CHICHELEY, U.K.—The Intergovernmental Panel on Climate Change suggests temperatures could rise by as much as 6.4 C by 2100, swelling seas and disrupting climate patterns.
Now, scientists are seeking ways to alter the sun’s effect by employing technologies that would reflect its heat back into the atmosphere.
The Wood Hole research centre in Massachusetts has also looked at fertilizing oceans with iron to grow CO2-eating plankton.
Scientists at the U.S National Centre for Atmospheric Research are currently developing a test of brightening ocean clouds with sea-salt particles to reflect the sun.
And while those techniques are necessarily limited in scale and unable to alter planet-wide warming, one idea has shown promising potential.
“By most accounts, the leading contender is stratospheric aerosol particles,” said climatologist John Shepherd of Britain’s Southampton University.
Stratospheric aerosol particles are sun reflecting sulphates spewed onto the lower stratosphere from an aircraft. The technology is very similar to the sulphur dioxide emitted by the eruption of a volcano in the Philippines in 1991 that is said to have cooled the earth by 0.5 C for about a year.
Engineers from the University of Bristol, England, plan to test the feasibility of feeding sulphates into the atmosphere via a hose attached to a tethered balloon.
The engineers have stressed that any sun-blocking solar radiation management (SRM) technique has to be accompanied by sharp reductions in carbon dioxide emissions on the ground and some form of carbon dioxide removal from a chemical mechanical process that would suck gas out of the air and neutralize it.
If not, the stratospheric sulphate layer would have to be built up indefinitely to counter the growing greenhouse effect of accumulating carbon dioxide.
And if that SRM operation shut down for any reason, temperatures on Earth would shoot upward.