A Whiter Sky for a Greener World
June 7, 2012 § Leave a comment
In this age of seeking methods to reduce our impact on global warming, some scientists are taking the science in the opposite direction, and using geoengineering to create a greener world by way of non-natural means. What Ben Kravitz and Ken Caldeira, two researchers from the Carnegie Institute for Science, recently came up with was an idea that sounds, at first glance, totally bizarre and kind of frightening–eject aerosols into the atmosphere to reinforce the protective layer over the earth and help reflect the sun’s rays away from the earth’s surface.
This is actually a method that largely mimics natural processes to begin with. When volcanoes erupt, temperatures drop for a period of years, largely due to the ash pumped into the stratosphere, which then serves as a blanket over our planet. This blanket effectively blocks some of the sun’s rays from hitting the earth, and rather reflects them back outwards. Thus the cooling effect that a volcano achieves for several years after a big eruption, we want to artificially simulate by steadily pumping aerosols into the atmosphere and reflecting the sun away from the earth.
Kravitz and Caldeira’s projected plan would only seek to reduce the amount of direct sunlight by 2 but is still considered, according to the study, to be effective. This aerosol injection would potentially offset a carbon concentration twice as large as the amount that existed at pre-Industrial Revolution levels.
And yet perhaps the biggest effect discernible to us would be the color of the sky. the aerosol injections would cause the sky to appear 3 to 5 times whiter than it is now, much like the sky above urban areas is grayer and whiter than the skies hugging a pastoral landscape. Furthermore, sunsets would probably be more intense (color-wise, i.e. pinker, redder), and there would be a more visible glow after the sun had set. While the psychological effects of such a change were not examined in the study, it’s certainly worth taking into consideration before pursuing the project more seriously.
Whether this proposal is in fact a good path to follow is still up in the air. While the aerosols would block sunlight and limit the greenhouse effect in the stratosphere by increasing the planet’s albedo, it would simultaneously make it harder for plants to perform photosynthesis. And whether it’s ethically appropriate to solve anthropogenic problems with more human geoengineering is another question altogether.