As the other panellists have noted, many factors can affect greenhouse gas emissions. The key in isolating the impacts of any one factor is to use statistics to try to determine what is attributable to the carbon pricing and what is not. In other words, what would the carbon price have been absent that carbon tax in B.C.?
The statistical analysis that Nick and others have done says that emissions would have been even higher if B.C. had not implemented its carbon tax. That is through rigorous, very credible econometric analysis.