Is Aerosol Engineering Ethically Preferable to other Climate Change Mitigation Strategies.pdf

Is Aerosol Geoengineering Ethically Preferable to Other Climate Change Strategies?
Pre-Print Version
Toby Svoboda (Assistant Professor of Philosophy, Fairfield University)
Forthcoming in Ethics & the Environment (2012), Indiana University Press
Introduction.
In this paper, I address the question of whether aerosol geoengineering (AG) ought to be
deployed as a response to climate change. First, I distinguish AG from emissions mitigation,
adaptation, and other geoengineering strategies. Second, I discuss advantages and disadvantages
of AG, including its potential to result in substantial harm to some persons. Third, I critique three
arguments against AG deployment, suggesting reasons why these arguments should be rejected.
Fourth, I consider an argument that we ought to adopt that response to climate change which
would result in the least net harm to persons. I suggest that under certain conditions , such as a
climate emergency scenario, the least harmful climate change strategy could involve deployment
of AG. The implication is that, despite the risks of harm associated with it, in certain situations
AG could be (or be part of) a climate change strategy that is ethically preferable to other
available strategies.
Mitigation, Adaptation, Geoengineering.
Climate change could result in severe harm for some persons
1
through various impacts,
including sea-level rise, ocean acidification, droughts, and an increase in the frequency of severe
weather events (IPCC 2007). Partly because anthropogenic emissions of greenhouse gases are
the driving forces behind these potentially harmful impacts, climate change raises a number of

2
ethical issue (Singer 2004, 14-50; Gardiner 2004). But what ought to be done to reduce or, if
feasible, eliminate the harm that climate change threatens to cause? Often discussed responses
include mitigating greenhouse gas emissions (Nordhaus 2001) and adapting to the impacts of
climate change (Lobell et al. 2008). Another option is geoengineering, or the intentional, large-
scale manipulation of the Earth’s environment (Keith 2001). In recent years, a growing number
of scientists has called for more research on geoengineering as a potential response to climate
change (Crutzen 2006; Shepherd 2009; MacCracken 2006; Keith, Parson, and Morgan 2010).
Geoengineering techniques can be divided into two categories. First, carbon dioxide
(CO
2
) removal would reduce the quantity of greenhouse gases in the atmosphere, either by
trapping emissions at their sources or by drawing CO
2
directly out of the atmosphere, such as by
using air scrubbers or growing large phytoplankton blooms in the oceans in order to absorb
atmospheric CO
2
(Shepherd 2009, 9-23). Once captured, the CO
2
could be sequestered
underground or in the deep ocean. If it works as planned, this would cancel the warming effect
the sequestered CO
2
would otherwise have had in the atmosphere. However, the costs of some
forms of CO
2
removal, such as capturing it at its source and sequestering it, are currently
projected to be quite high (Shepherd 2009, table 5.1). Further, the effectiveness of some forms of
CO
2