Be Mains Ready

Approach

• Explain what are dust storms.
• List the causes of dust storms.
• State the measures to be taken to prevent dust storms.
• Conclude by providing solutions.

Introduction

A dust storm or sandstorm is a meteorological phenomenon, which refers to the erosion, transport and deposition of dust and soil particles in the atmosphere by strong wind currents. They are a combination of sand, dust and wind. The fluctuation in their intensity, magnitude or interaction with each other makes them unpredictable and dangerous.

Rapid desertification, unprecedented heat wave conditions, greater number of western disturbances, and low pressure winds have combined to trigger the massive dust storms across India.

Body

Causes of Dust Storms

• Anthropogenic reasons: The Global Assessment of Sand and Dust Storms reports concluded that 25% of global dust is anthropogenic emission.
  
  • Unsustainable land and water use, deforestation, overgrazing, depletion of water sources and industrial activities have triggered sand and dust storms in the country.

Climate Change and Associated Causes

• Increased heating of atmosphere- The weakening temperature gradient is causing the jet streams to meander rather than take a straight course which, in turn, affects the seasonality and movement of the western disturbances.
  
  • Additionally, steep increases in temperatures in the Western Himalayan region and the Tibetan Plateau have been linked to a further destabilisation of climatic patterns in the region.
• Longer durations of Western disturbances- The western disturbances are not only active over the Indian region for a longer period of time, but the jetstreams over the region have also strengthened.
  
  • The high levels of emissions in the Indo-Gangetic basin increase the temperature of the atmosphere by absorbing solar radiation.
  • This increase in atmospheric temperatures changes the vertical temperature gradient in the atmosphere and triggers a strong downward wind movement from the upper levels of the atmosphere, up to 12 km high.
  • These downward drafts join the jetstreams as they enter the subcontinent and strengthens them. This has resulted in the recent spate of storms.
• Diverging Jet streams- The jetstreams carried by western disturbances are not uniform in velocity across the band. The jetstream core seems to have undergone divergence in the upper levels which, in turn, causes a convergence of air lower down in the atmosphere. This is one of the contributing factors towards the intensity of the storms

Measures That Can Be Taken

• Anthropogenic source mitigation: Source mitigation may be the only way to reduce dust emission. Appropriate techniques that already exist at national and regional levels as part of sustainable land management need to be identified and scaled up, taking into account the synergies among the Rio Conventions and related mechanisms and initiatives.
  
  • Lack of vegetative barrier is making dust storms more intense. India needs to take up massive afforestation.
  • All dust generating activities—from digging of roads to construction need strict regulation.
• Improving weather forecasting and monitoring infrastructure: Early warning is a critical part in the dust storm impact mitigation.
  
  • It should enhance the ability of countries to deliver timely, quality dust storm forecasts, observations, information and knowledge to users.
  • Doppler radar can be used to detect dust levels close to the surface and horizontal wind velocities.
• Increasing preparedness and resilience: Dust storm should be fully integrated into multi-hazard management plans for disaster risk at all levels and across all sectors.
  
  • The dust storm management plans need to include coordinated emergency response measures and strategies across sectors based on systematic impact/vulnerability/risk mapping/assessment.

Conclusion

• Dust storms have socio-economic impacts on human health, agriculture, industry, transportation, water & air quality. Increased number of storms lasting later into the season also affect the progress of the monsoon as it reduces the strength of onrushing monsoonal winds which enter the subcontinent in the beginning of June.
• Although government has taken some steps in this direction like- integration of component of dust in the National Centre for Medium Range Weather Forecasting, improvements in satellite and 3-D imaging and adoption of NowCast models that have a constant eye on evolving weather from space, and can pick up signs of the storms around three hours in advance, more needs to be done.
• A massive wall of vegetation like the Great Green Wall that has been developed by China along the Mangolian drylands or a similar Great Green Wall in Africa's Sahel region, at the southern edge of the Sahara desert can be built by India to prevent land and wind erosion and to mitigate the impacts of dust storms.