Glaciers in Yosemite and Africa to disappear by 2050, UN warns
Other glaciers can only be saved if greenhouse gas emissions are “drastically cut” and global warming is limited to 1.5 degrees, Paris-based UNESCO warned in a report.
About 50 of the organization’s more than 1,150 World Heritage sites have glaciers, which together account for nearly a tenth of the world’s glacial area.
The almost 19,000 glaciers located in the heritage sites lose more than 60 billion tons of ice a year, which is the annual water consumption of Spain and France combined, and accounts for about 5 percent of global sea level rise, UNESCO said.
“Glaciers are retreating at an accelerated rate around the world,” said UNESCO hydrology expert Tals Carvalho Resende.
The organization described a “warming cycle” in which melting glaciers create darker surfaces, which then absorb more heat and accelerate ice retreat.
In addition to drastically reducing emissions, the UNESCO report calls for better monitoring of glaciers and the use of early warning mechanisms to respond to natural disasters, including floods from glacial lakes. Such floods have already occurred cost thousands of lives and may have partly fueled Pakistan’s disastrous floods this year.
While there have been some local attempts to reduce melting rates, such as by covering the ice with blankets — Carvalho Resende warned that scaling up those experiments “could be extremely difficult because of the costs, but also because most glaciers are really hard to access.”
Throughout history, glaciers have grown during very cold periods and shrunk when those sections ended. The world’s last very cold period ended more than 10,000 years ago, and subsequent natural thawing was expected In Europe after the end of the last Little Ice Age 19th century.
But as carbon dioxide emissions rose over the past century, human factors began to accelerate what was expected to be a gradual natural retreat. In Switzerland, glaciers have lost a record 6 percent of their volume this year alone.
While the additional melting has somewhat offset other effects of climate change, such as preventing rivers from drying up despite heat waves, it is quickly reaching a critical threshold, according to UNESCO.
In its report, the organization writes that the peak meltwater may have already been transferred to much smaller glaciers, where water is now beginning to recede.
If the trend continues, the organization warned, “there will be little or no baseflow during dry periods.”
The changes are expected to have serious consequences for agriculture, biodiversity and urban life. “Glaciers are important sources of life on Earth,” UNESCO wrote.
“They provide water resources to at least half of humanity,” said Carvalho Resende, who warned that cultural losses would also be huge.
It’s global warming all over the world uncovering ancient artifacts faster than archaeologists can salvage them.
“Some of these glaciers are sacred sites that are really important to indigenous peoples and local communities,” he said.
UNESCO gave the example of the centuries-old Snow Star Festival in the Peruvian Andes, which has already suffered from the loss of ice. Spiritual leaders once shared blocks of glacier ice with pilgrims, but the practice was discontinued when locals noticed the rapid retreat in recent years.
Small glaciers at low or medium altitudes will disappear first. UNESCO says the rate of ice loss in small glacier areas “more than doubled between the early 2000s and the late 2010s”.
This matches the observations of researchers who have studied the retreat of glaciers. Matthias Huss, a European glaciologist, says scientists in Switzerland have seen “very strong melting over the last two decades”.
Meanwhile, there are fewer and fewer places cold enough for glaciers to actually grow. “Today, the border of the glaciers, where new ice can still form, is about 3,000 meters. [about 9,840 feet]”, he said, explaining that during the last decades, that height has increased by several hundred meters.
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