CONTEXT

• Global warming & atmospheric sulphur: With rising concerns about global warming and reduction of human-made (anthropogenic) sulphur emissions, understanding natural sulphur sources has become crucial.
• Air quality policies: Many countries, including India, are implementing stricter regulations to reduce emissions of carbon, sulphur, and nitrogen oxides from industrial and vehicular sources.

CONCEPT

• What is DMS (Dimethyl Sulphide)?
  • A natural sulphur-bearing compound produced by phytoplankton in oceans.
  • Responsible for ~40% of atmospheric sulphur.
  • Plays a critical role in cloud formation by transforming into aerosols in the atmosphere.
• Climate interaction:
  • Aerosols formed from DMS help in reflecting solar radiation, thereby cooling the Earth.
  • Increased cloud cover can partly offset warming impacts, though not completely.
• Current understanding challenge:
  • Existing climate models differ on DMS projections—some show increase, others show decrease.
  • Need for accurate models to predict DMS behavior under future climate scenarios.

CURRENT 

(IITM Pune + European scientists, 2024)

• Sea surface changes:
  • Sea surface temperatures and wind speeds are projected to rise.
  • Despite a predicted decrease in DMS in ocean water, more DMS will enter the atmosphere.
• Key study features:
  • Used machine learning models trained on global ocean-biological data.
  • Simulated DMS emissions from 1850–2100 under 8 climate models.
• Contradicting assumptions:
  • Contrary to previous climate projections, atmospheric DMS is likely to rise.
  • Indicates DMS may become a dominant natural sulphur source as human emissions fall.

IMPLICATIONS FOR INDIA & POLICY

• Important for climate forecasting and mitigation strategies.
• Enhances understanding of natural cooling feedback mechanisms.
• May influence future environmental and marine conservation policies.