LCA and Environmental Intelligence? aper or plastic? Incandescent or compact fluorescent? Returnable or recyclable? Local food or (mass-produced) organic food grown miles away from your mouth? Which is best environmentally? These are tough questions that researchers are trying to answer through life-cycle assessments (LCAs). LCAs represent a growing portion of research articles in ES&Tsabout 8% of research articles in February and March of 2009. And the articles are garnering increased media attention and scientific citations. Witness one of our most popular recent articles that was chosen as the ES&T Policy Paper of the Year on “food-miles” by Christopher Weber and H. Scott Matthews at Carnegie Mellon University (2008, 42 [10], 3508-3513). Sometimes the answers are a bit counterintuitive, like it’s better to eat chicken from afar than red meat grown locally. Graedel and Allenby define LCA as “an objective process to evaluate the environmental burdens associated with a product, process or activity ... and to evaluate and implement opportunities to effect environmental improvements” (Industrial Ecology, 2nd ed., Prentice Hall: New York, 2003 [my emphasis]). But is LCA really “objective”? Recently I asked my Sustainable Systems class to evaluate paper towels versus electric blow-dryers as a means of drying hands in public restrooms. Forty percent of the students came to the conclusion that paper towels were superior from an LCA standpoint, and 60% thought it was better to use electric hand dryers. Is LCA really objective when such opposing conclusions can be reached? Looking more closely, students had weighted (valued) media (e.g., air vs solid waste vs water pollution) or issues (dioxin from the kraft paper process vs greenhouse gases from coal-fired electricity) differently. Likewise, I received conflicting assessments when students were asked to compare incandescent bulbs versus compact fluorescent lights (CFLs) versus lightemitting diodes (LEDs). Some of them automatically rejected CFLs because they contained 1-5 µg of mercury, and no local destination was available for recycling the bulbs. Never mind that the vast difference in energy used by incandescent bulbs came from coalfired power plants, which emit far more mercury than CFLs do. (That’s an example of one group simply missing an important environmental impact in its LCA.) But clearly it’s difficult to compare various products with slightly different purposes and impacts across various media and time and spatial scales. Do we value global more than local, air more than soil, and animals more than algae? Do effects in other countries matter less
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10.1021/es900867c
2009 American Chemical Society
Published on Web 04/10/2009
than effects in our own country? Do humans matter more than fish or fungi? The beauty of LCA is not necessarily in its objectivity. Certainly, LCA cannot make the choice for us. Rather it lays out all the assumptions and quantifies the estimates in the common denomination of dollars (currency), greenhouse gases, energy, materials, and/or environmental impact for all to examine. It opens our environmental books in a transparent fashion, and that’s its real strength. Time magazine, in a recent special issue on the “10 Ideas Changing the World Right Now”, cited trend number 10 as “Ecological Intelligence”. It’s the notion that everyone wants to know (quantitatively) the most ecologically intelligent thing to do, mode of travel, product to buy, lifestyle to live, and food to eat. Time is advocating for LCAs. We’ve come a long way in only 10 years. I remember my first Ph.D. student who used LCA as the backbone of his dissertation on burning switchgrass instead of coal at coal-fired power plants. Poor soulshe had a terrible time convincing the faculty committee that such a simple “accounting procedure” was even worthy of a Ph.D. in environmental science. As I ponder all these interminable questions, I have melancholy for the “good old days” when we really knew an environmental insult when we saw one. Maybe that represents progress? I note recent anniversaries of 20 years since the Exxon Valdez oil spill in Prince William Sound in Alaska (March 24, 1989), the 30th anniversary of the Three Mile Island radiation leak in Pennsylvania (March 28, 1979), and the 23rd anniversary of the Chernobyl nuclear disaster (April 26, 1986). Let’s hope we don’t need a LCA to know which way the wind is blowing. Whatever the real benefit of LCA, it’s here to stay and is changing our way(s) of life. The question is no longer “paper or plastic”, but where is your reusable tote bag? It’s not “incandescent or CFL”, but how much mercury is in that CFL bulb, and is it recyclable? We welcome the increase in LCA papers in ES&T as a modern accounting tool allowing us to consider our decisions more carefully and to tread a bit more lightly on the earth.
Jerald L. Schnoor Editor
[email protected] May 1, 2009 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 2997
