At the Darlington New Build (new nuclear power plant) hearings, Greenpeace and other environmental groups became involved in the public hearings and the environmental assessment process, not with the intention of improving the safety of the eventual plant, but with the intention of raising every trivial concern they could imagine (ie completing a full life cycle assessment of all greenhouse gases produced by the project) and using every trick (chaining themselves to a portable table during the hearings) they could think of to delay and increase the cost of the project. Eventually, they hope, if they can make the project too expensive or too uncertain of approval, backers will give up and look elsewhere. Among Greenpeace's other recommendations included one preventing any time restrictions on oral presentations at the public hearings. (Filibuster anyone?)
This is not to say that every single concern they raise is invalid. But its hard to take their concerns seriously when its well known that the only result they are interested in is one where the nuclear power plant isn't constructed.
(Although I have less knowledge of the situation facing the Pacific Gateway pipeline, I'm willing to bet that it is not dissimilar.)
As it pertains to Canada at Durban, I think Canada is the least of the environmental movements' concerns if what they are looking for is a real cap on carbon dioxide emissions. Asking the developed world to pony up $100 billion in indulgences (in addition to all the subsidies for green power and other domestic environmental projects) for the fast growing economies of China and Brazil while they run roughshod over the environment and while Europe's economy is imploding may be of greater importance than any obstructionism Canada can muster.
But that's just my opinion.