Climate change in Pakistan is expected to cause wide-ranging effects on the environment and people in as a result of ongoing, the has become increasingly volatile over the past several decades; this trend is expected to continue into the future.
Climate Change in Pakistan:
In addition to increased heat, drought and in some parts of the country, the melting of glaciers in the Himalayas threatens many of the most important rivers of Pakistan. Between 1999 and 2018, Pakistan was ranked the 5th worst affected country in terms of extreme climate caused by climate change.
Pakistan contributes little to (GHG) emissions at about less than 1%, yet it is very vulnerable to the effects of climate change. Pakistan’s lower technical and financial capacity to adapt to the adverse impacts of climate change worsens its vulnerability. and , as well as large displacement of populations are major threats faced by the country. Pakistan’s agriculture-dependent economy is especially susceptible to increasing irregularity and uncertainty over climatic conditions. Like many other South Asian nations, Pakistan is faced by high risk due to climate change effects.
A glacier is a large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity.
Effect of Climate Change on Glaciers in Pakistan since 1947:
Glaciers are the most sensitive precursors of climate change due to natural and anthropogenic reasons. It revealed that 30ºC isotherm has creeped upward by 725m higher elevation than 28 years before. Frequency and duration of heat waves both have increased by two fold. The rate of increase since 1990 has also been doubled resulting into frequent occurrence of severe thunderstorms and lightening events. As an example of anthropogenic change in climate, ever fastest rate of glacial depletion is presented on Siachen glacier which has lost about 2 km of its length and 17% of ice mass since 1989. Surface velocity of the glacier has also increased considerably due to the interacting warmer atmosphere with frozen water reserves in the presence of large human concentration. Projected future temperatures would further exaggerate the ice depletion and drift related dynamic processes making the situation more and more complex for the planners and dependents.
Glaciers in Pakistan:
Pakistan has some of the world’s highest and most spectacular mountains. A total of 13 of the world’s 30 tallest peaks are located there, including K2 (8,611 m), the second highest peak in the world, Nanga Parbat (8,125 m), the ninth highest peak, and Tirich Mir (7,690 m) in the Hindu Kush. Because of the numerous high mountains, and abundant precipitation characteristic of a monsoon climate, the mountains of northern Pakistan, including the Hindu Kush, Hindu Raj, Kohistan ranges, Nanga Parbat massif, and Karakoram Himalaya 3, host some of the largest and longest mid-latitude glaciers on Earth. The glacierized area in northern Pakistan is estimated to cover 15,000 km2, and as much as 37 percent of the Karakoram region is covered by glaciers.
Melting of Glaciers:
According to various studies, with 7250 discovered glaciers, no country on earth outside the polar region has more glacial ice than Pakistan. These glaciers are of immense importance for the country as the rivers that feed on glaciers make up about 75% of the stored water supply of the country. These facts speak for itself about the dependency of the country on its glaciers.
Over the last seven years, several places, including Gilgit Baltistan and Chitral Valley, have experienced numerous major floods that many studies have given credits to the climate change.
Countless lives have been laid to waste because of the floodwaters and has also taken away a living place from thousands of people. The undercutting of the once-flamboyant tourist industry is also a major negative impact caused by the overflow of water caused by the melting of glaciers. Batura glacier is one of the largest glaciers outside the polar region. It lies in the north of Passu 7,500 meter above sea level, located geographically at 36o 30`N to 36o 40`N and 74o 22` 33“E to 74o 52` 30“E. It feeds River Hunza in northern Pakistan which flows west to east. River Hunza is joined by the Gilgit and the Naltar Rivers before it flows into the Indus River. It was observed that the ice covered and ice free areas in the year 1992 was 98 km2 and 25 km2 respectively, whereas in the year 2000, the ice covered area reduced to 81km2 , consequently increasing the ice free area to 42km2.
Biafo Glacier is the third largest glacier in the Karakoram and the fourth largest in Asia (Hewitt, K, 1989). The Biafo Glacier is located on the south-facing slopes of the Karakoram Range in the Baltistan area of Ladakh. It lies in the center of Shigar River Basin located geographically at 35o 19`N to 36o 07`N and 74o 53`E to 76o 75`E. The main stream originating from this glacier is Barldu River flows into the Shigar River which in turn is a tributary of the Indus River. The analysis indicates that snow and ice cover and free area in 1992 was 92.807 km2 and 20.916 km2 respectively, and in 2000 the ice cover area reduced to 86.250 km2.
Floods Due to Glaciers Melting:
Flash floods are becoming more common in the Hindu Kush Himalayas. Local communities are most at risk – but glacier melt also affects people who live far away from the mountains.
More than a century ago, a catastrophe struck Barikan Kot. This mountain village was flooded by a sudden outburst of water from the Hinarchi glacier. The reason was the bursting of an ice wall which had held back a lake of meltwater that had formed on the glacier. About 100 families lost their homes and livelihoods as rocks, earth and debris were swept over the village and its orchards and fertile land.
In the past, this kind of flash flood occurred rarely. That has changed. The Bagrote valley in the Karakoram mountain range in northern Pakistan now suffers several of them every year. Global warming is affecting glaciers all over the world, and the Hindu Kush Himalaya is no exception. Especially in the summer months, melting ice leads to new glacial lakes which, in turn, can cause flash floods.
Temperatures rise in future:
The change in the global surface temperature between 1850 and the end of the 21st Century is likely to exceed 1.5 °C, most simulations suggest.
The WMO says that if the current warming trend continues, temperatures could raise 3-5 °C by the end of this century.
Temperature rises of 2 °C had long been regarded as the gateway to dangerous warming. More recently, scientists and policymakers have argued that An Intergovernmental Panel on Climate Change (IPCC) report in 2018 suggested that keeping to the 1.5 °C target would require in all aspects of society.
The UN is leading a political effort to stabilize greenhouse-gas emissions. China emits more CO2 than any other country. It is followed by the US and the European Union member states, although emissions per person are much greater there.
But even if we now cut greenhouse-gas emissions dramatically, scientists say the effects will continue. Large bodies of water and ice can take hundreds of years to respond to changes in temperature. And it takes CO2 decades to be removed from the atmosphere.
Glacier Mass Change:
- Glaciologists assess the health of glaciers by studying their mass balance, length and area.
- Glaciers gain mass through snowfall and lose mass through melting and sublimation.
- When more mass is lost than gained, the mass balance of a glacier is negative. Glaciers mass slowly decreasing with the increase in temperature of Himalayan. The number of glaciers is increasing but their volume is decreasing after melting. Over time the glaciers of the Hindu Kush Himalayas will decrease in size.
- No longer will contribute to the region’s water supply each year in future.
- Shifts in the location and intensity of snow and rain could also affect the rate of glacial retreat.
Recent Conflicting Reports about Recession of Himalayan Glaciers:
- In 2005, Hewitt reported widespread evidence of glacier expansion in the late 1990s in the Central Karakoram, in contrast to a worldwide decline of mountain glaciers.
- Based on surveys between 1997 and 2002, he reported that some of the large Karakoram glaciers – 40 to 70 km in length – exhibited 5 to 15 m of thickening over substantial ablation zone areas, locally more than 20 m.
- These conflicting findings make the impact of climate change on Karakoram glaciers and Indus River flows very uncertain.
Authors: Anum Basheer1, Wajeeh Ur Rehman1, Muhammad Sajjad1, Amir Baig1 and Sajid Hussain1 1 Department of Agronomy, University of Agriculture, Faisalabad.