Spraying aerosols into the atmosphere to reduce global warming is possible, but it will be very costly with current technology.
With reports that the Earth is heading rapidly to a hothouse state, researchers looked at the capabilities and costs of various methods proposed to inject sulfates into the lower atmosphere to reflect sunlight back into space. The strategy could offset the negative effects of global warming of the world fails to control the emission of greenhouse gases.
Stratospheric Aerosol Injection: Will It Work?
The idea of injecting sulfates into the atmosphere was inspired by major volcano eruptions. In 1991, Mount Pinatubo in the Philippines erupted, sending about 20 million tons of sulfur dioxide aerosols into the stratosphere.
As a result, the temperature in the lower atmosphere dropped by 1 degree Fahrenheit. Eventually, the effect wore off when the sulfates dropped back to the ground a few years later.
Cost Of Offsetting Global Warming With Sulfates In The Atmosphere
"While we don't make any judgment about the desirability of SAI [stratospheric aerosol injection], we do show that a hypothetical deployment program starting 15 years from now, while both highly uncertain and ambitious, would be technically possible strictly from an engineering perspective," revealed Gernot Wagner from Harvard University and co-author of the study. "It would also be remarkably inexpensive, at an average of around $2 billion to 2.5 billion per year over the first 15 years."
However, Wake Smith of Yale University, the co-author of the study, warned that the project would need an entirely new kind of plane to deliver the sulfates to the lower atmosphere. He stated that currently, no existing aircraft has the capacity to reach the altitude required and carry the payload.
The researchers investigated how much it would cost to develop a new aircraft specifically to inject the sulfate into the atmosphere. They dubbed it SAIL or SAI Lofter, which has equal the weight of a large but narrow passenger aircraft and can sustain a level flight at 20 kilometers per second.
In addition, the SAI Lofter should have a wing area twice the size of a regular airliner, double the thrust, and four engines. They estimated that it would cost $2 billion to develop the airframe and then $350 million to modify an existing aircraft.
Doubts and concerns have previously been expressed over the impact of injecting the atmosphere with millions of tons of sulfate every year. The sulfates in the atmosphere could impact the ozone layer or turn the sky white.
The study was published in the journal Environmental Research Letters.