Dust from the Sahara is being blown thousands of miles and landing on mountains in the Himalayas – hastening the melting of the snow caps, study finds
- NASA-funded study used satellite images and looked at dust levels in Himalayas
- Found dust from deserts including the Sahara are reaching the snow caps
- The dark particles soak up more sunlight and heat than the white snow
- Increases warming and increases melting by dampening the albedo effect
Dust from some of the world’s largest deserts is contributing to the rapid melt of the Himalayan snow caps, scientists have found.
The particles reach the peaks after travelling thousands of miles from the Indian Thar Desert, the plains of Saudi Arabia and the Sahara Desert.
After being carried around the world on vast air currents, the particles settle on the Asian mountain range and darken the otherwise pristine snow.
This dampens the phenomenon known as the ‘albedo effect’ where light-coloured surfaces reflect more heat, helping keep areas cool.
As a result of the dust, the darker snow is absorbing more heat and therefore melting quicker. It is thought this could explain the rapidly melting snow in the Himalayas.
Dust is reaching the snow capped mountains of the Himalayas (pictured) and speeding up melting, NASA funded research reveals
A NASA-funded international team of researchers scoured some of the most detailed satellite images ever taken of the Himalayas and recorded levels of minute atmospheric aerosol particles, elevation and the amount of dust present on snow.
It revealed the amount of dust being blown onto the snow caps was interfering with the albedo effect.
This is a simple physical phenomenon where dark objects absorb more wavelengths of light than light coloured objects.
Light colours, and specifically white, bounces most of the energy from the Sun back into space, keeping temperatures cool.
But the dark dust particles do the opposite and soak up more thermal energy and reflect less, causing warming.
Desert dust is naturally occurring but its prevalence in the Himalayas has been influenced by human activities, the researchers believe.
For example, increasing temperatures caused by climate change have altered atmospheric circulation, enhancing winds that carry dust thousands of miles on ‘aerosol layers’.
Intensive farming and increasing development have also reduced vegetation, causing more dust to be created that would otherwise remain trapped to the land.
The increased presence of dust atop mountains is a leading contributor to the unprecedented rate of snow loss in the Himalayas, the researchers say.
Co-lead author Dr Chandan Sarangi, of the Indian Institute of Technology Madras, said: ‘The snow in the western Himalayas is receding rapidly.
‘We need to understand why this is happening – and we need to understand the implications. We’ve shown dust can be a big contributor to the accelerated snowmelt.’
Twice as many mountaineers successfully climb Mount Everest now than three decades ago — but the death rate remains at around 1 per cent, a study has found.
Reaching some 29,030 feet above sea level, the summit of Everest in the Himalayas attracts around 500 climbers wanting to scale the world’s tallest peak each spring.
The last thirty years have seen a increase in the number of people making the ascent — increasingly crowding the narrow route through the ‘death zone’ near the summit.
This is the altitude above around 26,247 feet at which the oxygen pressure falls to the extent that it is unable to sustain human life for prolonged periods of time.
As the climate warms and snow lines move higher the role of dust is expected to become even more pronounced in the Himalayas, the scientists predict.
The Himalayan mountain range is vast and home to the world’s tallest mountains, including Everest and K2.
The albedo effect at high elevations, above 4,500 metres (14,764ft), is crucial to life for millions of people who rely on snowmelt for their drinking water.
Darker, dirtier snow melts faster and changes the timing and amount of freshwater created.
This has knock-on implications for agriculture and other aspects of high-altitude life.
The study assessed only the western Himalayas, but the researchers believe the findings can be applied to other mountain ranges.
Dr Yun Qian, an atmospheric scientist at the US Department of Energy’s Pacific Northwest National Laboratory, said: ‘These including the Rockies, Sierras and Cascades in North America and several mountain chains in Asia, such as the Caucuses and Urals.’
‘It turns out dust blowing hundreds of miles from parts of Africa and Asia and landing at very high elevations has a broad impact on the snow cycle in a region that is home to one of the largest masses of snow and ice on Earth.’
The study is published in Nature Climate Change.
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