If you look at the temperature records since the late 1800s, the increase in global temperatures has not been consistent with the increase in atmospheric CO2. In fact, temperatures decreased significantly from the 1950s to the 1970s.

This decline coincided with overall post-war increases in industrial production and coal-fired power generation. A byproduct of burning coal was the release of sulfur dioxide into the atmosphere, which, in turn, resulted in a lot of sulfuric acid haze in the stratosphere. This haze reflected incoming solar radiation, resulting in overall cooling of the atmosphere worldwide.

Then in 1970, President Nixon signed the Clean Air Act.

Before the Clean Air Act (and similar legislation in Europe) sulfur emissions from power plants and vehicles caused significant air pollution, leading to acid rain, which caused widespread environmental damage to the environment too numerous to list here. One of the requirements of the act was to decrease power plant and vehicle sulfur dioxide emissions.

Once sulfur emissions started to decline, acid rain decreased sharply throughout the industrialized world. In addition, temperatures again started to increase and did so quite rapidly, a purely unintended consequence of the act.

So what is the lesson here? If you don’t think humans can change the climate, you’d be wrong. The history of human sulfur dioxide emissions proves it.

One of the proposed “solutions” to global warming is injecting sulfur dioxide into the stratosphere. This proposal is being taken seriously, especially by conservative think tanks who call themselves climate change skeptics. Oh the irony.

History shows that we would have to continuously inject sulfur dioxide at high altitudes to cool the Earth and we would have to burn fuel to do so, adding CO2 to the air as well. The moment we stopped, temperatures would soar. Then there is acid rain and its devastating ecological impacts including ozone depletion. The uneven application of this “solution” could cause massive droughts in areas that depend on annual monsoons. Who would manage this process is another question fraught with geopolitical peril.

Seems to me that the better course is to decrease CO2 emissions, not add a different kind of pollution to the atmosphere. Decreasing emissions is something we already know how to do.