I would say that, in many cases, the carbon tax is the most cost-effective way of doing that. Does that necessarily mean it's necessary? Well, no. We could find other ways of accomplishing that, but those ways, in some instances, will be more expensive.
I would say, with agriculture—because again, I'm here to talk about agriculture—that carbon pricing only takes you so far. In this sector, I would not limit greenhouse gas policy simply to carbon tax for a variety of reasons.
First of all, you're looking at a lot of non-point source emissions. The emissions aren't always easy to measure. Second, as we've seen in a few other sectors, for the most part, this tends to be a low-margin sector that is highly susceptible to international competition, so then you have to start worrying about carbon leakage. Third, there is a real role for innovation to play, as you state. There is a role here for government to do things like pilot projects, to look at projects that help farmers purchase this new technology and so on.
So while I do think that the carbon tax is useful in many instances, I do not believe, and we do not believe, that the carbon tax is necessarily a one-size-fits-all solution and that, to meet our Paris commitment for greenhouse gas, we are going to need a wide array of policy instruments.