A proposal for limited implementation of a sunshade to evaluate the effects of albedo modification on global biogeochemical cycles

Climate change caused by anthropogenic emissions of carbon dioxide and other greenhouse gases threatens to negatively impact human lifestyles across the globe through droughts, floods, and rising sea levels. In spite of these concerns, the amount of carbon dioxide emitted annually has continued to increase in the past decade, from 6.4 Gt of carbon every year in the 1990's to 7.2 Gt in the following decade (Bala, 2009). In addition, a recent study suggests that even if emissions were completely cut, it is too late to prevent temperature and sea level rises. In view of these predictions, more direct methods of maintaining the earth's present climate, such as geoengineering, are a possible solution. Geoengineering is any attempt to purposefully modify the environment on a large scale. However, it is likely that in modifying the earth's systems to solve one problem, geoengineering schemes would create a host of negative unintended consequences. These consequences, which might include pollution, precipitation changes, or declining productivity, have the potential to be more serious than the climate change caused by global warming. Therefore, it is important to thoroughly investigate the side effects of any scheme before implementation. In this paper, I propose to study the unintended effects of a geoengineering pitch authored by Roger Angel of the University of Arizona by partially implementing his plan. Angel (2006) proposes to send small disks into space between the earth and sun to deflect a fraction of the incoming solar radiation and thus cool the earth. To study the effects of this sunshade, I propose to install about 10% of the total number of disks. This limited implementation should affect Earth's climate no more than a volcanic eruption would; at that scale, scientists would be able to measure small changes in precipitation and net primary productivity and extrapolate their findings to predict the effects of a full-scale implementation. Even though geoengineering is an extreme option, it may become one day become the best way to negate the harmful climate changes caused by global warming. Experiments such 3 as the one I propose must take place before implementing a geoengineering plan, and thus the time to conduct these experiments is now, before the day of need.