A wild idea to combat global warming suggests creating an artificial ring of small particles or spacecrafts around Earth to shade the tropics and moderate climate extremes.
There would be side effects, proponents admit. An effective sunlight-scattering particle ring would illuminate our night sky as much as the full Moon, for example.
And the price tag would knock the socks off even a big-budget agency like NASA: $6 trillion to $200 trillion for the particle approach. Deploying tiny spacecraft would come at a relative bargain: a mere $500 billion tops...
"Reducing solar insolation by 1.6 percent should overcome a 1.75 K [3 degrees Fahrenheit] temperature rise," contends a group led by Jerome Pearson, president of Star Technology and Research, Inc. "This might be accomplished by a variety of terrestrial or space systems."
The power of scattering sunlight has been illustrated naturally, the scientists note. Volcanic eruptions, such as that of Mt. Pinatubo in 1991, pumped aerosols into the atmosphere and cooled the global climate by about a degree. Other researchers have suggested such schemes as adding metallic dust to smoke stacks, to flood the atmosphere and reflect more sunlight back into space.
In the newly outlined approach, reflective particles might come from the mining of Earth, the Moon or asteroids. They'd be put into orbit around the equator. Alternately, tiny micro-spacecraft could be deployed with reflective umbrellas.
A ring created by a batch of either "shades the tropics primarily, providing maximum effectiveness in cooling the warmest parts of our planet," the scientists write. An early version of their idea was presented but not widely noticed in 2002.
As always, the comments section over at FuturePundit is extremely lively, lots of interesting ideas being batted around -
- and in fact one of the participants, the Engineer-Poet, just posted a rather stunning 'outside-the-box' solution of his own - carbon negative energy systems that would actually reduce the amount of CO2 in the atmosphere:
Thermochemical reduction of zinc oxide to metal using biomass as the carbon source captures atmospheric carbon and can convert it to a stream ready for permanent disposal. Possible biomass sources include biomass crops, byproducts from food crops, forestry waste and post-consumer waste materials. At a biomass consumption rate of 600 million dry tons per year, the system would supply roughly 317 gigawatts. This would supply 72% of US electric needs or 1.8 times US transportation energy needs, while sequestering 880 million tons of carbon dioxide every year. World-wide use of biomass-fed thermochemical zinc systems could reduce atmospheric concentrations of carbon dioxide by about 0.44 parts per million (by volume) per year; acting alone, such systems could restore the global atmospheric CO2 concentration to its pre-industrial level in about 225 years. Expansion of thermochemical zinc systems and their biomass feeds to allow increased electric production would hasten this process. Both the effluent CO2 stream and the stored CO2 could be returned to the atmosphere at any time should that be desirable. This spells the end of air pollution and human control of global warming. Restore the atmosphere?
Engineer the climate? If we want to, we can do it.
It's possible - see his earlier post Miracle Metal, which looks at some new zinc-centric research that inspired this post. Of course, we'd still have to decide exactly what kind of climate we'd want to engineer, which could be pretty contentious I'm sure, and then we'd have to figure out exactly how much CO2 is linked to how much global warming, which we don't have a very firm grasp on at all yet. But - it's possible.