“There’s no practical way for emissions reductions to reduce global temperatures this century.”
This eye-opening statement was made by Dr. Ken Caldeira at the Institute for Sustainable Energy, Environment and Economy at the University of Calgary’s 2009-2010 Distinguished Speaker Series in early March this year. Caldeira heads up a lab at the Carnegie Institution for Science at Stanford University and he’s a world leader in the study of geoengineering—intervention in the climate system in order to reduce climate change risk. Does this mean we should be giving up on all our serious attempts at greenhouse gas reductions like carbon capture and storage, if it’s all going to be in vain?
Hardly. But Caldeira, who was dubbed “Hero Scientist of 2008” by New Scientist magazine, is no fringe researcher. He’s been called upon by the UN’s Intergovernmental Panel on Climate Change, the US Congress and the British Parliament. He has little confidence that humans can or will accomplish the massive GHG reductions needed to avoid environmental catastrophes like sea level rises and severe droughts. So although he wouldn’t want to see it happen, we may just have to intervene at some point in the near future. He has modeled some of the techniques to cool the planet: space reflectors, injecting aerosols into the stratosphere, cloud albedo (injecting seed nuclei over the oceans) and surface albedo (e.g. plastic over the deserts or painting urban roofs white).
His models revealed most to be impractical. The exception was stratospheric aerosol injection; he based the idea on the 0.5 degree C cooling effect of the 1991 Pinatubo volcano in the Philippines and how his model demonstrated improved plant growths. Problems with this option he said were the unknowns and the ethical and moral decisions like who do we allow increased damage to? His “equity and damage reduction functions for temperature and precipitation” opened a whole new area of ethics, pitching benefits to the western world against impacts in the developing world. And not lost were “unexpected outcomes” when humans tinker, like the historic cane toad and rabbit episodes in Australia.
The options are in their infancy, but how much longer can they stay there?