We participate in a bigger community, so the model we developed in Canada is one of roughly 30 or so around the world. There are about 30 centres like ours in other countries that develop and use the kinds of models that we have. One thing we do is compare one to another and ask how well our model compares to other models. How well does our model compare to observations? We're constantly evaluating the model as we try to improve it.
In terms of the big challenges, the things we're really trying to work on now are some aspects of the feedback that Matt alluded to earlier, in the sense that as the climate changes, there are certain parts of the natural system that change along with it in ways that can enhance emissions from natural sources. These include changes in the ocean and the way the ocean takes up carbon.
Right now, the ocean takes a lot of the carbon dioxide that we put into the atmosphere; it gets into the deep ocean through circulation. As the ocean warms up, that circulation changes and the ability of the ocean to take up carbon can change, so we're doing a lot of work on that.
We're also looking at the extent to which, as the climate warms, the carbon that is currently locked in frozen form—in permafrost, for example—can be released as that permafrost thaws, and enter the atmosphere.
The role of wildfires is another area in which we're working. We're building all these capabilities into our model so that as we go forward, we can try to simulate these feedbacks and make more quantitative estimates of how they affect the climate.