Sure, I could take a stab at it, and then maybe Tim could follow up.
I think it's critical, that two-thirds figure, and let's put it into context, that's if there's not wide scale use of things like carbon capture and storage technology, and that's certainly an option, and we stand behind it. We think it's potentially viable in places such as the oil sands, except the hard numbers of it is that it needs a price on carbon upwards of $90 a tonne for it to be economically viable without massive public subsidies.
Right now Shell's Quest CCS project requires over $850 million in taxpayer subsidies in order for them to go forward with it. It will be a case study and a pilot for the rest of the industry, but it's incredibly expensive, and given the price signals and the regulatory signals to the industry right now, it doesn't make economic sense to expand beyond that. That's why you have companies such as TransAlta dropping these projects at their electricity plants, because it just doesn't make economic sense.
If you shift the subsidies away from fossil fuel production and towards cleaner fuel production, you'll start to see the playing field tilt so that those sectors can start to compete. You can also see, through market mechanisms such as cap and trade or a carbon tax, that you can start to see the line of sight on the business case for even more reductions from the oil sands.