A pathway is a policy tool that helps you think through the choices, economic and others, that need to be made to achieve a set goal. It's generally accepted that there are likely to be different trajectories that countries will follow to achieve deep emission reductions, and those will be informed by their own circumstances. In Canada, people often talk about our cold weather, but our growing population could well be an even more significant factor. Our population has grown by 18% since 1990, and achieving our 2020 goals implies achieving a 26% reduction below 1990 levels in per capita terms.
So there is a range of considerations that will affect policy pathways. The key idea, though, is that all countries are taking action, and that they are working together to achieve a global outcome consistent with what the science tells us.