I noticed that many questions that are tagged ecological-footprint are in fact questions about the ecological or environmental impact of a product. I think the problem is that the terms 'impact' and 'footprint' are rather similar. However, the concept of ecological footprint is different from environmental impact.
Ecological footprint is a specific measure; it's the area of Earth needed to sustain a particular lifestyle. Environmental impact is more broad and includes all impacts, positive and negative, of a product, policy or service on the environment.
Since we didn't have an environmental-impact tag yet, I've created it. I also improved the excerpt of the ecological footprint tag to make the difference more clear. I already retagged a few questions, but in order not to flood the homepage with retagged questions, I will continue doing so with only a few questions each day over the next week.