Himalayan glaciers melting far faster this century: Study - Pragnya IAS Academy - News Analysis.

Himalayan glaciers melting far faster this century: Study.

• The accelerated melting appears to be swelling rivers during warm seasons.
• The new analysis, spanning 40 years of satellite observations across India, China, Nepal and Bhutan.

Himalayan glaciers have been melting twice as fast since the start of this century, underscoring the threat the climate crisis poses to water supplies for hundreds of millions of people across Asia, according to a study published on Wednesday.
Scientists have long been trying to establish how quickly rising global temperatures caused by the burning of coal, oil and gas are eating away at the region's icebound landscapes, sometimes referred to as Earth's third pole.
The new analysis, spanning 40 years of satellite observations across India, China, Nepal and Bhutan, showed glaciers have been losing the equivalent of more than a vertical foot-and-a-half of ice each year since 2000. That represents double the rate between 1975 and 2000.
"This is the clearest picture yet of how fast Himalayan glaciers are melting over this time interval, and why," lead author Joshua Maurer, a PhD candidate at Columbia University's Lamont-Doherty Earth Observatory, said in a statement.
Although the study, published in Science Advances, did not attempt to ascertain precisely how much ice had melted, Maurer said the glaciers may have lost as much as a quarter of their mass over the last 40 years.
The accelerated melting appears to be swelling rivers during warm seasons, but scientists are concerned about the long-term impact on irrigation, hydropower and drinking water supplies that support some 800 million people.
Joseph Shea, a glacial geographer at the University of Northern British Columbia, who was not involved in the study, said the findings demonstrated that even glaciers in the world's highest mountains were being affected by higher temperatures.
"In the long term, this will lead to changes in the timing and magnitude of streamflow in a heavily populated region," Shea said. (Source: Livemint)


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Himalayan glaciers melting far faster this century: Study

Melting of Arctic ice impacts weather in India - Pragnya IAS Academy - News Analysis.

Melting of Arctic ice impacts weather in India.

• Rising temperature is causing sea-ice to melt, impacting ocean current linked to extreme weather events

• The study was conducted by Germany-based Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research

Months ahead of a major global expedition to explore the Arctic, researchers found that rising temperatures in the region is causing the sea-ice to melt faster than expected, impacting a major ocean current linked to extreme weather events.

The study was conducted by Germany-based Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, whose researchers would spearhead MOSAiC, one of the biggest Arctic Research Expeditions set for sail this year, with participation from more than 17 countries.

The Arctic Ocean is surrounded by some marginal seas which constantly produce new ice in winters. The ice floes are transported from the Siberian part of the Arctic Ocean, across the Central Arctic and into the 600 km wide Fram Strait--the only gateway to the Arctic Ocean from the Atlantic Ocean.

This journey is enabled by a wind-driven current called the Transpolar Drift, one of the two major currents in the Arctic Ocean. The journey takes over 2-3 years, during which the ice floats increase in thickness (9.8-13.1 feet).

According to the latest research published in Scientific Reports, only 20% of the sea-ice that forms in the shallow Russian marginal seas of the Arctic Ocean is actually reaching the Central Arctic, where it joins the Transpolar Drift. The remaining 80% of the young ice melts before it reaches Central Arctic and is not thick anymore.

Till the 1990s, half of the ice from Russia’s shelf seas used to make this trans-arctic journey, said the researchers who monitored the movement of the sea-ice with the aid of satellite data for over two decades.

“The melting of sea ice in the marginal seas is now so rapid and widespread that we are seeing a lasting reduction in the amount of new ice for the Transpolar Drift," said the first author, Dr Thomas Krumpen, a sea-ice physicist at AWI. “On average, the ice is 30% thinner than it was 15 years ago. What we’re witnessing is a major transport current faltering, which is bringing the world one major step closer to a sea-ice-free summer in the Arctic."

The faltering of Transpolar Drift could lead to weather implications across countries, including India, as it is a major factor in Arctic Oscillations, a dominant climate pattern that influences weather throughout the Northern Hemisphere.

According to Indian scientists, it could have a bearing on the south-west monsoon.

“If there is less ice in the Arctic, the polar vortex instead of concentrating in the Arctic, will wobble and come up to mid-latitude. If it comes up to mid-latitude, then it will affect weather in India. We could see a rise in intensity and frequency of western disturbances," said Dr Ravichandran M, Director, National Centre for Polar and Ocean Research, Goa.

German researchers highlight that the weakening of Transpolar Drift is also reducing the natural transport of nutrients, algae, sediments and minerals from the Arctic to the Fram Straits, causing lasting changes in the biogeochemical cycles and ecological processes of the central Arctic Ocean in future.

Instead of Siberian minerals, we are now finding more remains of dead algae and microorganisms in our sediment traps," says co-author Eva-Maria Nöthig.

The changes in the biodiversity in the Arctic have been one of the focus areas of Indian researchers as well, who are trying to understand how the ecosystem is changing over the years due to global warming. “Arctic is more important to us. Sea ice is declining much faster in Arctic than Antarctic or the South Pole," said Dr Ravichandran. (Source: Livemint)

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Melting of Arctic ice impacts weather in India.

Why India needs to worry about melting glaciers - Pragnya IAS Academy - News Analysis.

Why India needs to worry about melting glaciers.

• If adequate steps are not taken to limit global warming, two-thirds of glaciers in the Hindu Kush Himalayas could melt by 2100
• Hindu Kush is Asia’s water tower, providing a vital regional lifeline to over two billion people through 10 main river
A new study has said that if adequate steps are not taken to limit global warming, two-thirds of glaciers in the Hindu Kush Himalayas could melt by 2100, and large increases in run-off could lead to flooding of major rivers. Mint analyses the major findings of the study.
What are the main findings of the study?
The Hindu Kush Himalayan region is of critical importance, given that it holds the largest ice mass after the North and South Poles, and has been on a constant warming trend since the 1970s. The study warns that if global efforts to limit global warming to below 2°C above pre-industrial levels fail, it could lead to the melting of two-thirds of the region’s glaciers by 2100. This could be catastrophic, given that there are 8,790 glacial lakes in the region, of which 203 could lead to floods from glacial lake outbursts. On an average, 76 events of natural hazard occur every year in the Hindu Kush, with China accounting for 25 and India 18.
How could warming in the Himalayas destabilize rivers?
Hindu Kush is Asia’s water tower, providing a vital regional lifeline to over two billion people through 10 main rivers that originate from the glaciers. Increasing glacial melts could destabilize these rivers by changing their stream flow. The Indus could witness more stream flow due to high glacial melt till 2050, after which the flow would start reducing due to decreasing glacial melt. The Ganga and the Brahmaputra, which are mainly monsoon-fed rivers, will also see variations, as pre-monsoon flows may decline. This will hamper agriculture that accounts for the largest share of water usage.
Are rising pollution levels contributing to the crisis?
The Indo-Gangetic Plain, an extremely polluted region, has amplified the effects of greenhouse gases. Deposits of black carbon and dust have sped up the melting of Hindu Kush glaciers.

What could be the impact on monsoons?
The Hindu Kush range exerts a significant influence on seasonal shifts in the monsoon circulation and the distribution of rainfall over Asia in summer. The south-west monsoon accounts for 70% of the annual rainfall in India. Projections for the region indicate a likely increase in summer rainfall by 4-12% in the near term and 4-25% in the long term. Changing monsoon patterns, including increased severity and frequency of storms, could lead to mountain hazards that may destroy critical infrastructure.
Could there be a threat of forced environmental migration?
Researchers say that forced migration could occur with an increase in the incidence and magnitude of extreme events such as floods. There could be large-scale demographic movements. The annual rate of increase in migration in the countries of the Hindu Kush Himalayas has been disturbingly high and the number of internally displaced people is also expected to rise. The region will have many more people in vulnerable urban areas in the next 20 years, says the study.


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Why India needs to worry about melting glaciers.