That's a tough question to answer. On the one hand, if the carbon tax were eliminated and not replaced by any measures, Canada's greenhouse gas emissions would probably increase a little more than the current track Canada is on. In addition, it would be perceived as disregard for the agreements Canada has signed on reducing greenhouse gas emissions.
On the other hand, if we scrap the carbon tax and don't replace it with any measures, and Canada increases its emissions by a little or a lot, I don't think it would have a significant impact on climate change, given Canada's ranking in terms of greenhouse gas emissions.
That's why I say it's difficult to answer that question in the context of a hypothetical scenario where the carbon tax is eliminated and not replaced with anything. Canada could be a free rider, do nothing and still benefit from other countries' efforts to reduce greenhouse gases. However, that would cause all kinds of issues in terms of diplomatic and international relations.