By measuring the thickness and movement of over 250,000 mountain glaciers through new satellite imaging techniques, scientists have determined that these shrinking glaciers contain even less ice than we had believed. Some ice streams are hundreds of thousands of years old, and almost fifty percent will vanish by the end of the century.
When the world breaches the 1.5 Celcius temperature rise from pre-industrial times, which scientists had warned in the Paris accords, we must not ever pass due to catastrophic consequences, which could happen this year (at least temporarily). We would lose 104,000 glaciers as a result. The freshwater from melting would raise sea levels by 3.5 inches.
My friends, that is the best-case scenario we could hope for in our rapidly warming world. For humanity, the sea-level rise generated by meltwater in marine-terminating glaciers is the least of our concerns. Two billion people depend on mountain ice for agriculture, drinking water, bathing, and energy generation.
The loss of fifty percent of glaciers will be twenty-six percent of the volume of mountain glaciers. That is because those glaciers are much smaller and will be the first to disappear entirely. And disappear they will because they contain even less ice than we thought. Mass migration will happen in some areas of the world as a result. Water is life; if it can no longer sustain biodiversity and human populations, lifeforms will either need to flee or die from dehydration.
Todd Woody writes in Bloomberg Green.
The survey encompassed 98% of areas on Earth that were covered in glaciers from 2017 to 2018. It found wide variations in ice volume and freshwater reservoirs that hundreds of millions of people depend on for drinking water, agriculture and electricity generation. That includes glaciers never before mapped in areas of New Zealand, South America and Europe, according the paper published in the journal Nature Geoscience on Monday.
Researchers at France’s Institute of Environmental Geosciences and Dartmouth College determined that the Himalayas held 37% more ice than past surveys had found while the Andes in South America contained 27% less.
There is good news if you can believe it.
Those findings could be relatively good news for the 8 million people that live in the upper Indus and Chenab basin of the Himalayas who rely on glacier meltwater for more than half of river flow during dry seasons. The study estimated that glacier water reservoirs there are 17% to 31% larger than thought. Researchers also calculated that glacial water reservoirs are 30% to 87% larger in a less populated sub-basin of the Brahmaputra River in the Himalayas.
But the Himalayas are the exception.
For instance, the 4 million people who live in three catchment basins of the tropical Andes mountains could face water shortages earlier than expected. The scientists discovered that glaciers in that region hold 20% less ice on average than previously estimated and are among the fastest melting.
In this study, sea level rise will be reduced by three inches due to improved satellite imagery on ice volume, not due to a change in the rate of surface warming.
E and E-News report on the loss of glaciers outside Greenland and Antarctica; Half of All Mountain Glaciers Are Expected to Disappear by 2100. The story is not behind a paywall, but you must create an account to read it.
The new study examines all of Earth’s glaciers outside of the Greenland and Antarctic ice sheets. That includes mainly mountain ice stretching across Alaska and Canada, the European Alps, High Mountain Asia, South America, and New Zealand.
The research incorporates many of the latest advancements in glacier modeling, allowing it to make some of the most accurate estimates yet about the ways the world’s ice could respond to future warming. It accounts for complex factors, like the way the oceans can speed up the melting of seaside glaciers.
"Regions with relatively little ice like the European Alps, the Caucasus, the Andes, or the western US, they lose almost all the ice by the end of the century almost no matter what the emission scenario is," Hock said. "So those glaciers, they're more or less doomed."
Under the worst-case scenario -- global temperature rise of 4.0C -- giant glaciers such as those in Alaska would be more affected and 83 percent of glaciers would disappear by the end of the century.
Glacier loss would also exacerbate sea level rise.
"The glaciers that we are studying are only one percent of all ice on Earth," said Hock, "much less than the Greenland ice sheet and the Antarctic ice sheet.
"But they have contributed to sea level rise almost just as much as the Greenland and Antarctic ice sheet together in the last three decades," she said.
We are not ready for what’s to come. Tic Tok.