Image courtesy of NASA
Talk about a lose-lose proposition: According to a new article published in the journal Science, a proposed geo-engineering scheme to inject sulfate particles into the stratosphere to mitigate the impact of global warming could damage the ozone layer. Yet another article, published in the journal Geophysical Research Letters, has determined that allowing for a complete recovery of the ozone layer could actually intensify global warming's impact in the Southern Hemisphere.Though it probably comes as a surprise to no one that a scheme that would've involved using large balloons or aircraft to pump sulfur particles high into the stratosphere -- in an attempt to replicate the effect of a volcanic eruption -- would have some negative repercussions, few had expected that a full recovery of the ozone layer would also create some difficulties.
While the science behind the sulfur particle proposal is actually fairly sound in principle -- the sulfur particles ejected into the stratosphere, like the ash and sulfur dioxide released by volcanoes during eruptions, would reduce the Earth's absorption of sunlight, prompting a cooling effect -- its secondary effects, including the promotion of chemical reactions that would lead to the destruction of the ozone layer, seriously undermine any perceived benefits. Indeed, Simone Tilmes, the lead author and an atmospheric scientist at the National Center for Atmospheric Research (NCAR), believes the proposal would push back almost 2 decades' worth of efforts to repair the planet's ozone layer.
That isn't to say that this study should necessarily drive the final nail in geo-engineering's coffin; as with many such schemes, there's always a flip side to inaction. In this case, as Phil Berardelli goes on to report, another study, led by University of Colorado, Boulder, atmospheric scientist Judith Perlwitz, a full restoration of the Antarctic ozone hole could greatly intensify the impact of global warming in the Southern Hemisphere -- causing temperatures in the Antarctic stratosphere to rise by as much as 9°C by century's end. Such a huge increase would drive temperature increases worldwide.
Given the controversy that surrounds geo-engineering, it's probably best that we see more studies like these done before we take any drastic action. Commercial ventures that hope to pursue such schemes to capitalize on the growing carbon market should wait until more definitive evidence is provided by scientists.
Via ::ScienceNOW: Ozone: Friend or Foe? (news website)