I think it's fair to say that when environmentalism blossomed in the 1970s, it was partly due to the fact that people were already cutting back on car journeys and petrol because of the oil shortage. When companies and governments are looking at alternatives to gas-guzzlers purely for economic reasons, it's easier for the green voice to be heard, and then other issues beyond emissions-related ones (e.g. wildlife) could be put out by the same pathway.
So how would our attitudes to the environment be different in a TL where, for whatever reason (no Yom Kippur war?) there isn't a 1973 oil crisis? Everyone can keep buying cars with high fuel consumption (one knock-on effect is that the Americans don't get into their pickup truck craze) and alternative oil sources (e.g. the North Sea) are probably not exploited to the same extent as OTL.