This geoengineering technique falls under the category of solar radiation management (SRM) and aims to reduce the amount of sunlight entering the earth’s atmosphere by putting tiny, reflective particles into the stratosphere. The 1991 eruption of Mount Pinatubo in the Philippines spewed twenty million tonnes of sulfur dioxide into the stratosphere and the entire planet cooled 0.4 to 0.5°C. Although the idea of artificial volcanoes was first proposed in 1977, the concept has undergone refinement in recent years. Scientists estimate that a 2% reduction of sunlight could negate the temperature-rise resulting from of a doubling of atmospheric CO2. Advocates envisage executing this technique regionally, most likely over the Arctic, in order to stall the disappearance of, or even to replenish, ice. The particles would be blasted by jets, fire hoses, rockets or chimneys. “Plan B,” par excellence, this technique is promoted as an “emergency” measure that would bring results quickly and be inexpensive.
Blasting particles into the atmosphere is getting more attention than any other geoengineering technology. The U.S. Defense Advanced Research Projects Agency (DARPA) has looked at possible methods for distributing the particles and NASA has researched the impacts of aerosols on climate change. The Novim Group, a new California-based outfit with a mission to present “clear scientific options…without advocacy” issued their first report on climate engineering in August 2009, which focused on artificial volcanic eruptions. Steven Koonin, now Under Secretary for Science at the U.S. Department of Energy, was a lead author. This study proposes an agenda for research, development and deployment.
What’s wrong with artificial volcanoes?
Slowing down or stopping the rate of warming via solar radiation management does nothing to change the levels of CO2 in the atmosphere, so symptoms are addressed but not causes. Even advocates admit that stratospheric sulfates have many unknown impacts, but there is research already suggesting:
• There will be damage to the ozone as sulfate particles in the stratosphere provide additional surfaces for chlorinated gases such as CFC’s and HFC’s to react.
• The ability to target particles in the specific areas where sunlight needs to be reduced (i.e., Arctic or Greenland) is highly speculative and it is likely the particles would be diffused elsewhere.
• It is likely that precipitation levels will be decreased in some regions. Large volcanic emissions of sulfate particles have in the past been accompanied by failed monsoons and extended drought in tropical latitudes.
• Preliminary modeling suggests a rapid rise in temperature if the programme were to be started and then stopped. Such a rapid rise would be more dangerous to life on earth than a gradual rise.
• Reduced sunlight could undermine the amount of direct solar energy available and disturb natural processes such as photosynthesis by altering the wavelength of incoming sunlight.
• What goes up still (usually) comes down. The tonnes of particles that would need to be regularly blasted into the stratosphere will find their way back to earth again. All the issues related to environmental health and safety associated with particulate pollution, including novel manufactured nanoparticles, remain relevant for intentional polluting schemes.
• Geoengineering the stratosphere makes it easier for industry to continue its own atmospheric pollution.