Plan B for Climate Change

If the governments of the world can’t get their act together and cut greenhouse gas emissions soon, the world will need plan B. That backup plan, according to a report this week from the Royal Society, is for science to help save the day through geoengineering. This includes technologies that suck carbon dioxide out of the air. Or perhaps shading the Earth’s surface from the sun’s rays by spewing aerosols into the stratosphere. Slashing emissions is the number one way to address climate change, the Society reaffirms. But if political talks on reducing emissions get stuck – and they very well might – geoengineering will be the only game left in town to fend off serious global warming. Every geoengineering technique carries risks for people and the planet, the report warns. But some are better than others. Technologies that strip carbon dioxide out of the air get the best marks in the report. There’s a catch, of course. So far, no method except the planting of trees can lock away atmospheric CO2 cost-effectively. And only so much land on Earth can grow trees. Ranking next among geoengineering techniques according to the Society, are technologies to block sunlight, such as giant, space-based mirrors. These could lower surface temperatures quickly. But they won’t do a darn thing about other key effects of a rising CO2 level -- notably the increasing acidity of oceans and the havoc it would wreak on ocean ecosystems. Other geoengineering schemes got a “lower potential” rating from the Society. One is adding fertilizer to the ocean to stimulate algal growth -- in hopes of increasing photosynthesis to extract more CO2 out of the air. Not proven effective, the report says of this technology, and “high potential for unintended and undesirable ecological side effects” Some geoengineering ideas are duds, the report finds, such as installing reflectors in the desert in an attempt to mirror light back into space. The Society smacked down an idea touted by U.S. Energy Secretary Stephen Chu – painting roofs white. While painting roofs white can save on energy for air conditioning, adopting them for geoengineering purposes, like deploying reflectors in deserts, is, the report says, ineffective and expensive.

Author: Cheryl Hogue

Share This Post On


  1. As a biophysicist studying the global warming issue since Al Gore’s film, I have to say I am unconvinced that ocean buffering capacity is anywhere near being threatened by human CO2 production.

  2. It makes sense that ground-level reflective material would not really help – after all, the light and heat bouncing off of it would still just be trapped by the greenhouse gases in the atmosphere. What I would suggest would be giant balloons made of Mylar or similar material, hovering just outside the heat-trapping zone. The sides of the balloons facing Earth could even be used to display corporate sponsorships, thus helping to defray the cost. Or maybe the balloons could serve as solar concentrators, and we could capture electricity that way. Hmmm… time to round up some venture capital!

  3. Some of the more desperate geoengineering ideas that I have heard, such as the creation of massive sulfate aerosols in the stratosphere to reflect incoming sunlight spaceward, elicit a very nervous smile on my face. Interesting yes, but quite an experiment. It’s kind of like suggesting starting a fire in your attic to put out a fire in your basement, without evacuating the house.

  4. Andrew Maynard over at 2020 Science has some additional discussion on the report that’s worth reading.
    @Melody- those balloons would have to be enormous for anyone to see the logos… passing aircraft, perhaps? Do we have balloons of any kinds that stay inflated for any decent period of time? Whatever we inflate them with had better be pretty harmless, because it’s inevitably going to leak out.

  5. Make a giant light reflector between the Earth and the sun?

  6. Emissions have resulted in a Polar Albedo that resembles a less than paler shade of white.
    Clearly painting the Poles to reflect more efficiently is the answer.
    The best reflector is fresh snow.