Pakistan is witnessing unprecedented floods this year, and at least one-third of the country has gone under the water. Increased glacier melting is being touted as the cause of this extreme natural disaster.
Pakistan has more than 7,200 glaciers, probably more than any other country in the world.
The evidence is unequivocal: These glaciers are melting faster and earlier than before. The ongoing flood, however, is also due to the monster of a monsoon the country has received this year.
The rainfall in Pakistan during this monsoon season has been the highest in the last three decades. Some places in the country have got rain four to eight times higher than the average.
Pakistan is one of the high climate risk countries and is experiencing a severe form of climate catastrophe. It had passed through an intense heatwave in April and May, and the monsoon downpours have been unrelenting for the last eight weeks.
Pakistan might be at present going through a climate change-caused natural catastrophe. However, all the countries in the region whose river receives water from the snow melting in the Himalayan (including Karakoram and Hindukush) mountains are increasingly facing severe flooding in the monsoon months, bursting of glacial lakes in the spring seasons, and drying up of rivers in the summer.
The Himalayan mountains have nearly 55,000 glaciers, and their snowmelt in the dry seasons feeds the ten biggest rivers in Asia — from Indus to Ganges-Brahmaputra to the Mekong to the Yangtze. Most rivers are transboundary as they are shared between two or more countries.
The cryosphere of the Himalayan mountains is known to be the water tower of the world as it is estimated to directly contribute to the water supply for at least 1.5 billion people.
The Himalayas are warming up almost 0.7 degrees C higher than the global average. The changing climate is shrinking the size of the glaciers and forcing them to retreat, and at the same time, increasing the number and volume of the glacial lakes.
A recent joint study by various government agencies and institutes of India finds that Hindu Kush Himalayan glaciers retreat almost 15 meters annually. In contrast, the retreat of glaciers in the Karakoram region is comparatively less. Several studies also confirm that climate change is shrinking the glaciers in Nepal, Bhutan, and Tibetan Plateau at an alarming rate.
The melting of Himalayan glaciers has almost doubled in the last two decades. Comparing satellite images, scientists find that the Himalayas is losing eight billion tons of ice every year, which is not being replaced by new snow.
While the glacier surface reduced by 22 centimetres annually from 1975 to 2000, the average annual loss per year increased to 43 centimetres from 2000 to 2016. If climate change is not reversed, at least one-third of the ice in this mountain range is expected to melt by the end of this century.
All the scientific evidence points towards human-caused climate change as the primary reason for the accelerated glacier melting. While climate change must take the lion’s share of the blame, high-altitude desert dust and air pollution are also partly responsible for the melting.
After Antarctica and the Arctic, the Himalayan mountains have the largest deposit of snow and ice on this planet. The rapid melting of glaciers is changing the weather pattern in the region, leading to an increased number of extreme weather events.
As the snow is melting earlier than before, there are floods in spring but less water in summer, adversely affecting the agricultural sector. The hydropower production pattern is also facing a crisis due to larger water demand in the downstream areas in the dry months, which reduces the dam’s flexibility to store more water for energy production in the winter.
Climate change has already changed the monsoon pattern, increasing the risk of more flooding in the rainy season. Moreover, the melting of snow and ice at a faster rate in the glaciers often adds to the intensity of the flood downstream, as it has done in Pakistan this time.
Along with melting snow water, the runoff from the glacial lakes also contributes to extreme flood conditions. Since the 1990s, the glacial lakes have increased in number and size, with it, more devastating glacial lake outburst floods. As the climate is warming and glaciers are rapidly melting, the frequency of these floods is expected to rise.
The significant variation in the water flow of the Himalayan rivers between seasons has also led to an increasing number of conflicts between basin countries. When a downstream country gets affected by the flood, it blames the upstream country for releasing more water than usual.
The dwindling water flow in the river system during the summer has been a common point of contention between countries sharing these rivers. The fast and early melting of glaciers brings less water to the rivers in summer, which can potentially lead to more disputes.
The Himalayan region is a climate hotspot, and South Asia is particularly vulnerable because of its geophysical location, high population density, and socioeconomic backwardness. Pakistan is presently experiencing a melting glacier-fuelled catastrophic flood, but the natural disasters in this region will not end with it.
As the UN Secretary-General has rightly warned: “Let’s stop sleepwalking towards the destruction of our planet by climate change. Today, it’s Pakistan. Tomorrow, it could be your country.”