Scales of Green

Union of Concerned Scientists Automaker Rankings (2007)

Nov 26

Posted: under Green Companies.


In recent weeks, the Big Three automakers — GM, Ford, and Chrysler — have been under fire for asking for a bailout from Congress after spending years ignoring consumer interest in more fuel-efficient, environmentally-friendly cars.  Nearly a year ago, the Union of Concerned Scientists (UCS) released its fourth assessment of the top automobile manufacturers’ environmental performance, and for the fourth time since 1999 the three American companies had the three worst scores given.  But what about the UCS report itself?  How does it come out in terms of its transparency, governance, and coverage of environmental issues?

Transparency: Glass*

The 49 page report includes an extensive Appendix detailing the methods used to calculate its scores. While the data and calculations themselves are not provided, clear source references and explanations are.  It includes a discussion of both what is and is not covered by the scores, although the implications of the specific scoring method used are not discussed.

Governance: Oligarchy (with Monarchic, Republican, and Aristocratic Elements)

While the report is attributed to a single individual, Don MacKenzie, the acknowledgements state that UCS is solely reponsible for its contents.  Given that Mr. MacKenzie is a vehicles engineer and not a senior staff member at UCS, it is likely a group of people reviewed, edited, and approved the document.  Nevertheless, Mr. MacKenzie clearly played a key role in its publication, and furthermore, the report’s results are based on data gathered from government websites, which in turn include data gathered from the companies themselves.  Thus, while the report’s design was ostensibly controlled by a non-profit oligarchy, it was also indirectly affected by decisions made by other types of governance as well.

Coverage: Hedgehog

While more extensive in its coverage than’s data, the UCS rankings are still limited in their assessment of environmental performance.  Their global warming scores only take into account carbon dioxide emissions due to fuel use, transportation, and production, and ignore other greenhouse gases such as methane, nitrous oxide, and HFC-134a and the climate impacts of automobile production.  The smog scores are limited in the fact that they are indeed smog scores, and only include smog-forming NOx and non-methane organic gases, while ignoring other pollutants such as ozone, particulate matter, and carbon monoxide.  Nevertheless, as individual measures of specific impacts, these scores are relatively robust.  And the fleet-wide assessments do provide a broader perspective on each company’s overall environmental performance than any other assessment currently in existence.

This Scale’s “Greenness:”

The UCS Report claims that its “analyses provide objective measures of each manufacturer’s true environmental performance,” but some important points should be remembered:

1. These rankings are based on proxy measures of each fleet’s climate and smog impacts, and have a high degree of uncertainty to them.

2.  The scores weight climate and smog equally – if we consider climate to be significantly more urgent than smog, for example, Volkswagen might be more highly ranked than Hyundai (or, if we weighted smog higher than climate, Nissan might do better than Hyundai).

3. The ratings are based on 2005 data (the most recent available), and each company’s performance may have shifted significantly since then.

4. The rating method looks at the average performance of each company’s models, rather than at the number of models above or below a certain performance threshold (e.g. GM frequently claims it has more models that get 30 MPG or more).  As a measure of overall performance, UCS’s model appears to be the correct choice, while the latter approach would be a better measure of “greener choices” provided to consumers.

5. Despite these caveats, UCS does provide the most comprehensive assessment of these automaker’s environmental performance, and its limitations reflect a general lack of data rather than an institutional emphasis.

* For an explanation of the Transparency, Governance, and Coverage “ratings” above, please click here.

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