Canada will aim to reduce its greenhouse gas emissions that cause global warming by 45-65 percent by 2050, ... The bill introduced Thursday in the House of Commons would also apply intensity-based targets until 2020, allowing emissions to continue to rise until then.There're actually a lot of advantages of this target over something like Kyoto. First, it sets a definite long-term target, which Kyoto does not. This provides a more stable environment for people and companies to make investments in emissions reducing technology. Second, it allows emissions to grow in the near term, i.e., does not require sharp near-term cuts in emissions, as Kyoto does. Most economists agree that allowing some near-term growth followed by steeper cuts later provides the lowest cost trajectory to get to your preferred emissions level.
The downside of a longer term target is that it can be used as a stalling tactic if the administration really doesn't want to do anything about the problem. However, one need not wait long to find out if that's the case. While some emissions growth can be tolerated near-term, deviations from business-as-usual need to occur within a few years to hit the target in 2050 at minimum cost. Thus, if Canada is serious about this, we need to see some near-term actions relatively soon.
Finally, the target is not quite ambitious enough. In order to stabilize the climate at around 550 ppmv (i.e., double pre-industrial CO2), we need to reduce world emissions to about 2 GtC/yr, about 80% less than we're emittiong today. Their target, 45-65% reductions, would not be sufficient to do this if applied to the entire world.