If reducing carbon emissions can’t stop global warming—and so far, it isn’t—why not throw paint at the problem?
That’s the provocative—and totally serious—proposition being floated by UK researchers, who are studying whether using balloons “to lift and disperse stratospheric aerosols” could “scatter the sun’s light back into space” and “work as a ‘plan B’ for climate remediation.”
Wikimedia Commons / Hughhunt
|The UK’s Stratospheric Particle Injection for Climate Engineering (SPICE) project employs a Solar Radiation Management technology using water. The technology is similar to one that is being explored using titanium dioxide.|
So writes Peter Davidson, a noted chemical engineer, in “Up and away!” in this month’s tce magazine.
Davidson, a fellow of IChemE and the Royal Academy of Engineering and a former innovation advisor to government, says he and other researchers are looking at such a geoengineering strategy to climate change.
And he, for one, thinks it’s an idea worth pursuing.
“Atmospheric carbon dioxide levels are higher than they have been in the last 400,000 years, as a result of mankind producing CO2 at an ever-increasing rate,” Davidson reports.
There is “broad consensus” by climate scientists that the current trend will eventually have “dire consequences” in the form of more severe and more frequent droughts, hurricanes and tornadoes and rising sea levels, he adds.
CO removal is possible but would take too long, Davidson says, leaving scientists now searching for a “Plan B” to be “switched on quickly if matters go badly wrong.”
Blasting paint particles into outer space, he contends, could be that Plan B.
What Volcanoes Teach
It’s not so crazy. Dispatching particles into the atmosphere is a type of “solar radiation management” that could scatter the sun’s rays back into space, rather than having them fry terra firma, Davidson explains.
Davidson cites research by Nobel laureate Paul Crutzen, who suggested that the effect would be similar to that of a large volcanic eruption, which has been found to provide global cooling “of up to 1°C for a few years.”
|Peter Davidson is seeking a patent for his climate change technology.|
For example, Davidson says, the 1991 eruption of Mount Pinatubo in the Philippines threw 20 million tons of sulfur dioxide into the stratosphere, soon creating a sulphuric acid aerosol that lowered mean global temperatures by about 0.5°C for two years.
But because no one wants a poisoned atmosphere that smells like rotten eggs, Davidson has turned to titanium dioxide.
Not only is the popular paint pigment safer than SO2, but it is in wide supply and, thanks to “well-established coating technologies,” its light-scattering properties have been well established and it can be tailored to a wide variety of applications. TiO2 is highly refractive, stable in air and non-toxic, Davidson notes.
Davidson says his consulting firm, Davidson Technology, is seeking a patent on a process that would employ titanium dioxide in some sort of coating form for possible use in the stratosphere.
(The patent, which was not detailed, has become embroiled in a dispute with other UK researchers who are working on a similar system, reports said this week.)
Davidson figures it would take about three million tons of TiO2 particles to get the job done. “If the particles remain in the stratosphere for two years, then 1.5m t/y must be lofted, equivalent to an annual average coating of 1 nm on the earth’s surface,” he writes.
“Such coatings would need to be stable for several years under the harsh UV illumination in the stratosphere,” he notes. “Hydrophobicity may also help to avoid ice nucleation on the TiO2 particles.”
OK, but once you have the coating, how do you get it into space? Davidson details ongoing research into delivery systems that use a tethered weather-type balloon equipped with a pump and pressurized pipe.
One of the scientists behind that research is Nathan Myhrvold, former CTO at Microsoft, who entered college when he was 14 and had a doctorate in theoretical and mathematical physics by the time he was 23. Myhrvold has patented a balloon system that he says could be used to “dim the sun.”
|Nathan Myhrvold has patented a balloon system that he says could be used to “dim the sun.”|
Davidson estimates the cost of materials at $4.8 billion a year and development at about $3 million a year initially, increasing to perhaps $16 million a year in five years. With 20 years for R&D, and another 15 years for implementation, it’s a doable project, Davidson says.
Making it Work
Of course, as a government veteran, Davidson is also aware that the science may be the least of the project’s challenges.
Indeed, just since his article was published, a field trial for a similar geoengineering experiment (that would have used water, rather than TiO2) was cancelled amid questions over Davidson’s patent application.
The trial was to have been the next step for the Stratospheric Particle Injection for Climate Engineering (SPICE) project, a UK-government-funded collaboration of several universities.
“Technical issues are likely to be more manageable than political, legal, social and ethical considerations: who should control the ‘thermostat,’ how do you prevent being sued by every farmer in the world with a poor crop?” Davidson writes.
“Arbitrating who would be the winners and losers is a huge ethical challenge.”