields, an icy lake fed by melting glaciers waits to become a “tsunami from the sky.”
The lake is swollen dangerously past normal levels, thanks to the global warming that is causing the glaciers to retreat at record speed.
But no one knows when the tipping point will come and the lake can take no more, bursting its banks and sending torrents of water crashing into the valley below.

And in Nepal, there are over 3000 glacial lakes, and in the last 40 years almost as many have been formed.

By 2050, The Himalayas are expected to lose up to a fourth or more of their ice mass.

For China, there is no good news here:

Himalayan glaciers are shrinking at an average of 10 to 60 m annually, with some retreating by 74 m a year. In China, glaciers have been retreating at a rate of 5.5 per cent in the last three decades. With current climate change projections two-thirds of China’s glaciers are likely to disappear by 2050, and almost all would be gone by 2100.

After the glaciers go, desertification will follow. Those glaciers are the primary water supply for much of China and India. While much of the debate about global warming seems arcane and picky, tsunami-like floods coming from high in the mountains will certainly be an eye-catcher.