New Mexico: US geoengineers to spray sun-reflecting chemicals from balloon

Two Harvard engineers are to spray sun-reflecting chemical particles into the atmosphere to artificially cool the planet, using a balloon flying 80,000 feet over Fort Sumner, New Mexico. The field experiment in solar geoengineering aims to ultimately create a technology to replicate the observed effects of volcanoes that spew sulphates into the stratosphere, using sulphate aerosols to bounce sunlight back to space and decrease the temperature of the Earth. David Keith, one of the investigators, has argued that solar geoengineering could be an inexpensive method to slow down global warming, but other scientists warn that it could have unpredictable, disastrous consequences for the Earth's weather systems and food supplies. Environmental groups fear that the push to make geoengineering a "plan B" for climate change will undermine efforts to reduce carbon emissions. Keith, who manages a multimillion dollar geoengineering research fund provided by Microsoft founder Bill Gates, previously commissioned a study by a US aerospace company that made the case for the feasibility of large-scale deployment of solar geoengineering technologies. His US experiment, conducted with American James Anderson, will take place within a year and involve the release of tens or hundreds of kilograms of particles to measure the impacts on ozone chemistry, and to test ways to make sulphate aerosols the appropriate size. Since it is impossible to simulate the complexity of the stratosphere in a laboratory, Keith says the experiment will provide an opportunity to improve models of how the ozone layer could be altered by much larger-scale sulphate spraying...more

Scientists respond to this article

Recent media claims (see: http://www.guardian.co.uk/environment/2012/jul/17/us-geoengineers-spray-sun-balloon) that we have plans “... to spray thousands of tonnes of sun-reflecting chemical particles into the stratosphere…” in attempt to combat global climate change, are incorrect.
Instead, we are addressing the growing pressure to “geo-engineer” the climate by exploring techniques to demonstrate the effects of such proposals without adding the proposed sulfate species (which are naturally occurring in the Earth’s lower stratosphere) in any amount that could possibly alter the background stratosphere. The Guardian article that first reported such claims (and subsequent articles mentioning the piece) was never fact-checked in even the most superficial sense with either one of us. A related New York Times article (http://green.blogs.nytimes.com/2012/07/17/trial-balloon-a-tiny-geoengineering-experiment/) provides a more balanced approach and a piece in Business Insider also provides clarity (http://www.businessinsider.com/david-keith-says-guardian-story-is-substantially-fabricated-2012-7).
In summary, we have been and are currently exploring possible new strategies for interrogating the stratospheric system without affecting the background stratosphere in any quantitative way. To date, we have not written any proposal to actually do so. We want to be absolutely clear that that we have no plans to implement a geoengineering field study to release “thousands of tonnes of sun-reflecting chemical particles into the atmosphere to artificially cool the planet, using a balloon flying 80,000 feet over Fort Sumner, New Mexico.”...