In News:

• A new study in Geophysical Research Letters suggests that diamond dust could be more effective than any other material in reflecting solar radiation.
• Objective: The goal is to reduce global temperatures by 1.6°C by spraying approximately 5 million tonnes of diamonds annually into the atmosphere.

Background of Geoengineering Solutions:

• Geoengineering refers to large-scale interventions aimed at altering Earth's natural climate system to counteract global warming.
• One proposed solution involves spraying diamond dust in the Earth's upper atmosphere to cool the planet.
• This approach is part of Solar Radiation Management (SRM), which seeks to reflect sunlight away from Earth, thereby reducing global temperatures.
• Previous Materials Considered: Sulphur, calcium, aluminium, silicon, and other compounds have been studied to perform a similar function.

Context of Geoengineering and Climate Crisis:

• Inadequate Progress: Current efforts to mitigate global warming, such as reducing greenhouse gas emissions, have been insufficient. Global temperatures have continued to rise, and targets like the Paris Agreement's 1.5°C are increasingly out of reach.
• Rising Global Temperatures:
  • 2023: Global temperatures were approximately 1.45°C higher than pre-industrial levels.
  • Projected Challenge: To meet the Paris goal, global emissions must be reduced by at least 43% by 2030. However, current actions will likely result in only a 2% reduction by 2030.

Geoengineering Technologies:

• Geoengineering Methods:
  1. Solar Radiation Management (SRM): Reflects sunlight to cool Earth.
  2. Carbon Dioxide Removal (CDR): Involves capturing and storing CO?.
• SRM Techniques:
  • SRM draws inspiration from natural events like volcanic eruptions, where large amounts of sulphur dioxide form particles that reflect sunlight.
  • Mount Pinatubo (1991): One of the largest eruptions, which temporarily reduced global temperatures by 0.5°C due to the sulphur dioxide released.

Diamond Dust vs Other Materials:

• Study Comparison: Diamonds were found to be the most effective material compared to other compounds (sulphur, calcium, etc.) for reflecting solar radiation.
• Quantity Needed: To achieve a cooling of 1.6°C, 5 million tonnes of diamonds would need to be dispersed into the upper atmosphere each year.

Broader Geoengineering Context:

• Carbon Capture and Storage (CCS):
  • CCS is already in practice, where CO? emissions from industries are captured and stored underground to reduce atmospheric carbon.
  • However, CCS faces high costs and scalability issues, and safe storage sites for CO? are limited.
• Direct Air Capture (DAC): A more advanced method where CO? is directly removed from ambient air, but it faces even greater challenges in terms of infrastructure and cost.