In a paper published in 2004 results from an inventive experimental study on negative eco-labels were presented.
It was noted that eco-labels in use today signify environmentally benign outcomes: "Choose this product, it is better for the environment than the average product."
A radically different strategy would however be to indicate negative outcomes with the purpose of trying to persuade consumers to avoid a product: "Do not choose this product, it is worse for the environment than the average product."
In an experiment it was shown that those with an intermediate interest in environmental issues (i.e. most consumers) were significantly more affected by a negative label, in comparison with a positive label.
This result is in line with those in the "Bad is stronger than god" review paper I mentioned in my previous post. To avoid a bad outcome really seems to be a much stronger tendency than to strive for a better, or more positive, outcome.
References
Baumeister, R. F., Bratslavsky, E., Finkenauer, C., & Vohs, K. D. (2001). Bad is stronger than good. Review of general psychology, 5(4), 323.
Grankvist, G., Dahlstrand, U., & Biel, A. (2004). The impact of environmental labelling on consumer preference: Negative vs. positive labels. Journal of Consumer Policy, 27(2), 213-230.