How did the melting of natural glaciers trigger the devastating floods in Pakistan?

Most of Pakistan is now under water. A series of severe floods have completely devastated the South Asian country of 225 million people, washing away roads and buildings, destroying farms and trapping hundreds of thousands of people. Last weekend, which brought another torrential rain, government officials said the death toll exceeded 1,000 and inundated a third of the country.

The main driver of these catastrophic floods is rainfall. Summer is the monsoon season, and as we saw last month in most parts of our country, this season has been particularly wet and harmful, and the situation has probably been exacerbated by climate change. However, there is another factor behind the recent devastation: the melting of glaciers and snow.

Quoted from the Vax websitePakistan has more than 7,200 natural glaciers, more than anywhere else outside the poles. Rising temperatures associated with climate change are likely to cause many of them to melt faster and earlier, adding water to rivers and streams that are already overflowing from rainfall.

Road destruction in Swat valley in Pakistan

A highway has been damaged by floods in the Swat Valley in Khyber Pakhtunkhwa province in northwestern Pakistan.

Shri Rahman“We have the largest number of glaciers outside the polar regions and this is affecting us,” Pakistan’s weather minister told the Associated Press. He added: “Instead of preserving their greatness and preserving them for future generations and nature, we see them melting.”

As a result, Pakistan, which is already one of the most vulnerable countries to climate change, is increasingly exposed to floods due to global warming. This unfortunate reality for a country responsible for only a small fraction of greenhouse gas emissions shows how the damage from big polluters is often exported. Pakistan, like many other countries, will bear a disproportionate burden of climate change in the coming years.

Melting of ice and snow causes floods to intensify

Glaciers are dense masses of compacted ice found in mountains all over the world, from the Alaska Range to the French Alps. Shrinking and regrowing within a year (melting in summer and expanding in winter) is a natural occurrence.

But overall, glaciers have shrunk over the past few decades because they haven’t been able to recover their mass in winter. A simple reason is that the heat melts the ice and the planet is warming. Ulrik Kempa University of Michigan Dearborn professor who has been studying glaciers for nearly 20 years, says higher temperatures can also turn snow into rain, and when it rains on the ice, it speeds up melting.

A natural glacier in northern Pakistan

A natural glacier in northern Pakistan in the Gilgit-Baltistan region.

Melting of glaciers is a big problem in Pakistan. Based on A study in 2021Not only is this country a hot spot for glaciers, but the melting of glaciers in the Himalayas (one of Pakistan’s main mountain ranges) is accelerating. Jonathan Cariwick“Our findings clearly show that ice is now being lost from Himalayan glaciers at a rate at least ten times greater than the average rate over the past century,” the study’s lead author said in a statement when it was released.

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In addition to melting snow, ice runoff can cause rivers to flood even miles down the mountain, Kemp said. This is especially alarming when it coincides with the monsoons, which are likely to intensify due to climate change. Part of the reason for increased rainfall due to global warming is that warmer air can hold more water. “We will have to deal with floods as more water from melting glaciers in the coming decades due to climate change,” Kemp said.

Melting of glaciers can also cause flooding of lakes located at high altitudes

Melting ice can cause severe floods from another direction. In the mountains of Pakistan, glacier water forms high-altitude lakes, often surrounded by ice. When there is too much runoff, those lakes expand rapidly and the ice dams can break, setting off an event known as a “glacial lake outburst.”

The breaking of these natural dams is a very dangerous event. As The Washington Post reported earlier this yearIn April, one of the hottest months on record in Pakistan, a glacial lake near Mount Chisper overflowed, possibly due to rapid inundation with melting ice. Water flowed into a village in northern Pakistan and destroyed one of the bridges in the area.

Destruction of Hassan Abad Bridge on Karakoram Highway due to flooding caused by the overflowing of Lake Lakhrei.

Northern Pakistan now has more than 3,000 glacial lakes, and some of them seem to be forming earlier than usual this year due to extreme heat. According to the United Nations33 of these lakes are prone to dangerous overflow leading to floods. There have been more than ten lake floods this year, which is much higher than the annual average of 5 or 6 cases. However, it is not known to what extent these floods have aggravated the floods in recent weeks.

Rich countries are mainly responsible for the severe effects of climate change

Scientists have not yet determined what role climate change plays in floods; But it is clear that global warming puts Pakistan and many other countries at risk. Also, it is not just flooding, but heat, drought and other obvious signs of rising temperatures that are problematic. In fact, based on Global Climate Risk Index According to a German non-profit organization, Pakistan is the eighth most vulnerable country to extreme weather events.

Even if global warming is limited to 1.5°C under the ambitious goal of the Paris Climate Agreement, a third of Pakistan’s glaciers could still be lost. Glaciers can approach tipping points as they shrink, Kemp says. “Suddenly when they are very small, everything changes 180 degrees; From abundant water and floods to drought.”

To this end, Pakistan has asked rich countries to fulfill their commitment of more than a decade ago to provide 100 billion dollars annually to low-income countries to adapt to climate change. Aamir KhanPakistan’s Deputy Permanent Representative to the United Nations, during a meeting in July, said: “Developing countries, while they are not responsible for the emission of greenhouse gases today, often bear the brunt of climate change.” The special challenges that developing countries face due to climate change must be recognized.

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