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?
Answer & explanation
Answer: (d) Reducing the global warming
Both are proposed geoengineering methods of 'solar radiation modification', meant to cool the planet. Stratospheric sulphate aerosols would reflect sunlight back to space, copying the cooling seen after big volcanic eruptions; thinning heat-trapping cirrus clouds would let more of the Earth's heat escape.
- ✓ (d) The IPCC lists stratospheric aerosol injection and cirrus cloud thinning among the most-studied SRM methods, whose aim is to reduce warming.
- ✗ (a) Artificial rain uses cloud seeding with silver iodide or salt in rain-bearing clouds, not stratospheric sulphate.
- ✗ (b) These methods target the planet's overall heat budget; they are not cyclone-suppression tools.
Remember · Solar radiation modification (geoengineering to cut warming): stratospheric aerosol injection, marine cloud brightening, cirrus cloud thinning, surface albedo change. Carbon dioxide removal is the other branch.
📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 11 (practise this chapter)
Sources
- IPCC Special Report on Global Warming of 1.5 °C, Glossary ↗ “Solar radiation modification refers to the intentional modification of the Earth’s shortwave radiative budget with the aim of reducing warming. Artificial injection of stratospheric aerosols , marine cloud brightening and land surface albedo modification are examples of proposed SRM methods.”
- IPCC Special Report on Global Warming of 1.5 °C, Chapter 4 ↗ “Table 4.7 Overview of the main characteristics of the most-studied SRM methods SRM indicator Stratospheric Aerosol injection (SAI) Marine Cloud Brightening (MCB) Cirrus Cloud Thinning (CCT)”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 11 “Volcanic eruption throws up lots of aerosols into the atmosphere. These aerosols remain in the atmosphere for a considerable period of time reducing the sun's radiation reaching the Earth's surface.”
Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·