PRESIDENT'S LETTER

(Note: A production error resulted in the duplication of a sentence in the printed version of the July/August President’s Letter. The corrected version is online at http://www.aspb.org/newsletter/julaug07/01pl34_4.cfm.)

Rick Amasino

The Energy Pie

I sense that during the past year the public attitude has shifted appreciably toward acceptance of the scientific consensus on the effect of human activity on climate. Accordingly, the media has become less willing to provide a forum to those who deny the scientific consensus; providing such a forum would no longer be good for their ratings. I did not expect this shift to happen so quickly. Now that acceptance is less of an issue, it is incumbent on members of the scientific community to help foster public understanding of the details of energy and climate issues so that as a society we can make more informed decisions.

Although my own experience with public understanding of energy and climate issues is limited, it does indicate that there is much that ASPB members could contribute. For example, a friend recently noted that the United States could make a major contribution to mitigating climate change if the majority of U.S. residents shifted to driving completely electric vehicles. I asked if she had considered two questions. What fraction of total CO₂ emissions in the United States emanate from the transportation sector? (Answer: ~30%.) What percent of the electricity generated in the United States is derived from fossil fuels? (Answer: ~70%.) As ASPB members know, if a greater portion of the energy for the transportation sector were obtained from the electric grid, additional electrical power plants would need to be built, and those additional plants would likely burn fossil fuels.

Shifting to electric vehicles could have a substantial impact on the rate of atmospheric CO₂ increase if the CO₂ produced by fossil fuel burning power plants was captured and sequestered (it will probably be impractical to capture CO₂ from individual automobiles). The possibility that CO₂ capturing technology may be required in future power plants appears to be part of the motivation behind a recent surge in power plant construction; certain investors are betting that plants built soon may be “grandfathered” from possible future regulations such as a requirement for CO₂-capturing devices (1).

Another example: I was recently asked for my opinion about the following carbon offsetting program from The Conservation Fund (2).

Go Zero with The Conservation Fund
Climate change has become the biggest environmental issue of this century. But while most Americans agree that we must do something, the challenge seems too great, too complicated for any one of us to make a difference—until now.

The Conservation Fund has launched a new program called Carbon Zero that makes it easy and affordable for individuals, corporations or even entire communities to Go Zero by measuring and then offsetting their carbon emissions—simply by planting trees.

The Conservation Fund site states that a tree can sequester, on average over a 100-year lifespan, a little over 20 lbs of CO₂ per year and that producing and combusting a gallon of gasoline releases approximately 20 lbs of CO₂. The site also notes that, to date, the Fund has planted 9 million trees. But one detail is needed to appreciate the magnitude of what would be required to offset the carbon emissions of, for example, just the automobile component of the U.S. transportation sector. Every year, U.S. drivers consume at least 150 billion gallons of gasoline (3). Thus, to offset the tailpipe emissions of U.S. drivers, 150 billion trees would need to be planted where forests do not already exist.

Is there sufficient land in the United States capable of supporting additional forests that collectively contain 150 billion trees? If 150 billion additional trees were grown in the United States, would this impact food and/or biofuel production? If we rely on other countries to sequester our CO₂ by planting trees, will they be able to sequester their own CO₂? Can we guarantee that such land will remain forested? Finally, as forests mature, their rate of CO₂ capture will decrease unless their biomass can be harvested and sequestered.

I recognize that organizations that restore or maintain forests can have an important role to play in mitigating climate change. Many small steps can collectively be significant, there are many tree-planting and forest-maintaining organizations in addition to The Conservation Fund, and forests are a critical component of the current global carbon balance. Indeed, in the past decade, clearing of tropical forests accounted for about 20% of the anthropogenic CO₂ increase in our atmosphere (4), an amount similar to that released by total fossil fuel use in the United States (not just the transportation sector). Much of the tropics remains forested, so there is an enormous pool of sequestered carbon in these ecosystems that will continue to be released if deforestation continues.

I am concerned, however, that the purchase of carbon offsets could lead to a sense of complacency among those who do not appreciate that there are not enough forest-based carbon offsets to offset all or even most of the current CO₂ emissions. Indeed, I have encountered several stories in the mainstream media favorably portraying individuals whose justification for their well-above-average CO₂ emissions is that they have purchased carbon offsets. Although most media reports are favorable, the sale of carbon offsets has been compared to the practice, common during the Middle Ages, of selling indulgences to offset sins (5).

ASPB members recognize that, at present, multiple approaches will be required to reduce greenhouse gas emissions to levels that are thought to be necessary to prevent major disruptions in climate (6). It is important that we communicate this point to the public because much of the media coverage, as well as some of the political rhetoric, can give the false impression that there are a few simple routes to stabilizing atmospheric CO₂ levels such as tree planting, biomass conversion, and reinstating fuel efficiency standards for automobiles.

One way to effectively communicate this point is to depict the potential of a particular approach as a slice of the overall “energy pie.” Consider biofuels from this perspective. A Department of Energy report estimates that cellulosic biomass could provide a carbon-neutral source of ~30% of U.S. transportation fuel needs (7). Given that the transportation sector accounts for ~30% of U.S. fossil fuel consumption (8), the potential contribution of cellulosic biofuels to the current U.S. fossil-fuel carbon footprint is 30% of 30%—i.e., approximately 10% (Figure 1).

At first glance, the cellulosic biofuels’ slice of the overall energy pie might appear small. But given that addressing a problem of this magnitude will require a portfolio of approaches, a slice that comprises 10% of the pie is a major contribution. It is critical that we communicate both the promise of plant biology in contributing to renewable energy production along with a realistic assessment of the size of the slice of the pie that any particular approach can provide.

I want to end this final letter of my term by thanking the membership of ASPB for the honor of serving as president this past year. We have a great Society because it has so many involved members and a staff in Rockville that runs every aspect of our operation with an unsurpassed level of dedication and professionalism. As I move to the post of past president, our Society is fortunate to have Rob McClung as our president and Sally Assmann as our president-elect.

Rick Amasino
amasino@biochem.wisc.edu

REFERENCES
1. M. Granger Morgan, “Don't Grandfather Coal Plants,” Science 314 (November 17, 2006): 1049; http://www.sciencemag.org/cgi/content/short/314/5802/1049
2. http://www.conservationfund.org/gozero
3. Department of Energy, “Biofuels for Transportation” (July 2007 version); http://genomicsgtl.energy.gov/biofuels/transportation.shtml
4. Raymond E. Gullison, Peter C. Frumhoff, Josep G. Canadell, Christopher B. Field, Daniel C. Nepstad, Katharine Hayhoe, Roni Avissar, Lisa M. Curran, Pierre Friedlingstein, Chris D. Jones, and Carlos Nobre, “Tropical Forests and Climate Policy,” Science 316 (May 18, 2007): 985–986; http://www.sciencemag.org/cgi/reprint/316/5827/985.pdf
5. George Monbiot, “Selling Indulgences,” The Guardian (October 18, 2006); http://www.monbiot.com/archives/2006/10/19/selling-indulgences/
6. Richard Amasino, “Energy and Plant Biology (President’s Letter),” ASPB News 34 (January–February 2007): 1; http://www.aspb.org/newsletter/janfeb07/01pl34_1.cfm
7. Department of Energy, “Breaking the Biological Barriers to Cellulosic Ethanol: A Joint Research Agenda” (2006); http://genomicsgtl.energy.gov/biofuels/b2bworkshop.shtml
8. Bureau of Transportation Statistics, “Figure 14-1: U.S. Energy Consumption by Sector, 1994–2004” (2005); http://www.bts.gov/publications/transportation_statistics_annual_report/2005/html/chapter_02/figure_14_01.html