The United Nations has warned that glaciers in Yosemite and Africa will disappear by 2050


The United Nations Educational, Scientific and Cultural Organization warned in a new report Thursday that glaciers in at least a third of its World Heritage sites, including Yosemite National Park, will disappear by mid-century even if emissions are curbed.

Even if global warming were limited to just 1.5°C (2.7°F), which now seems unlikely, all of Yosemite’s glaciers and glaciers in Yellowstone National Park, as well as the few remaining glaciers in Africa, would be lost.

In its report, the United Nations Educational, Scientific and Cultural Organization (UNESCO) warned that other glaciers can only be saved if “greenhouse gas emissions are significantly reduced” and global warming is capped at 1.5 degrees Celsius.

Melting glaciers in the world reveal their secrets very quickly

At about 50 of the organization’s more than 1,150 World Heritage sites, there are glaciers, which together make up nearly a tenth of the world’s glacier area.

Nearly 19,000 glaciers located in heritage sites are losing more than 60 billion tons of ice annually, UNESCO said, which is equivalent to the annual water consumption of Spain and France combined, and represents about 5 percent of global sea level rise.

“Glaciers are retreating at an accelerating rate all over the world,” said Tales Carvalho Resende, a UNESCO hydrologist.

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

Besides the significant reductions in emissions, the UNESCO report calls for better monitoring of glaciers and the use of early warning mechanisms to respond to natural disasters, including floods caused by erupting glacial lakes. Such a flood already cost thousands of lives It may have partially fueled the disastrous floods in Pakistan this year.

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While there have been some local attempts to reduce melt rates – for example, by Ice blankets – Carvalho Resende cautioned that scaling up these experiments “could be very difficult, due to costs but also because of the inaccessibility of most glaciers.”

Throughout history, glaciers have grown during very cold periods and have shrunk when those extensions have ended. The world’s last extreme cold period ended over 10,000 years ago, and some natural thaw was expected in Europe After the end of the last “Little Ice Age” in 19th century.

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

While the additional thawing has somewhat offset other effects of climate change — for example, keeping rivers from drying out despite heat waves — it is quickly reaching a critical threshold, according to UNESCO.

In the Würkel glacier in Switzerland, scientists are able to discover ancient artifacts where the ground was once frozen. (Video: Rick Nowak/The Washington Post)

The organization wrote in its report that the peak in the meltwater may have already passed over many smaller glaciers, where the waters are now starting to dwindle.

If this trend continues, the organization warned, “little baseline flow will be available during droughts.”

The changes are expected to have major implications for agriculture, biodiversity and urban life. UNESCO writes that “glaciers are vital sources of life on Earth”.

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“They provide water resources for at least half of humanity,” said Carvalho Resende, who warned that the cultural losses would also be enormous.

Worldwide, global warming Expose ancient artifacts Faster than archaeologists can save.

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

UNESCO cited the example of the centuries-old Snow Star Festival in the Peruvian Andes, already affected by the loss of ice. Spiritual leaders once shared ice blocks with pilgrims, but the practice was discontinued when locals noticed a rapid decline in recent years.

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Small glaciers at low or medium altitudes will be the first to disappear. Unesco said rates of ice loss in small glaciers “more than doubled from the early 2000s to the late 2010s”.

This matches observations of researchers who study glacier retreat. European glaciologist Matthias Haas said scientists have seen “very strong melting in the past two decades” in Switzerland.

At the same time, there are fewer and fewer places cold enough for glaciers to actually grow. At present, the maximum at which glaciers can form new ice is about 3000 meters [about 9,840 feet]He said, explaining that in recent decades this height has risen by several hundred meters.

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