Studying For Environmental Sustainability Exam: Uncertainties I Wonder About

The Harper Government asserts a notion of "environmental hijacking", suggesting that the environmental movement in Canada has been overly influenced by outside/foreign nations. But when it comes to environmental issues when do local issues become global and vise versa? What determines the scope of concern?
The global climate has been operating fairly stably since the dawn of civilization and agriculture roughly 10,00 years ago, and while global warming and cooling are a natural element of that operation, human action is superimposed over natural climate cycles. To what degree are these cycles truly effected by human activity? Should we be operating as a global community? Are all local environmental issues automatically a global concern?
Yesterday I was having a conversation with some friends over a few causal beers, and we got on the topic of local activism. We were originally talking about the upcoming COP18 meeting in Khatar and the general failure of these global environmental meetings. One friend wondered whether these meetings were useless to hold as nothing tends to be solved and the carbon emissions required to transport representative leaders from all over the world are extremely counterproductive to the cause. The counter argument was that to cancel these meetings altogether was to give-up and although typically unsuccessful at least the effort was being made. We then began to discuss local activism and how it is through small community change that large-scale change is eventually sparked. So while Canadian environmentalists may or may not have been encouraged by foreign nations, this was likely the result of a successful local movement somewhere else sparking consciousness in other communities.
Which leads me to wonder why we don't treat the entire globe as our local community? Its so difficult to generate change from COP meetings because everyone is too busy seeking their personal agendas, but if we start to think as individuals from foreign nations as neighbors, couldn't these boundaries in perception be bridged? I think it all comes down to compartmentalization and specialization of knowledge--we fail to consider the alternative view point because we are so obsessed with our own. Don't get me wrong, knowledge specialization  has resulted in great technological advancement, that is inarguable, however when we look at the world through these fragmented lenses we miss the bigger picture. It takes using universal knowledge to truly generate change... is this impossible? Are we too narrow-minded to achieve such a level of awareness? Perhaps I have too much faith in the human race. We are a species that prides itself on specializing-- learning more and more about less and less until we know everything about nothing, maybe we are doomed.... With Harper at the wheel Canadian's definitely are.