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Aerosol formation brightening clouds

Aerosol formation brightening clouds

Tag: GS 3 || Environment || Climate Change|| Tackling Climate Change

Why In News?

  • Small aerosol particles help in “brightening” of clouds, enabling them to alter Earth’s radiative balance and ultimately its climate, according to a study.

What is Aerosol?

  • An aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas.
  • Aerosols can be natural or anthropogenic.
  • Examples of natural aerosols are fog, dust, forest exudates and geyser steam.
  • Examples of anthropogenic aerosols are haze, particulate air pollutants and smoke.
  • These fine particles scatter sunlight and stop some of it from reaching the earth’s surface. Their scattering of sunlight can reduce visibility (haze) and redden sunrises and sunsets.
  • Aerosols are short-lived, unlike greenhouse gases that persist and thereby accumulate in the atmosphere for longer period.

Formation in atmosphere

  • When deep, convective clouds in the tropics(tropics are regions of the Earth that lie roughly in the middle of the globe) carry gases high into the atmosphere, they form small aerosol particles in a process called gas-to-particle conversion.
  • As they condense, they grow big enough to brighten lower-level cloud in the lower troposphere.
  • This gas-to-particle conversion brightens clouds in the tropics over both the Pacific and Atlantic Oceans.

Why are they significant?

  • These brighter clouds reflect more energy from the sun back to space.
  • Further, this formation of new particle covers about 40 per cent of the Earth’s surface, which means some of the current climate models underestimate the cooling impact of some clouds.
  • Understanding how these particles form and contribute to cloud properties in the tropics will help us better represent clouds in climate models and improve those models.
  • The study showed that in remote places with cleaner air, the effect of aerosol particle formation on clouds was found to be much larger.

Aerosol impact on Indian monsoon

  • When scientist introduced the effect of aerosols on climate, the record collected showed that the India’s monsoon rainfall was decreasing over the last 50 years due to aerosols.
  • The greenhouse gases pushing in one direction and is warming the ocean that results more rain whereas on the other side the aerosols are pushing in another direction for cooler oceans and results lesser rain.

 Cloud Whitening

 What is Stratospheric Aerosol Injection (SAI)?

  • This geo-engineering technique known as stratospheric aerosol injection (SAI)could limit rising temperatures that are causing climate change.

Possible side effects:

  • Tropospheric Ozone depletion.
  • Whitening of the sky.
  • Tropopause warming and the humidification of the stratosphere.
  • Involves Health effects.
  • Stratospheric temperature rise and circulation change.

Additional Info

https://www.thehindu.com/sci-tech/energy-and-environment/lsquoIncreasing-reflectivity-of-clouds-an-option-to-cool-the-earth/article16205120.ece

 Mains  Question

 What is the role of aerosols in maintaining Earth temperature?