ICIMOD report rings warning bells for rivers of East and Northeast India

ICIMOD report rings warning bells for rivers of East and Northeast India

Subject: Geography

Section: Physical geography (Climatology)

Context:

• Rivers in eastern and northeastern India including the Brahmaputra, Ganga and Teesta will see a rapid increase in stream flow followed by water scarcity, a new report released by the International Centre for Integrated Mountain Development (ICIMOD) on June 20, 2023, warned.

Report details:

• The report — Water, ice, society, and ecosystems in the Hindu Kush Himalaya — pointed out that glaciers in the HKH region can lose up to 80 per cent of their current volume by the end of the century (with) Himalayan glaciers disappearing 65 percent faster in the 2010s than in previous decade.
• The glaciers lost a mass of 0.28 metres of water equivalent per year (m w.e.)  between 2010 and 2019 compared to 0.17 (m w.e.) per year between 2000 and 2009.
• The Karakoram range, which was known to be stable, has also started showing a decline in glacier mass, losing 0.09 m w.e. per year during 2010-2019.
• Floods and landslides are projected to increase over the coming decades.
• India-specific findings:
  • The Union Ministry of Earth Sciences also informed that glaciers feeding the Ganga and the Brahmaputra river basins were melting at a fast rate.
    • The mean retreat rate of the Hindu Kush Himalayan glaciers was 14.9-15.1 metres per annum, which varied from 12.7-13.2 metres per annum in the Indus, 15.5-14.4 metres per annum in the Ganga and 20.2-19.7 metres per annum in the Brahmaputra river basins.
  • The Eastern Ganga region (EGR) is already facing Erratic and extreme rainfall, extreme floods and landslides, droughts, low flows, and scorching wet bulb heat.
  • Eastern Himalayas, also called lesser Himalayas, have fewer glaciers compared to their Western counterparts.
    • Hence, rivers in the region get less contribution from such glaciers; and are less likely to be affected overall.
• Loss of permafrost:
  • The report highlighted the limited available information on permafrost — ground that remains at or below 0°C for at least two consecutive years — in the Hindu Kush region.
  • Studies have estimated that western Himalaya lost 8,340 square km of permafrost area between 2002 and 2004 and 2018 and 2020, and about 965 square km of area disappeared in Uttarakhand Himalaya between 1970 and 2000 and 2001 and 2017.
  • The loss of permafrost could lead to infrastructure damage, costing the world several billion dollars.

Hindukush-Himalaya Region:

• Stretching over 3500 kilometres and across eight countries – Afghanistan, Bangladesh, Bhutan, China, India, Nepal, Myanmar and Pakistan – the Hindu Kush Himalaya is arguably the world’s most important ‘water tower’, being the source of ten of Asia’s largest rivers as well as the largest volume of ice and snow outside of the Arctic and Antarctica.
• Together these rivers support the drinking water, irrigation, energy, industry and sanitation needs of 1.3 billion people living in the mountains and downstream.

Biodiversity of HKH region:

• The mountain ecosystems of the Hindu Kush Himalaya (HKH) are diverse with one of the highest diversity of flora and fauna providing varied ecosystem services to one fourth of humanity. With four out of 36 global biodiversity hotspots the HKH is a cradle for 35,000+ species of plants and 200+ species of animals.
• At least 353 new species—242 plants, 16 amphibians, 16 reptiles, 14 fish, two birds, and two mammals, and at least 61 invertebrates—have been discovered in the Eastern Himalayas between 1998 and 2008, equating to an average of 35 new species finds every year.
• The Hindu Kush Himalaya (HKH) region is of global importance due to its unique biodiversity and is home to 4 of 34 global biodiversity hotspots, 6 UNESCO natural World Heritage sites, 30 Ramsar sites, 330 Important Bird Areas (IBAs) and 53 Important Plant Areas (IPAs).
• In total, there are 60 ecoregion types (6 per cent of the world total), of which 30 are critical ecoregions.
• HKH countries have established roughly 488 protected areas in the region with varying degrees of protection and status, covering 39 per cent of HKH terrestrial land.

Significance of Hindukush- Himalaya region (HKH):

• The biodiversity of the region — 40 per cent of which is under protected areas — is dependent on the cryosphere as it is an important source of water for maintaining ecosystem health, supporting biological diversity, and providing ecosystem services.
• Glaciers occupy an area of approximately 73,173 square kilometres (km2) in the HKH.
• The average temperature in the region has increased by 0.28°C per decade between 1951 and 2020.
• The HKH region harbours the highest mountain ranges in the world. It also contains the largest volume of ice on earth outside of the polar areas and is called “Asia’s water tower”.
• The region is undergoing “unprecedented and largely irreversible” changes triggered by global warming.
• Ice and snow in the Hindu Kush Himalaya are an important source of water for 12 rivers that flow through 16 countries in Asia, providing fresh water and other vital ecosystem services to 240 million people in the mountains and a further 1.65 billion downstream.