and, no, the ndp didn't have a better idea.
what the ndp ran on was increasing taxes on oil exports, and redistributing it towards social systems like health care and child care. their policy was not only completely disinterested in reducing emissions, but explicitly focused on making the government even more reliant on the industry. this was coming out of the ndp winning government in alberta, and getting into bed with the oil industry.
if your primary concern was the environment, as mine was, the ndp was actually probably the worst choice in that election. while the conservatives just flat out don't care one way or the other, at least they weren't running on structurally tying the country's finances to oil revenue, like they do in venezuela. that would have been an utter disaster. the liberals were at least running on embracing environmentalism as a capitalist profit making venture, and while that's certainly not the ideal option, it's a step in the right direction. but, they haven't done it. at all.
in the end, we can only know what what actually happened. so, we know that the liberals broke all of their promises around meaningful environmental legislation and systemic change - that's empirical, we can measure it. we don't know what would have happened if the ndp would have won. would they have built all these refineries, like they were promising? how would they have reacted to the collapse in oil prices? we can't know.
but, despite being disappointed with the liberals, i still think the ndp were the less green option in that election. and, i'll argue the point every day for the next three months if you'd like, because i still think the ndp are the worse option for green voters.