If It Comes to It...


If the world must resort to geoengineering as a means of mitigating dangerous effects of anthropogenic climate change, how well would it understand what it is getting itself into?

Since Nobel Prize-winning physicist Paul Crutzen, formerly a researcher at Scripps Institution of Oceanography, UC San Diego, lent credence to the idea of conducting large-scale efforts to influence Earth's climate systems in a 2006 essay in the journal Climatic Change, research centers have explored the feasibility of various techniques. While the logistics of mitigation efforts and their ethical considerations have been widely discussed, a basic analysis of how geoengineering projects could affect ecosystems has lagged, said Lynn Russell, a professor of atmospheric chemistry at Scripps.

At the American Geophysical Union Fall Meeting (U44B-03· Thursday, Dec. 8, 4:30-4:45 p.m. · Moscone South Room 104), Russell and others will discuss a report on two broad categories of geoengineering strategies that have recently been advanced. The panelists were all participants in a geoengineering workshop hosted by Scripps in January 2011 from which the report was produced. The panel will also discuss what it will take to assess the feasibility of mitigation methods, especially in regard to their potential to benefit or damage ecosystems.

"Because research on this topic is just beginning, our report summarizes what is known, but also suggests the type of research that will be necessary to answer the questions we posed," said the panelists.

Sunlight reflection methods are one of the two categories. They generally involve attempts to reflect more sunlight back into space, therefore diverting that heat energy away from Earth's surface. The workshop report has assessed the relative merits and risks of sunlight reflection methods, one of which involves reflective aerosols introduced into the upper reaches of the atmosphere. Such methods could entail efforts that require a great deal of manpower from multiple countries.

Russell notes, as an example of what could go wrong, that if such efforts were initiated and then stopped for whatever reason, the sudden reversion to less sun reflection could do more harm than good to ecosystems.

"If you stopped the efforts, climate change would occur much more rapidly. There would be less time for ecosystems to react," said Russell. "The hope would be that the report would make the community aware of these open questions and that people pursue these questions individually and collaboratively," Russell added.

The other category of geoengineering considered by Russell and her colleagues, carbon dioxide removal, requires a similar thinking-through of potential unwanted catastrophic consequences.

The publication of Crutzen's essay is cited by many as the moment when geoengineering became a legitimate topic, said co-panelist Margaret Leinen, executive director of the Harbor Branch Oceanographic Institute in Fort Pierce, Fla. Leinen has assessed a geoengineering technique that accelerates carbon dioxide removal by fertilizing oceans with iron or other micronutrients for phytoplankton, a technique widely discussed, though evidence of its consequences remains fraught with uncertainty. She noted that geoengineering has been the subject of three Congressional hearings and discussed in Britain's parliament since the essay appeared. As serious consideration spreads, however, workshops like that held at Scripps are necessary to ensure that ecosystem risk/reward analyses take place as these strategies are studied, she said.

"People have been talking about very substantial geoengineering field tests. We're saying that as you consider all of this, you need to include in your planning ways to study ecological consequences at the same time that you study the techniques," Leinen said.

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