Global Dimming - Possible Use To Mitigate Global Warming

Possible Use To Mitigate Global Warming

Further information: Mitigation of global warming and Albedo

Some scientists have suggested using aerosols to stave off the effects of global warming as an emergency geoengineering measure. In 1974, Mikhail Budyko suggested that if global warming became a problem, the planet could be cooled by burning sulfur in the stratosphere, which would create a haze. An increase in planetary albedo of just 0.5 percent is sufficient to halve the effect of a CO₂ doubling.

The simplest solution would be to simply emit more sulfates, which would end up in troposphere - the lowest part of the atmosphere. If this were done, Earth would still face many problems, such as:

• Using sulfates causes environmental problems such as acid rain
• Using carbon black causes human health problems
• Dimming causes ecological problems such as changes in evaporation and rainfall patterns
• Droughts and/or increased rainfall cause problems for agriculture
• Aerosol has a relatively short lifetime

The solution actually advocated is transporting sulfates into the next higher layer of the atmosphere - stratosphere. Aerosols in the stratosphere last years instead of weeks - so only a relatively smaller (though still large) amount of sulfate emissions would be necessary, and side effects would be less. This would require developing an efficient way to transport large amounts of gases into stratosphere, many of which have been proposed though none are known to be effective or economically viable.

In a blog post, Gavin Schmidt stated that "Ideas that we should increase aerosol emissions to counteract global warming have been described as a 'Faustian bargain' because that would imply an ever increasing amount of emissions in order to match the accumulated greenhouse gas in the atmosphere, with ever increasing monetary and health costs."