Geoengineering is not a last resort, but the next necessary step to recalibrate the Earth's climate unless carbon emissions are significantly reduced in the near future, the Royal Society, the U.K.'s national academy of sciences, announced Tuesday.>
"It is an unpalatable truth that unless we can succeed in greatly reducing CO2 emissions we are headed for a very uncomfortable and challenging climate future, and geoengineering will be the only option left to limit further temperature increases," John Shepherd, chair of the Royal Society's geoengineering study and a professor of Earth system science at the University of Southampton, said on behalf of the group.
The report "Geoengineering the climate: Science, governance and uncertainty" (PDF) urged carbon emissions reduction as the primary means of halting climate change. But it looked at geoengineering--engineering the environment on a large scale to purposely manipulate the world's climate--very seriously.
In past years, geoengineering has been thought of an as option of last resort, but the Royal Society asserted that some of the safer geoengineering techniques, like aggressively planting forests, could be implemented currently in conjunction with carbon reduction efforts.
Since geoengineering has the potential to affect people on a global scale, the group further recommended that an international organization like the U.N. Commission for Sustainable Development begin developing policies and a means for resolving anticipated geoengineering political conflicts.
"Assuming that acceptable standards for effectiveness, safety, public acceptance and cost were established, why should appropriate geoengineering options not be added to the portfolio of options that society will need and may wish to use to combat the challenges posed by climate change?" said the report.
With that in mind the group evaluated the safety, expense, effectiveness, and quickness of deployment for projects falling under two main classes of geoengineering: carbon dioxide removal (CDR) and solar-radiation management (SRM).
CDR, efforts to remove greenhouse gases from the atmosphere, included things like afforestation, encouraging plankton growth, and carbon capture and storage in the form of burying carbon-rich biomass or using biochar for fuel.
The SRM suggestions for manipulating the Earth so that it absorbs less solar radiation included more seemingly far-out options like painting all roofs white to reflect sunlight, placing thousands of space mirrors in near-Earth orbits to reflect sunlight, and spraying aerosols into the stratosphere.
The group said it generally favored CDR projects over SRM because they involved processes closer to natural occurrences, while the side effects of SRM projects are unknown and therefore more dangerous.