Report says glaciers in Yellowstone and Yosemite National Park are on track to disappear in the next 30 years

CNN
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The climate crisis affects almost every region of the world. But perhaps one of the most obvious indicators of its impact is its impact Impact on the famous glaciers on Eartha major source of fresh water supply. Glaciers were melting in high speed In recent decades, resulting in about 20% of global sea level rise since 2000.

Researchers at the United Nations Educational, Scientific and Cultural Organization have found that glaciers in a third of the planet’s most beautiful parks and protected areas will disappear by 2050 – whether global warming slows or not.

Among the glaciers on the verge of vanishing in World Heritage Sites Are those in two of the most visited and most popular parks in the United States – Yellowstone National Park, which witnessed Unprecedented flooding earlier this yearand Yosemite National Park.

The list also includes some of the largest and most famous glaciers in Central Asia and Europe as well as the last remaining glaciers in Africa, namely Mount Kenya and Mount Kilimanjaro.

Glaciers at World Heritage sites drop about 58 billion tons of ice each year, UNESCO reports, which is equivalent to the total volume of water used annually in France and Spain combined. These glaciers have already contributed nearly 5% of the world’s sea level rise in the past 20 years.

The study provides the first global assessment of both the current and future scenario of glaciers at World Heritage sites, according to Tales Carvalho Resende, project officer at UNESCO’s Natural Heritage Unit and author of the report.

“This report delivers a very powerful message in the sense that World Heritage sites are special places – places that are very important to humanity, but especially to local communities and indigenous peoples,” Resende told CNN. “Ice loss and glacier retreat are increasing, so this sends an alarming message.”

Only by limiting global warming to 1.5°C above pre-industrial levels can we save glaciers in the other two-thirds of these parks, scientists report – a climate target that recent reports say The world is far from it. The global average temperature has already risen by about 1.2 degrees since the Industrial Revolution.

Glaciers cover about 10% of the land, and provide fresh water supplies to families, agriculture, and industry downstream. Under normal conditions, it takes a thousand years to fully form; Each year, it gains mass through snow or rain, and loses mass by thawing in summer.

Melting glaciers may seem a distant problem, but Resende said it’s a serious global problem that could severely harm downstream communities. highlight deadly Pakistan floods This year, which left nearly a third of the country under water. Reports indicate that the multi-week flooding was likely caused by a combination of heavier-than-normal monsoon rains and the eruption of several glacial lakes due to the melt following the recent intense heat that engulfed the area.

“When the water melts, this water will accumulate in what we call glacial lakes; and when the water comes in, these glacial lakes may burst.” And this eruption could lead to catastrophic flooding, something we could see recently in Pakistan.

Thomas Slater, a glaciologist at the University of Leeds in London, notes that these glaciers contribute a small fraction to sea level rise compared to the amount of ice loss that the Antarctic and Greenland ice sheets could generate. Researchers like Slater have already found that those ice sheets are the main contributor to global sea level rise this century.

“While it is sad to hear that some of these glaciers can be lost, we must hope for the fact that reducing emissions can save the majority of them and avoid disrupting the water supply for the millions of people around the world who live downstream.” Slater, who has nothing to do with the UN report, told CNN.

As the rate of the climate crisis accelerates, more water will be released from the glaciers. In drought-stricken areas such as Western United StatesAn increase in melt water may be a good thing, but Resende said it’s only temporary.

Once the glacier’s peak water is reached – the maximum amount of meltwater it contributes to the system – annual runoff decreases as the glacier shrinks to the point where it is no longer able to produce its water supply.

According to the report, several small glaciers in the Andes, central Europe and western Canada have either already reached their water peak or are expected to do so in the coming years. Meanwhile, in the Himalayas, annual glacial run-off is expected to jump around 2050, before declining steadily thereafter.

The report shows that if countries fail to keep global warming below 1.5 degrees or even two degrees, the glaciers will continue to retreat. In that future, places will see significant runoff from glaciers during wet periods, with little or no flow to quell hotter and drier conditions.

“This is currently a hot topic in the research community – to see what the landscape will be after the glaciers melt,” Resende said. “Unfortunately, the glaciers will continue to melt because there is always a delay. Even if we stop or significantly reduce our emissions today, they will continue to retreat because there is this inertia – and it is very important that we can put in place adaptation measures.”

The report comes as world leaders gather in Sharm El Sheikh, Egypt, next week International climate negotiations mediated by the United NationsThe focus will be on getting countries to commit to stronger cuts to fossil fuels that would limit global warming to 1.5 degrees. They will also discuss adaptation plans to exacerbating climate extremes, including heat waves, floods and storms.

“We need to really unite ourselves, to make this 1.5 goal as feasible as possible,” Resende said. “The effects may be irreversible, so this is really a pledge to take urgent action.”