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Study on Stratospheric Aerosol Intervention


A recent study published in the journal Nature Food highlights the potential consequences of a geoengineering technique, stratospheric aerosol intervention (SAI), on global food production.


GS III: Environment and Ecology

Dimensions of the Article:

  1. Key Findings of the Study on Stratospheric Aerosol Intervention (SAI)
  2. Stratospheric Aerosol Intervention (SAI)
  3. Geoengineering Techniques

Key Findings of the Study on Stratospheric Aerosol Intervention (SAI)

Introduction to SAI

  • SAI is considered a backup plan to combat climate change if traditional mitigation methods fail.
  • It replicates volcanic eruptions by releasing sulphur dioxide into the stratosphere, forming reflective aerosol particles.

Effect on Global Temperature

  • The 2001 Mount Pinatubo eruption injected 15 million tonnes of sulphur dioxide into the stratosphere, causing a 0.6°C global temperature drop.
  • SAI’s impact on agriculture varies based on factors like precipitation and solar radiation.

Understanding Ideal Temperatures for Crops

  • Knowing the optimal global temperatures for crop growth is crucial.
  • Computer models evaluate SAI’s effects on crops like maize, rice, soybean, and spring wheat.

Crop Production under Climate Change

  • Uncontrolled climate change favors crop production in cold, high-latitude regions like Canada and Russia.
  • Moderate SAI levels could boost food production in temperate regions like North America and Eurasia.
  • Large-scale climate intervention could enhance agricultural output in tropical areas.

Regional Variation in SAI

  • Nations may choose different SAI levels to maximize crop yields, considering their geographical and climatic conditions.
  • Additional Considerations
  • The study highlights the need to explore other consequences of SAI, including impacts on human health and ecosystems.

Stratospheric Aerosol Intervention (SAI)

SAI is a proposed solar geoengineering technique aimed at mitigating global warming.

It involves introducing aerosols into the stratosphere to create a cooling effect.

Mechanism of SAI

  • The process mimics natural occurrences like volcanic eruptions, which lead to global dimming and increased albedo, naturally cooling the Earth.
  • Albedo refers to the Earth’s surface reflecting more sunlight back into space, reducing heat absorption.

Unintended Consequences

  • While SAI offers a potential solution to global warming, it raises concerns about unintended side effects.
  • Possible consequences may include damage to the ozone layer, alterations in the hydrological cycle, changes in monsoon systems, and impacts on crop yields.

Geoengineering Techniques

  • Geoengineering refers to the deliberate large-scale intervention in the Earth’s climate system to combat climate change.

Categories of Geoengineering Techniques

  • Geoengineering interventions typically fall into two categories: Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM).
Carbon Dioxide Removal (CDR)

CDR techniques aim to remove excess carbon dioxide from the atmosphere, thus reducing the greenhouse effect.

Examples of CDR Techniques
  • Afforestation and Reforestation:
    • Planting trees or restoring forests to enhance the natural absorption of carbon dioxide by vegetation.
  • Biochar:
    • Converting biomass into charcoal and burying it in the soil to increase carbon storage.
  • Bioenergy with Carbon Capture and Storage (BECCS):
    • Growing crops for biofuel production, capturing emitted carbon dioxide during combustion, and storing it underground or in the ocean.
  • Ocean Fertilization:
    • Adding nutrients like iron or nitrogen to the ocean to stimulate phytoplankton growth, which consumes and transfers carbon dioxide to the deep ocean.
Solar Radiation Management (SRM)

SRM techniques aim to reduce the amount of solar energy reaching the Earth’s surface, leading to global cooling.

Examples of SRM Techniques
  • Stratospheric Aerosol Intervention (SAI):
    • Introducing aerosols into the stratosphere to create a cooling effect by reflecting sunlight.
  • Space-Based Reflectors (SBR):
    • Placing mirrors or devices in Earth’s orbit to deflect or block incoming sunlight.
  • Marine Cloud Brightening (MCB):
    • Spraying sea water droplets or substances into low-level clouds over the ocean to increase their reflectivity and albedo.
  • Cirrus Cloud Thinning (CCT):
    • Reducing the formation or persistence of high-level cirrus clouds that trap heat by seeding them with ice crystals or other agents.
  • Surface Albedo Modification (SAM):
    • Changing the reflectivity of land or sea surfaces by methods such as painting roofs white, covering deserts with reflective sheets, or increasing ice cover.

-Source: Down To Earth

April 2024