Glaciers in Yosemite and Africa will disappear by 2050, warns UN


PARIS — Glaciers in at least a third of World Heritage sites that have them, including Yosemite National Park, will disappear by mid-century even if emissions are reduced, the United Nations has warned for education, science and culture in a new report Thursday.

Even if global warming is limited to just 1.5 degrees Celsius (2.7 degrees Fahrenheit), which now seems unlikely, all of Yosemite’s glaciers and the ice sheets of Yellowstone National Park, as well as the few glaciers remaining in Africa, will be lost.

Other glaciers can only be saved if greenhouse gas emissions are ‘significantly reduced’ and global warming is capped at 1.5 degrees Celsius, Paris-based UNESCO warned in its report .

“This report is a call to action,” UNESCO Director-General Audrey Azoulay said in a statement and linked the report to the UN Climate Change Conference, known as COP27. , which is expected to start in Egypt next week. “COP27 will have a crucial role in helping to find solutions to this problem.”

The world’s melting glaciers are giving up their secrets too quickly

About 50 of the organization’s more than 1,150 World Heritage Sites have glaciers, which together make up almost a tenth of the world’s glacier surface.

The approximately 19,000 glaciers on heritage sites lose more than 60 billion tonnes of ice per year, which is equivalent to the annual water consumption of Spain and France combined and represents around 5% of the elevation global sea level, said UNESCO.

“Glaciers are retreating at an accelerating rate around the world,” said UNESCO hydrology expert Tales Carvalho Resende.

The organization described a “warming cycle” in which melting glaciers cause darker surfaces to emerge, which then absorb even more heat and accelerate the retreat of ice.

Along with drastic emission reductions, the UNESCO report calls for better monitoring of glaciers and the use of early warning mechanisms to respond to natural disasters, including flooding caused by the bursting of glacial lakes. Such floods have already costs thousands of lives and may have partly fueled Pakistan’s catastrophic floods this year.

Although there have been some local attempts to reduce fusion rates – for example, by cover the ice with blankets – Carvalho Resende warned that scaling up these experiences “could be extremely difficult, because of the costs, but also because most glaciers are really difficult to get to”.

Throughout history, glaciers grew during very cold spells and shrank when those stretches ended. The world’s last very cold period ended more than 10,000 years ago, and a new natural melt was expected in Europe after the end of the last “little ice age” in the 19th century.

But as carbon dioxide emissions increased over the past century, human factors began to accelerate what was supposed to be a gradual natural decline. In Switzerland, glaciers have lost a record 6% of their volume this year alone.

While the additional melting has to some extent offset other impacts of climate change – for example, preventing rivers from drying up despite heat waves – it is rapidly reaching a critical threshold, according to UNESCO.

In the Forcle Glacier in Switzerland, scientists are able to uncover ancient artifacts where the land was once frozen. (Video: Rick Noack/The Washington Post)

In its report, the organization writes that the meltwater peak may have already been exceeded on many smaller glaciers, where the water is now beginning to recede.

If the trend continues, the organization warned, “little or no base flow will be available during drying periods.”

The changes are expected to have major ramifications for agriculture, biodiversity and urban life. “Glaciers are crucial 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 immense.

Around the world, global warming is exhibit old objects faster than they can be saved by archaeologists.

“Some of these glaciers are sacred places, which are really important to indigenous peoples and local communities,” he said.

UNESCO cited the example of the centuries-old Festival of Snow Stars in the Peruvian Andes, which has already been affected by melting ice. Spiritual leaders once shared blocks of glacier ice with pilgrims, but the practice was halted when locals noticed the rapid retreat in recent years.

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Small glaciers at low or medium altitude will be the first to disappear. UNESCO said rates of ice loss in small glacial areas “more than doubled between the early 2000s and late 2010s”.

This corresponds to the observations of researchers who have studied the retreat of glaciers. Matthias Huss, a European glaciologist, said scientists had observed “very strong melting over the past two decades” in Switzerland.

At the same time, there are fewer and fewer places cold enough for glaciers to actually grow. “Today, the limit where glaciers can still form new ice is around 3,000 meters [about 9,840 feet]“, he said, explaining that in recent decades this altitude has increased by several hundred meters.

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