UPSC Prelims 2019 Question:

In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?

Explanation:

• Stratospheric Aerosol Injection (SAI) is a geoengineering technique to inject sulphate aerosol into the stratosphere to control global warming. Global warming can be controlled by either controlling carbon emissions or by controlling solar radiation from reaching the earth’s surface.
  
  
• SAI technique proposed spraying large quantities of aerosols (Sulphate particles) into the Stratosphere (upper layer of the Atmosphere) to act as a reflective barrier against sunlight. These reflective particles block and reflect the sun’s rays back to space, which reduces heat absorbed by the earth. Thus, it limits rising temperatures that are causing global warming and climate change.
  
  

Therefore, option (4) is the correct answer.

Subject: Environment | Climate Change