Cooling back the Earth: possible ? Reasonable ?
Geoengineering is a solution. But is it realistic ? Even possible ? Since these solution have been much talked about recently, this article will present you the main solutions.
From building a space sunshade to emitting tons of sulphur in our atmosphere or even artificial trees, we are nearer to science fiction than pure sciences.
Andrew Revkin on Dot Earth proposed a year ago a good introduction:
The trajectories for emissions of carbon dioxide as the world’s industrial and industrializing countries boost coal burning are clearly going to be tough to turn around, whether through caps on emissions or efforts to improve non-polluting energy technologies. And big hurdles remain before there will be any large-scale capturing of carbon dioxide to pump it underground or elsewhere for safekeeping.
That’s why a growing number of scientists, including Nobel Prize winners and Ralph J. Cicerone, the president of the National Academy of Sciences, have pushed for intensified study of ways to artificially nudge the planet’s thermostat downward — at the very least as a “Plan C” should warming kick into high gear.
TreeHugger presented a good overview of the main solutions:
Spray Sulfate Aerosols Into The Atmosphere
Though cited by a number of reports as being rather risky due to potential unintended consequences, the idea behind spraying sulfur particles into the atmosphere goes something like this: By using large balloons or aircraft to put more sulfur particles into the stratosphere, you could reduce the Earth’s absorption of of sunlight and prompt planetary cooling. Similar to what happens when volcanoes erupt and put ash and sulfur into the air.
Trap CO2 in Carbon Scrubbers
Perhaps two years from being manufactured, researchers at Columbia University say that soon they may have a working carbon scrubber which could take one ton of CO2 out of the air per day. Small than a standard shipping container in size, and about $200,000 in price, these carbon scrubbers trap CO2 entering them on an ion exchange resin.
Fertilizing Trees With Nitrogen
The idea here is said easily enough: Fertilize trees with nitrogen to stimulate their ability to absorb more carbon dioxide and, by increasing their albedo, reflect more solar radiation back into space.
Dump Limestone into the Oceans
This one’s a bit of a ringer in the group, in that rather than combatting global warming directly, plans for dumping powdered limestone in the ocean would mainly address anticipated increasing ocean acidity. Due to these changes in pH levels in the world’s oceans brought about by climate change, most of the planet’s coral reefs could be wiped out, with devastating consequences for marine life and the humans which depend on it. But, by adding large amounts of powdered limestone to the sea these changes in water acidity could be checked–with the added bonus of increasing carbon sequestration as well.
Ocean Iron Fertilization
Essentially mimicking natural processes, ocean iron fertilization hopes to stimulate the rate of photosynthesis in phyto plankton, increasing the amount of carbon dioxide which is absorbed, and creating essentially an artificial algae bloom. The thing is that the CO2 absorbed has to sink to sufficient depth (a couple of miles) so that it won’t simply be circulated back up into the atmosphere.
Other solutions might be envisaged :
To me, any geoengineering solutions should come last, once we have done our utmost in decreasing our energy consumption and overall pollution. And you, what do you think ?