What is Geo engineering?

• It refers to deliberate, large-scale intervention carried out in the Earth’s natural systems to reverse the impacts of climate change.
• This involves techniques to physically manipulate the global climate to cool the planet.
• Geo engineering technologies mainly consist of Carbon Dioxide removal technologies and Solar radiation management.

Carbon dioxide Removal Technologies

• • Carbon dioxide removal (CDR) is a process in which carbon dioxide is removed from the atmosphere and durably stored in geological, terrestrial, or ocean reservoirs. Some proposed techniques include:
    • Bioenergy with Carbon Capture and Storage: It refers to capturing and sequestering  CO2 from bioenergy processes (e.g. ethanol production or burning biomass for electricity).

• Ocean Fertilization: It refers to dumping iron sulphate into the ocean to stimulate the growth of phytoplanktons which absorb atmospheric CO2.

• Enhanced Photosynthesis: This technique proposes to genetically manipulate plants and algae, so that they would metabolize more CO2.

Solar Radiation Management

• It is a geoengineering technique which aims to reflect a small proportion of the Sun’s energy back into space. This counters the temperature rise caused by increased levels of greenhouse gasses in the atmosphere which absorb energy and raise temperatures. Some proposed techniques include:
  • Albedo enhancement: It refers to increasing the reflectiveness of clouds or the land surface so that more of the Sun’s heat is reflected back into space.
  • Space reflectors can help block a small proportion of sunlight before it reaches the Earth.
  • Stratospheric Aerosol Injection (SAI): It refers to introducing small, reflective particles into the upper atmosphere to reflect some sunlight before it reaches the surface of the Earth.

Limitations in the use of geoengineering technologies

• These technologies are expensive and their viability needs to be effectively studied.
• Aerosol sprays contain ozone depleting substances which can lead to ozone layer depletion.
• Aerosol injections can cause rapid warming  leading to biodiversity loss and food security challenges.