[clim] Algae to the rescue?

[RAU greg]

Science 7 May 2010:
Vol. 328. no. 5979, pp. 690 - 691
DOI: 10.1126/science.328.5979.690-a

Letters

Shifting the Debate on Geoengineering

As discussed in the recent Policy Forum "The politics of geoengineering" (J. J. Blackstock and J. C. S. Long, 29 January, p. 527), there is growing recognition that avoiding dangerous climate change during the 21st century may require society to adopt geoengineering technologies to supplement CO2 emission reduction efforts. Unfortunately, despite the essential role that CO2 removal (CDR) and solar radiation management (SRM) technologies may play in reducing the risks of dangerous climate change, discussions of the necessary research and development [including the Policy Forum and others (1, 2)] frequently turn into debates about the environmental costs and benefits of SRM. A more productive approach would shift the debate to comparing the relative costs and benefits of CDR and SRM.

CDR approaches are frequently discounted because, as Blackstock and Long explain, "technical challenges and large uncertainties [surround] large-scale CDR deployment." Although this may be true for human-built systems that capture CO2 from air at ambient concentrations, there are other technologies based on biological carbon fixation that could be fast-tracked for rapid deployment during the next few decades (3). Most major international energy corporations are investing in algal-based biofuel technologies because of the tremendous production potential of algae relative to terrestrial energy crops (4). Commercial-scale production of algal biofuels will begin during the next 5 years, and rapid scaling up can be expected afterward if the economic incentives are favorable. However, becoming carbon negative will require society to develop plans for retrofitting existing coal-fired power plants and building future ones so that they can burn algal biomass and capture the emitted CO2 for subsequent sequestration. The basic technologies described here are not novel; rather, I am proposing a conceptual rearrangement that may enable society to transition more gracefully from fossil to modern carbon fuel sources while simultaneously reducing CO2 levels in the atmosphere and ocean.

Charles H. Greene

E-mail: ch...@cornell.edu

Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14853, USA.

References

• 1. A. Robock et al., Science 327, 530 (2010).[Abstract/Free Full Text]
• 2. D. W. Keith, E. Parson, M. G. Morgan, Nature 463, 426 (2010).[CrossRef][Web of Science][Medline]
• 3. D. W. Keith, M. Ha-Duong, J. K. Stollaroff, Climat. Change 74, 17 (2006).[CrossRef]
• 4. M. E. Huntley, D. G. Redalje, Mitigation Adapt. Strategies Global Change 12, 573 (2007).[CrossRef]

 

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