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News: With record-breaking heatwaves hitting many parts of the world, scientific circles have been debating whether countries should prepare to deploy geoengineering technologies to deal with such climate emergencies or not.
What is Geoengineering?
Geoengineering is an umbrella term for various experimental technologies designed to deliberately alter the climate system to reduce the impacts of global warming. They are broadly fall under two categories: Solar Radiation Modification (SRM) technologies and Carbon Dioxide Removal (CDR) technologies.
Premier universities such as Cambridge and Harvard have set up specialised geoengineering research centres. There are a few geoengineering modelling programmes in India as well.
What are Solar Radiation Modification (SRM) technologies?
SRM aims to reduce the amount of solar radiation reaching Earth by reflecting sunlight back into space, thereby reducing surface temperatures. Scientists are proposing to do this by a variety of techniques such as making clouds brighter, thereby reflecting sunlight like a mirror. Or by thinning/ removing the ‘cirrus clouds’ that absorb solar radiations and warm the earth. These technologies are attracting the most attention.
SRM has many techniques. Such as,
Cloud engineering: Countries have been seeding clouds to force more rainfall for years. China has been implementing an extensive cloud seeding programme, with plans to cover more than half of the country by 2025. In India, cloud seeding has been tried in states such as Tamil Nadu, Karnataka and Maharashtra during droughts.
These practices have encouraged scientists to propose cloud engineering of the planet to reduce warming. But still, cloud engineering is in the ideation stage.
Stratospheric Aerosol Injection (SAI): It is one of the technologies that has reached the experimentation stage. SAI aims to mimic large volcanic eruptions that have a cooling effect on the globe. During large eruptions, millions of tonnes of sulphur particles (called aerosols) are injected into the upper atmosphere, where they reflect back the incoming solar radiations, thereby cooling the planet.
For example, the eruption of Mount Pinatubo in the Philippines in 1991 caused global cooling of 0. 6°C for the following two years. Scientists are now proposing to send aeroplanes and balloons to the stratosphere to release millions of tonnes of aerosols to mimic a smaller version of Mount Pinatubo.
What are Carbon Dioxide Removal (CDR) technologies?
CDR is about removing carbon from the atmosphere, either by the massive deployment of machines to extract CO2 from the air or by more natural methods like planting trees.
What are the advantages and disadvantages associated with the Stratospheric Aerosol Injection (SAI)?
Advantages: Several modelling studies indicate that SAI might reduce some of the worst effects of climate change, such as lowering warming and reducing the frequency of heatwaves and high-intensity storms.
Also, the price is so affordable that a few dozen countries can easily deploy this technology unilaterally.
Disadvantages: a) SAI might create unintended consequences such as adverse impacts on rainfall, crop production and ocean acidification, b) Large-scale spraying of aerosols into the atmosphere could also deplete the ozone layer, enlarging the ozone hole, c) If the aerosol injection is terminated abruptly this will cause rapid warming, disrupting the water cycle and leading to massive biodiversity loss, d) Unilateral use of SAI could lead to significant adverse effects in other countries, leading to conflicts.
What will be the future of geoengineering techniques?
The best way to solve the climate crisis is by cutting down the global emissions. But environmentalists fear that the excessive focus on geoengineering would move the focus away from cutting emissions.
Countries will deploy geoengineering on a large scale only if they fear large-scale casualties or economic disruptions due to extreme climatic events.
Before deploying, a) enough research must be done about the safety and effectiveness of these technologies, b) A global governance mechanism based on international rules-based system must be established to deter the unilateral deployment of these technologies, c) Better to be prepared for the consequences.
India should take the lead from the global South in developing scientific knowledge on the subject.
Source: The post is based on the article “Do We Need Geoengineering & What Are The Risks?” published in “The Times of India” on 23rd June 2022.