The risk of planetary geoengineering

The phenomenon of Mount Pinatubo’s eruption reducing global temperatures has led scientists to consider geoengineering as a solution to global warming. However, past attempts at weather control, such as Project Cirrus in the 1940s, have had unintended and devastating effects, raising concerns about the unpredictability and potential dangers of implementing such large-scale interventions.

This article was first published in The Mint. You can read the original at this link.

In 1991, when Mount Pinatubo in the Philippines erupted, it spewed over 20 million tonnes of sulphur into the upper atmosphere. Shortly thereafter we began to witness a strange phenomenon. The sulphates in the stratosphere were acting as a sort of a sun visor, shielding the earth from the sun’s rays and reducing global temperatures by nearly half a degree Celsius by the end of the year.

This phenomenon has lead various scientists from around the world to seriously consider whether replicating the effects of this volcanic activity might in fact be a surer solution to the problem of global warming than reducing carbon emissions. David Keith of Harvard University has created a detailed plan involving the use of a fleet of 10 Gulfstream jets that will inject 25,000 tonnes of sulphur every year into the lower stratosphere—ramping up, by 2070, to a million tonnes per year. According to Keith’s calculations, if we implement this project, the world, which would otherwise have warmed by 2 degrees centigrade by the end of the century, would instead only warm by 1.

This is geoengineering on a planetary scale and some think this is the only solution to a climate change crisis that we have been unable to address through lifestyle changes. However, before we go down this path we would do well to consider an earlier attempt at controlling the weather that didn’t end so well.

In the 1940s, the GE Research Laboratory was developing technology to make clouds spontaneously precipitate when seeded with dry ice. Their partnership with the Army Signal Corps—Project Cirrus—was set up with a clear eye on controlling the weather. They focussed their initial attention on storms, hoping to learn enough to prevent damage to crops and homes. They knew they couldn’t “bust" a hurricane with dry ice, but they hoped to be able to at least divert weather systems away from land. In their first attempt, they took on a hurricane heading to Jacksonville. A Project Cirrus plane dropped dry ice along the edge of the squall line and, almost instantly, the clouds shed rain over the sea. This was the result they were anticipating and they hoped that this would cause the storm to change its direction.

While the storm initially turned away as they hoped, it soon made a dog-leg turn over the Atlantic and headed back to the mainland with renewed vigour. The resulting Frankenstein’s monster of a storm was more vicious than before, its winds gusting at a hundred miles an hour by the time it made landfall over the Savannah. It smashed windows, flattened sugarcane fields and caused upwards of $23 million of damage.

Despite this initial setback, Project Cirrus continued to experiment with the weather, developing newer technologies and alternative seeding materials. In 1950, Project Cirrus’ silver iodide generators allegedly caused so much rainfall that they replenished New York’s depleted reservoirs with nearly 2 billion gallons of water ending an unseasonal drought that threatened the residents of the largest metropolis in the country. However, while New York City rejoiced, the neighbouring Orange and Sullivan counties suffered tremendous losses. Their crops washed out and tourist income became all but non-existent for the season. As a result, New York City had to defend over 130 compensation claims for damage caused by its man-made storm.

It soon became evident, even to its most ardent supporters, that attempting to control something as complex as the weather was near impossible. The atmosphere is constantly in a state of flux and the alteration of one parameter sets in motion a cascade of changes that has effects on the other side of the planet. The phrase a flap of a butterfly’s wings in Brazil can set off a tornado in Texas came to perfectly sum up the problem, eventually becoming the strapline for chaos theory. As a result, we soon gave up even attempting to control the weather, contenting ourselves, instead, with merely trying to understanding it better so that we could take precautions whenever possible to mitigate its effects.

However, that was a long time ago. As the need to find ways to reverse our impact on the environment has become more urgent, we have begun to consider radical solutions. If interest in geoengineering is anything to go by we might, in our haste, end up forgetting the lessons of our past.

It is worth noting that, as promising as it this sounds, solar geoengineering at a planetary scale is unpredictable and fraught with concern. Even if implemented well, it is likely to have a differing impact on different parts of the planet. Attempting to counteract the greenhouse effect by reducing sunlight is likely to make the planet drier by reducing evaporation so much that it could result in a 1% reduction in rainfall for every degree centigrade of warming counteracted. While sulphates in the upper atmosphere usually dissipate after a few years, sustained use over an extended period could have lasting effects on atmospheric chemistry creating ozone-eating compounds that could lead to an increase in skin cancers and ultraviolet damage to plants.

As much as we feel the need for an urgent solution to global warming, we would be wise to fully consider the consequences of any action we take at a global scale. After all, if the experiment that Project Cirrus attempted had such devastating effects on the local environment, geoengineering on planetary scale could well destroy our planet.