COP27 & Glacier Melt
By Dhurjati Mukherjee
The COP27 has just begun in the Egyptian coastal city of Sharm el-Sheikh and the planet is sending a distress signal. “Sea level rise, glacier melt, torrential rains, heat waves — and the deadly disasters they cause — have all accelerated,”warns the World Meteorological Organisation in a report. While the world will debate as usual, reports have clearly indicated that it is still nowhere near the scale and pace of emission reductions required to put us on track toward a 1.5 degrees Celsius world.In fact, there has been a warning that national governments need to strengthen their climate action plans now and implement these in the next eight years, which means that the onus would now be on emerging economies including India.
Dealing with just one implication of global warming, it is in fitness of things to refer to an article way back in 2013 in Nature where scientists cautioned that rising temperatures in the Himalayas raise the threat of glacial lake outburst, which is even more relevant today. Of the 8800 glacial lakes in the Himalayas, over 200 have been classified as dangerous. Himalayan nations were urged to build an international network to monitor risks such as those from glacial lakes and give early warning of hazards. Will the issue get the focus it deserves or get lost in new pledges?
According to available data, the Himalayan river basins cover an area of 2.75 million square kilometers and have the largest irrigated area of 577,000 square kilometers, and the world’s largest installed hydropower capacity of 26,432 MW. The melting glaciers fulfill the water requirements of over a billion people of the region. Obviously, these people will be affected when much of the glacier ice mass melts and gradually stops supplying water to inland rivers. While Ganga and Brahmaputra basins in India get a big chunk of their water from monsoons, the situation is different for the Indus river, which is largely dependent on the glaciers. However, changing rainfall patterns and rising global temperature will affect the Ganga and Brahmaputra basins as well
As is evident, majority of glaciers in the Himalayan region are melting due to rising temperatures. Studies conducted by Geological Survey of India, Wadia Institute of Himalayan Geology National Centre for Polar and Ocean Research and the Indian Institute of Science have observed accelerated heterogeneous mass loss in Himalayan glaciers. According to the Ministry of Earth Science, the mean rate of Hind Kush Himalayan glaciers is around 15 metres per year which is 12.7-13.2 metres in Indus, 15.5-14.4 metres in Ganges and 20.2-19.7 in Brahmaputra river basins.
The landslides that have occurred in recent years have been triggered by a plethora of natural and man-made factors such as heavy rainfall, earthquake, active geological features, deforestation, large-scale land use changes among others. It needs to be mentioned here that our investment in pro-active scientific approaches — natural hazard surveillance or flood forecasting — is not sufficient and technologically sound. In the absence of science policy-based instruments, the destruction has been grave over the years.
However, in the first detailed inventory of glaciers at the Alaknanda river basin, which contributed the maximum water to river Ganga, scientists from IISc and IITs discovered a reduction of 59 sq km in the glacier area over a period of almost 50 years, between 1968 and 2020. This meant that 8 percent of the total area of glaciers decreased. Scientists said regional climate change was a big reason behind the development. This study of the river basin, which took over two years to complete, was published in the Geocarto International journal by Taylor & Francis. The average retreat rate of glaciers in the basin was 11.75 m per annum.
The analysis of climatic parameters in the basin suggested substantial evidence of deglaciation due to global warming, especially since the winter temperature increased by 0.03 celsius per year between 1968 and 2020. The team of scientists studied almost all satellite imagery since 1968 meticulously and found that though the area of the glaciers reduced in the river basin, the number of glaciers increased from 98 to 116.
Scientists said the increase in numbers was a cause for concern. Small portions of the glaciers were melting in a way that they would not contribute water to the river and hence, there would be a “cascading effect” on the water security of the people living downstream, they observed.
“They are melting faster and forming new water bodies such as lakes near the glacier. If the glaciers melt faster in the future, these water bodies will get added water and may overflow, causing destruction,” experts pointed out.
The seasonal runoff from Himalayan glaciers provides different water services to about 800 million people for the purposes including irrigation, hydropower and drinking water. As the glaciers melt unconventionally, it will eventually result in water shortages. The greater runoff causes the rivers to flood. Glacier melting, in some measure, affects the snowfall. A regular reduction in usual winter snowfall leads to water shortage.
Thus, the melting of these glaciers is undoubtedly a major cause of concern as it is expected to have a massive impact on the water supply for the rivers. Experts believe that continued melting will lead to change in glacier basin hydrology, downstream water budget and impact on hydropower plants due to variation in discharge, flash flood and sedimentation.
Excessive melting doesn’t help water to mix with rainfall and groundwater, which is used for crop irrigation and future supply during drought. The ratio of run-off to rainfall determines both groundwater recharge and groundwater depletion. Increased glacial melting would disturb this even distribution sustaining a large population until now. It has been amply evident that the increased melting of Himalayan glaciers has been causing flooding disasters and this is expected to continue in the next few years. What would happen after that is the Ganga and the Indus flowing with radically reduced pace may result in acute water stress, mass migration, and unseen conflicts.
A study of IIT Indore last year found that the total river runoff, glacier melt, and seasonality of flow are set to increase until the 2050s, and then decrease, with some exceptions. Researchers have called for greater focus on the problems and to assess the current status and potential future changes of rivers for sustainable water resource management for agriculture, hydropower, drinking, sanitation, and hazard situations.
Climate change and global warming are indeed dangerous phenomena, and its consequences are severe for humans, affecting them in all possible ways. Even water, which is the basis for human survival, has been affected in various ways due to the ravages of nature and glacial melt is a key reason. There is thus an immediate need to ensure that warming is controlled by checking emissions of greenhouse gases to counter the disastrous effects of glacier melting. Experts and organisations working in the field should come out with an action plan to control such melting in the coming years.— INFA
(The author is Sr. Consultant & Guest Faculty of Bharatiya Vidya Bhavan, Kolkata; an avowed writer and speaker on issues such as social and economic development, environment, Gandhian thought and peace studies.)