Nature does the sulfur aerosol experiment for us every couple of hundred years or so. Large volcanic eruptions put far more sulfur in the stratosphere than we

Nature does the sulfur aerosol experiment for us every couple of hundred years or so. Large volcanic eruptions put far more sulfur in the stratosphere than we are contemplating using. The 1815 Mount Tambora eruption, the largest in recent history, dropped global temperatures by 0.4 to 0.7 °C [0], badly disrupting agriculture. Although the eruption, the tsunami, and the volcanic winter obviously all caused substantial loss of life, it's not clear that there were any long-term global effects besides more colorful sunsets. Also, the half-life of sulfur aerosols in the stratosphere is on the order of a few months. If we overdo it or discover some previously-unsuspected downside, all we have to do is stop, and the effects will fade out in a reasonable amount of time. Caution is certainly warranted, but running away screaming is not. The biggest problem with the sulfur aerosol approach is mentioned in the article: it does nothing to help with ocean acidification, which is also a serious consequence of increasing carbon dioxide concentrations. [0] http://en.wikipedia.org/wiki/Year_Without_a_Summer http://en.wikipedia.org/wiki/Year_Without_a_Summer