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Message from the Director: Moving beyond the single "green" metric

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Contributed by David Constable, Director, ACS Green Chemistry Institute®

Over the past year the quantity and diversity of articles published in The Nexus is one demonstration of just how much is happening in green chemistry and engineering. This is evidenced by the significant amount of content contributed from different people in the community—from educators to industry and government scientists to students—as well as by the number of articles on each months topic our staff works hard to illuminate.  In reality, it’s impossible to fit everything that is happening in green chemistry and engineering into a monthly newsletter. This month’s issue is no exception. That said, we are excited to see a momentum that continues to build and bodes well for our collective future.

This October issue is focused on metrics, tools, and assessments—a topic that is of great personal interest and in my opinion, sadly neglected by many.

It isn’t that people don’t incorporate any metrics in their thinking, it’s that they only incorporate one or perhaps two metrics and equate a positive attribute for that one or two metrics as evidence that a chemical or a new reaction chemistry, or a catalyst is “green,” “greener”  or more sustainable. For example, a product that is derived from biomass is lauded as “green” or “environmentally friendly” because it is agriculturally based. Or a catalyst is seen as necessarily being green because it is able to do an asymmetric chiral coupling. But is that really the case, and is a single attribute sufficient for calling something “green” or “greener?”

I’d like to think that we are not so easily seduced to think along these lines, but the number of journal articles I routinely see, or the presentations I see at most green chemistry conferences and symposia suggests otherwise. So, what would I like to see?  First, embrace the complexity that attends calling something “green” or “sustainable.” It takes more than a single metric. Second, recognize that when you take a multivariate/multi-metrics driven approach, the answer about something being “green” is likely to become a bit gray; i.e., it’s not a black and white decision. What you invariably will encounter is that you trade impacts of one kind or another. The emphasis should be on arriving at the optimum solution amongst all the trade-offs.

Let me return to the example of a chemical derived from biomass. In the plus column would be things like it may be derived from waste biomass, it is not derived from petroleum (it is renewable, hopefully), and perhaps it is obtained in high concentration.  On the negative side there are potential impacts associated with agriculture (land, water, fertilizer – nitrogen and phosphorus, pesticides and herbicides, transportation of the biomass, upstream and downstream processing impacts - water, waste, etc)  In other words, where you draw the boundaries of your analysis really matters, and it isn’t a simple picture. By taking these kinds of things into account, just as you should for a chemical derived from any source, be it from petroleum or otherwise, you are more likely to arrive at a chemical or product that is “greener” or more sustainable.

And that’s the third thing about metrics; they should always be done in comparison to something. It is unfortunate that many are looking for absolute numbers when we live in a relative world. We really need to move forward with decisions based in credible comparative data and we have some more work to do to make this happen.

Finally I’d just like to report on my recent trip to Georgia Tech in Atlanta, GA and the inauguration of their Renewable BioProducts Institute. Georgia Tech, as many of you probably know, is one of the top schools in the U.S. in science and engineering and it is unashamedly preparing students for work in industry. The Renewable BioProducts Institute is a new name for an Institute that has long been doing work with the forest and paper products industry. There is, however, a renewed emphasis on going past only fiber and continuing to develop a variety of chemicals from biomass. It was a great pleasure and honor to be a part of their day and a half symposium and hear the panel discussions of industrial and academic speakers. It is always great to see the clear needs of industry articulated and how the scientific and engineering capabilities of academic researchers can be used to solve real-world problems.The very best science and engineering are keys to successful innovation and I therefore have great confidence the Institute will continue to be very successful at delivering greener and more sustainable solutions.

As always, let me know what you think.


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