Summary: SUMMARY: In this program we talk with one of the world's top experts on geoeningeering to cool the planet, Harvard's Dr. David Keith. Then from the UK, Dr. Rose Cairns investigates the internet phenomenon of chemtrails, the belief that aircraft are already poisoning the sky. Is it an expression of public fears about geoengineering? Radio Ecoshock 150318 I'm Alex Smith. Let's go. Download or listen to this Radio Ecoshock show in CD Quality (56 MB) or Lo-Fi (14 MB) Or listen on Soundcloud right now! DR. DAVID KEITH ON CLIMATE ENGINEERING: SOLAR RADIATION MANAGEMENT When people talk about geoengineering, for or against, one name keeps coming up. For over 20 years, scientist David Keith has kept open the door for discussion and research on climate modification. At Harvard University, David is a Professor in the School of Engineering and Applied Sciences. He's also a Professor of Public Policy at the prestigious Harvard Kennedy School. Dr. Keith wins awards and criticism for talking about technology to stave off the worst of climate change. Like most scientists, David Keith works hard to get a society with fewer greenhouse gas emissions. He also has a Calgary-based company trying to remove CO2 from the air. But today we pick David's brain on technology to artificially cool the planet, by blocking out some of the sun's rays. It's called Solar Radiation Management, or SRM. First David describes how spraying sulfur into the upper atmosphere would work. Essentially, if the particles are small, they stay up there for long periods of time, reflecting some of the sun's rays back into space. The sulfur droplets would be sprayed from an airplane, about 20 kilometers (12 miles) high in the atmosphere. Scientists in the Arctic Methane Emergency Group have already called for regional SRM in the Arctic. They hope to preserve what is left of Arctic Sea ice, to slow glacial melt, and to prevent large-scale releases of methane from the clathrates or thawing permafrost. I ask David what he thinks of this proposal. David Keith says the concept of regional Solar Radiation Management is meaningless. The particles will spread down over at least most of the Northern Hemisphere, rather than staying over the Arctic. Due to the way this planet's air mixes, the sulfur particles would not enter the Southern Hemisphere to any large degree. So trying to cool the Arctic means repeatedly recharging the sulfur spraying over the Arctic, and essentially cooling the whole Northern Hemisphere, with expected and unknown side effects for crops in Canada, the United States, Europe and Scandinavia, and Russia. Not all scientists agree that regional cooling is impossible. Next week I'll talk with Dr. Alan Robock. His group ran models looking at what would happen if someone dumped about 5 million tons of sulfur over the Arctic. We'll find those results next week. U of Ottawa PHD student Paul Beckwith also thinks Arctic cooling could work. We just don't know for sure. That is one reason Dr. Keith says more research is needed into SRM, and he supports the recent call for that research by the U.S. National Academy of Sciences. However the Academy support does not translate into real funding. That probably has to come from governments. That isn't happening yet. David says there is a political and social taboo about even researching geoengineering. Some groups, like the ETC Group, worry if the public thinks there is a quick technical fix, then we won't change away from burning fossil fuels. One of the key unknowns is the impact of SRM on rainfall. It may reduce rainfall in some areas, but may also reduce extreme rainfall events. Again, we'll hear more about that next week with Dr. Robock. But David Keith says the idea that SRM will cause drought is a "false claim". Don't get the idea that David Keith is a total supporter of geoengineering. He worries about things like damage to the ozone layer, and many other affects. Really Keith is not sure SRM should ever be used. He is sure
