Solar geoengineering might work but local temperatures could keep rising for years
- September 30, 2022
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Solar geoengineering might work but local temperatures could keep rising for years
Subject : Environment
Context:
Theoretically, aerosol particles would reflect a little more sunlight back to space, dampening the effects of global warming, but research shows that temperatures locally or regionally might continue to increase over the following few years.
Different Types of Solar geoengineering:
Type of Solar geoengineering | Pros | cons |
Aerosol injection
This technique includes Spraying aerosols high up into the stratosphere to cool the planet. It works in a similar way to a large volcanic eruption.
Sulphur dioxide is often proposed as the most likely candidate for aerosol release. However Sulfuric acid or hydrogen sulphide could also be used.
| · It could have a large cooling effect on earth’s climate. · Releasing aerosols could also help to bring back global rainfall patterns to their pre-industrial averages. · It has an edge on other proposed forms of solar geoengineering because it would not require a large technological leap to become a reality | · Its benefits are dependent on how aerosols are used. Research finds that releasing aerosols in just the northern hemisphere could lead to a decrease in rainfall and, therefore, an enhanced drought risk – in India and the African Sahel. · Other concerns are that that, if aerosols were used to address global warming, the world could be left at risk of a “termination shock”. That is, if aerosols were released and then suddenly stopped – as a result of political disagreement or a terrorist attack, for example global temperatures could rapidly rebound. · Using sulphur dioxide in aerosol spray has its own concern. It could come down as acid rain. |
Marine cloud brightening In theory, it involves using ships to spray saltwater into the clouds above the sea. Once airborne, the salt particles would act as cloud condensation nuclei, they would facilitate the condensation of water vapour into liquid. As more water droplets are created, clouds would appear larger and brighter. These brighter clouds would reflect away more sunlight. In simple words it means making existing clouds just a little bit brighter which could help cool planet. | · It could be, in theory, be used over very specific areas of concerns like to just cool over coral reefs or it may be possible to only cool in one particular region of earth. · A few studies based on modelling suggest that marine cloud brightening may be able to restore temperatures and ice cover, and could have a “mixed” impact on global crop yields. | · It may have a large and very localised effect and that could lead to much more regional variation in the climate response. This variation could possibly lead to unfavourable weather in some parts of the world. |
High-albedo crops and buildings It includes increasing the albedo of buildings in order to reflect more sunlight. This would involve making rooftops and walls brighter – by painting them white, for example. Scientists have also suggested that the same technique could be applied to crops, possibly by introducing genes that would give plants a waxy sheen. | · In cities, it could potentially help reduce the highest temperatures to reduce health problems for the population during heatwaves · The technique could be used on a smaller scale than other proposed technologies. This means the risk of issues, such as “cross-boundary conflict” and termination shock, could be much smaller. | · Unlikely to make a large difference to global temperatures.
· It might hamper crop productivity and, thus, food production. |
Ocean mirror This would involve using a fleet of sea vessels to churn up millions of tiny microbubbles on the ocean surface. The seafoam formed would reflect away sunlight, cooling the planet | · The reflectance of ocean foam can be more than ten times higher than the ocean itself and the ocean occupies 71% of our planet’s surface so enhancing sea foam is a sensible and simple way to reflect a few per cent more sunlight · In case if anything goes wrong, it is faster and easier to shut ocean foam. | · It could reduce the amount of sunlight reaching below the ocean’s surface, which may negatively impact marine ecosystems · creating enough microbubbles at the ocean’s surface to have an overall cooling effect on the planet could require large amounts of energy.
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Cloud thinning
It means to “remove” cirrus clouds from the atmosphere. Cirrus clouds are thin, wispy clouds made of ice crystals, which form at high altitudes. The clouds reflect away some sunlight, but also absorb large amounts of long-wave radiation – meaning that, on balance, they warm the planet.
Aerial vehicles such as drones could be used to deliver and then inject solid aerosol particles, such as desert dust or pollen, into cirrus clouds. Seeding the clouds in this way would cause them to dissipate more quickly, lessening their overall warming effect. |
· If we could remove all cirrus clouds, we could more than offset the warming caused by a doubling of CO2. | · Overseeding could lead to the formation of thicker and more persistent cirrus clouds. The effect could be additional warming rather than the intended cooling. |
Space sunshades · It involves sending a giant mirror – or fleet of mirrors – into orbit in order to reflect away more sunlight from the Earth | · Since sunshades are implemented in space and, hence, environmentally they are the least disruptive. | · It would be a huge technological challenge. Once introduced, it would need to be continually altered to deal with further rises in atmospheric CO2
· The costs are probably expensive when we compare with other solar geoengineering techniques |
Advantages of geoengineering | Disadvantages of geoengineering |
· Geoengineering can hold global warming to 1.5C. These technologies could theoretically lower global warming and help in the effort to fight climate change. | · Geoengineering could be viewed by many as a quick “technofix” to climate change. If more research and development is channelled into these techniques, people may start to backpedal on their promises to cut their greenhouse gas emissions. · Since geoengineering would not affect the climate the same way [as mitigation], a lower global mean temperature anomaly achieved using geoengineering does not necessarily lead to lower aggregate climate risks · The technologies involved in this process are very costly. · There is also the issue of governance. Though ideas are beginning to emerge, it is still not clear who could be responsible for carrying out and regulating solar geoengineering. At present, research into solar geoengineering is largely restricted to the US, the UK and other parts of Europe. However, developing countries are likely to be the most affected by future climate change, research shows. Therefore, “it is right” for these nations to play “a central role in solar geoengineering.
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Mount PinatuboVolcanic eruption in 1991cooled the planet by about half a degree Celsius on average for many months. |
Geoengineering is at best a supplement to emissions cuts, not a substitute for them. It is possible that a combination of emissions cuts, carbon removal and solar geoengineering could provide a significantly safer climate than emissions cuts alone or emissions cuts and carbon removal.