Paris-based UNESCO warned in a report that other glaciers can only be saved if greenhouse gas emissions are “significantly reduced” and if global warming is kept to 1.5 degrees Celsius.
The world’s melting glaciers are revealing their secrets very quickly
About 50 of the organization’s more than 1,150 World Heritage sites have glaciers, which together make up about a tenth of the world’s glacier area.
UNESCO says the nearly 19,000 glaciers in the World Heritage Sites lose more than 60 billion tons of ice a year, equivalent to the annual water consumption of Spain and France and accounting for about 5 percent of global sea level rise.
“The glaciers are retreating at a rapid rate around the world,” said Tales Carvalho Rezende, a UNESCO hydrologist.
The organization described a “warming cycle” in which melting glaciers lead to darker surfaces, which then absorb even more heat and accelerate ice retreat.
In addition to drastic 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 bursting glacial lakes. Such floods have already killed thousands of people and may have partially caused the catastrophic floods in Pakistan this year.
While there are some local efforts to reduce the level of melting – for example by covering the ice with blankets – Carvalho Rezende warned that scaling up these practices “could be very difficult because of the costs, but also because of the lack of access most glaciers are really hard.”
Throughout history, glaciers grew during periods of extreme cold and then receded when these periods ended. The world’s last very cold period ended more than 10,000 years ago, and another natural thaw was expected in Europe after the end of the Little Ice Age 19th century.
But as carbon dioxide emissions have increased over the past century, human factors have accelerated what was expected to be a gradual natural retreat. In Switzerland, glaciers have lost 6 percent of their volume this year alone.
Although the additional melting has somewhat offset other effects of climate change, such as preventing rivers from drying up despite heat waves, it is rapidly reaching critical thresholds, according to UNESCO.
In its report, the organization writes that peak meltwater may have already passed through smaller glaciers, where water is now receding.
If this trend continues, the organization warned, “there will be little or no base flow available during periods of drought.”
The changes are expected to have significant impacts on agriculture, biodiversity and urban life. “Iceans are an important source of life on Earth,” UNESCO wrote.
“They provide at least half of humanity with water resources,” said Carvalho Rezende, who warned that cultural losses would also be huge.
Around the world, global warming is exposing ancient artifacts faster than archaeologists can save them.
“Some of these glaciers are sacred places that are really important to indigenous people and local communities,” he said.
UNESCO gave the example of the centuries-old snow star festival in the Peruvian Andes, which has already been affected by the loss of ice. Spiritual leaders once shared blocks of glacial ice with pilgrims, but this practice was stopped when local people noticed the rapid retreat in recent years.
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Small glaciers at low or medium altitude are the first to disappear. UNESCO said the rate of ice loss in small glacier areas “more than doubled between the early 2000s and the late 2010s.”
This is consistent with the observations of researchers who have studied the retreat of glaciers. Matthias Huss, a European glaciologist, said that scientists in Switzerland had observed “very intense melting in the last two decades”.
Nowadays, there are fewer and fewer places that are cold enough for glaciers to actually grow. “Currently, the limit at which glaciers can form new ice is about 3,000 meters. [about 9,840 feet]”, he said and explained that in the last decades this height has increased by hundreds of meters.