Well, because we have not accepted the approach that's been taken to the definition of these sinks. We believe the reason Canada pushed, as it did, back in the day when this was discussed for that exemption, was primarily to allow Canada a somewhat easier time to address the ultimate objectives.
What we laid out here, which we would acknowledge is a very significant set of reductions over the next period of time, to 2050, was something concrete and specific that we felt there could be reasonable scientific certainty about.
I think you would probably agree with me that the calculation of the land-use change emissions and sinks is still very much an emerging science. It's difficult to have confidence in the kind of giga-tonne numbers that are flowing from those kinds of definitions at this point in the science.