Tuesday, November 3, 2015

Scientist from Harvard Sugest Diamond Dust as an Alternative to Climate Change

Injecting solid dust in the stratosphere could be a feasible "geoengineering" to counter the climate changes.

Geoengineering has been defined as an approach to the climate change problem. The Royal Society defines geoengineering as "deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change". It is dividen into two basic categories:
  1. Carbon Dioxide Removal techniques.
  2. Solar Radiation Management techniques, which reflect a small percentage of the sun's light and heat back into the space.
Climate scientists have thought up plenty of futuristic ways to cool the planet, but a recent study suggest a new idea: spraying diamond dust in the stratosphere. Solid aerosol particles have been proposed as an alternative to sulfate aerosols for solar geoengineering. A team of scientist from Harvard University in Cambridge, Massachusetts, in their paper published in Atmospheric Chemistry and Physics suggest that nanoparticles of diamond and aluminum oxide could be more effective and less environmentally damaging than sulphate due to in atmosphere, sulphate can produce sulphuric acid, which is a problem to the ozone layer, also, by absorption of certain wavelengths, they heat up the lower stratosphere, it could affect air-circulation patterns and climate. This problem isn't present when alumina and diamond are used, it is because they don't produce sulfuric acid and absorb particular wavelengths of light in a different way. Alumina dust would achieve a similar cooling effect to that sulphate sprays, but diamond dust would be at least 50% more effective.
There are different problems with the application of this project, one of the most important is the cost of diamond dust, this is less expensive than cut gemstones, but the cost still being high (less than US$100 per kilogram), however, according to the results of the paper, the amount of human-emitted greenhouse gases would take hundreds of thousands of tonnes of dust annually.
In another paper, David Keith says that by 2065 the population of the planet will be among 10 billion people, and the cost might be of $5 per person to pump up 450,000 tons of dust.
In spite of the disadvantages of sulphate, it is well studied and understood, however, the risk of both alumina and diamond nanoparticles are unknown, although the Harvard researchers are doing la test to remedy that. 
Recent studies suggest that solid dust could significantly lower some of the risks associated with sulphates.

  • Weisenstein, D. K., & Keith, D. W. (2015). Solar geoengineering using solid aerosol in the stratosphere. Atmospheric Chemistry and Physics Discussions, 15(8), 11799-11851.
  • http://www.geoengineeringwatch.org/


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