Science

The Strange Role of Chemtrails in the Debate About Fixing Climate Change

Scientists at the University of California, Berkeley say global-scale geoengineering would likely harm agricultural crops and lower yields. 

A plane flying through the sky leaving chemtrails behind it
planes, moon, nature / Flickr

After stoking irrational fears from paranoid skywatchers and climate deniers for decades, it turns out that seeding the sky with sulfate aerosols to curb climate change isn’t the solution we’re looking for. But it sure took us a shockingly long time to get here.

The concept, sometimes called climate engineering, but most commonly known as geoengineering, originated with President Lyndon Johnson’s Science Advisory Committee in 1965 — during those Dr. Strangelove years of the Cold War when impossibly bad, just plain stupid and terrible government proposals enjoyed a brief golden age. As part of what is arguably the first government report on the potential gravity of climate impacts from fossil fuels, LBJ’s science advisors suggested that it might be possible to counterbalance these warming trends by “spreading very small reflecting particles over large oceanic areas” in order to raise “the albedo, or reflectivity, of the Earth.”

Public awareness and anxiety about this admittedly not-especially-great idea, however, did not really begin until 1996, when a weather modification paper by the U.S. Air Force lit up the early internet, founding its way inevitably onto a bizzaro paranormal and parapolitcal AM radio talk show hosted by the late Art Bell, Coast to Coast AM.

Regardless, it’s everywhere now, a not remotely well-substantiated accusation that the government has already put this plan into action, poisoning us all in the process, etc., etc., a global agenda, etc.

Well, everyone can now rest assured that this project (if it ever stood a chance) is likely to be mothballed forever: new research led by a team at the University of California, Berkeley’s Global Policy Laboratory have determined that spraying the upper atmosphere with gases like carbonyl sulfide to create stratospheric sulfur aerosols from a photochemical reaction would likely be counterproductive to the task of mitigating climate change. The group published their results Wednesday in the journal Nature.

“The breakthrough here,” according to the co-lead author Solomon Hsiang, an associate professor of Public Policy at UC Berkeley, speaking in a prepared statement, “was realizing that we could learn something by studying the effects of giant volcanic eruptions that geoengineering tries to copy.”

In one form of solar geoengineering, sulfate aerosols, similar to those present in volcanic eruptions, are injected into the atmosphere. The resulting haze reflects sunlight and the heat of solar radiation back out into space, reducing the thermal load on the planet's atmosphere.

Stephen McNally and Hulda Nelson, UC Berkeley

What Is Geoengineering?

Part of the idea for this form of geoengineering came from the visible cooling effect produced by massive volcanic eruptions, like the one from Mt. Pinatubo in the Philippines in 1991.

Pinatubo propelled roughly 20 million tons of sulfur dioxide into the atmosphere. The resulting stratospheric sulfur aerosols reflected about 2.5 percent of the sunlight that would normally hit Earth’s surface back out into space. Climate scientists calculated that these aerosols brought the average global temperature down by close to one degree Fahrenheit, or about half a degree Celsius.

What the Berkeley team did was study satellite data on these sulfur aerosols, from volcanic eruptions and other phenomena, in tandem with agricultural data on maize, soy, rice and wheat production from 105 countries between the years 1979 and 2009. In association with researchers from UC San Diego, Stanford, and Columbia, the team calculated that losses of sunlight would undermine the growth of crops and cancel out any of the benefits that might come from shielding them from any extreme heat.

“We are the first to use actual experimental and observational evidence to get at the total impacts that sulfate-based geoengineering might have on yields,” according to the study’s lead author Jonathan Proctor, a UC Berkeley doctoral candidate in the Department of Agricultural and Resource Economics, in a statement. “Before I started the study, I thought the net impact of changes in sunlight would be positive, so I was quite surprised by the finding that scattering light decreases yields.”

Overall, Proctor thinks that there are a lot of risks and a lot of unknowns surrounding the idea of large-scale geoengineering — and that a great deal more study is needed before even thinking of implementing something that would tweak the whole world’s atmosphere. (This is something that most chemtrails conspiracy theorists would probably agree with.)

“Society needs to be objective about geoengineering technologies and develop a clear understanding of the potential benefits, costs and risks,” Proctor says. “At present, uncertainty about these factors dwarfs what we understand.”

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