Question 57 from UPSC CSE 2019 - Environment

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 the stratosphere?

IASCODEX · Accepted Answer

Correct Option: D. Reducing global warming

Strategy: Identify the unique keywords 'cirrus cloud thinning' and 'sulphate aerosol injection into the stratosphere.' Link these terms to geoengineering methods aimed at mitigating global warming by altering Earth's radiative balance. Select the option that reflects this environmental intervention, excluding choices related to rain, cyclones, or solar wind.

Key Info: ### Geoengineering Strategies

Cirrus cloud thinning and stratospheric aerosol injection are two proposed geoengineering strategies aimed at climate intervention.

- Cirrus cloud thinning involves deliberately modifying high-altitude, ice-crystal cirrus clouds so they allow more infrared (heat) radiation to escape from Earth. Cirrus clouds tend to trap outgoing longwave radiation, contributing to warming. Thinning these clouds can help cool the planet.

- Stratospheric aerosol injection (SAI) is the process of introducing reflective sulfate aerosols (typically sulfur dioxide, SO2) into the stratosphere. These particles reflect a portion of incoming solar radiation back into space, thereby reducing global surface temperatures. This method is inspired by natural cooling events following major volcanic eruptions (such as Mount Pinatubo, 1991).

- Both techniques are classified as Solar Radiation Management (SRM) methods within the broader field of geoengineering (climate engineering). They are not intended for inducing rainfall, mitigating cyclones, or protecting against solar wind.

- While promising in theory for reducing the adverse impacts of global warming, these methods are controversial due to their uncertain side-effects, regional climatic imbalances, and ethical considerations. There are currently no large-scale deployments, only modeling and small-scale research.

- Such geoengineering approaches do not target weather events like artificial rain (cloud seeding), cyclone suppression, or solar wind mitigation.

IASCODEX · Answer

Option A: Creating artificial rains in some regions

IASCODEX · Answer

Option B: Reducing the frequency and intensity of tropical cyclones

IASCODEX · Answer

Option C: Reducing the adverse effects of solar wind on the Earth