Modern humans are a couple of hundred thousand years old at best – compare that with cockroaches at 350 million years old. Regardless, in our short time on the planet we have worked tirelessly to modify our surrounds to our purposes. Minor reservoirs and irrigation channels are a few thousand years old.
Widespread modification of the soil in the Amazon basin over a thousand years ago was accomplished by building up polders in swampy areas then adding charcoal, bone, pottery shards, and nutrients to greatly improve soil productivity. The result was “terra preta do indio,” a Portuguese phrase meaning black earth of the Indian.
Prior to European colonization of north America, Indians use fire to modify the environment, maintaining grasslands which were more productive for game animals. What many colonists described as a pristine wilderness was actually a maintained mosaic of grasslands and forests.
These small scale environmental modifications pale in comparison to our current unintentional change to the global climate. From wildfires to floods, and hurricanes to droughts, we are having a negative impact on the climate. To retard further degradation of the climate we must rapidly decarbonize our energy systems. The environmental response to this action is however slow.
If we can unintentionally change the climate, surely we can intentionally make it right, right? We can do things to reverse the warming in the atmosphere? There is a recent natural precedent for global climate impact. In 1991, Mount Pinatubo in the Philippines erupted violently, sending tens of billions of tonnes of ash and sulfur oxides in the stratosphere. The ash and especially sulfate particles circulated around the world, partially shading the earth. A drop of 0.6 degrees Celsius was recorded in the global mean temperature for 1991-1992.
So there you go, all we need to do is inject massive amounts of sulfur into the stratosphere. The sunlight will be partially shaded, cooling the earth and reversing the heat driven climate change. An engineering research group proposed just such an experiment. Billions of tonnes of molten sulfur would be delivered to the stratosphere via specially designed jet tankers. These would fly sixty thousand flights per year for decades. The scheme has been described as the cheapest and quickest way to cool the planet.
BUT, there is a lot of devilment in the details. Even moderate success may take the pressure off the need to decarbonize our energy systems. This would do nothing to address the damage to the oceans via acidification from the dissolved Carbon Dioxide. And that sulfur mist in the atmosphere? It turns into sulfuric acid, which would untimely rain down on the planet.
A uniformly gray sky could negatively impact crops, energy production from solar and wind, and even seriously change weather patterns – just the opposite of what was desired. A worst-case outcome would be international strife if the experiment did not have a global consensus.
Dr. Bob Allen, Ph.D., is Emeritus Professor of Chemistry at Arkansas Tech University.