To start his US tour, the Pope stated that "climate change is a problem which can no longer be left to a future generation. When it comes to the care of our 'common home,' we are living at a critical moment of history." Speaking on behalf the poorest people – those who will be most adversely affected by climate change, but have done the least to cause the problem – the Pope's message is a powerful moral call to action.Can this call overcome cultural and political barriers to change? In the near term, the push for a new climate treaty in Paris represents a key decision point for the planet. The Pope's encyclical, released in June, surveys the science on climate change, then comments:"It is remarkable how weak international political responses have been. The failure of global summits on the environment make it plain that our politics are subject to technology and finance. There are too many special interests, and economic interests easily end up trumping the common good and manipulating information so that their own plans will not be affected."[para 54]These words may sound familiar to observers of Canadian politics when it comes to climate change. Election 2015 has so far offered up a soft form of climate denial, with the three main political parties at best talking in vague terms about reducing greenhouse gas emissions, while endorsing plans that would dig Canada ever deeper into fossil fuel production and export.The encyclical saw it coming: "Consequently the most one can expect is superficial rhetoric, sporadic acts of philanthropy and perfunctory expressions of concern for the environment, whereas any genuine attempt by groups within society to introduce change is viewed as a nuisance based on romantic illusions or an obstacle to be circumvented." [para 54]In its challenge to the status quo, the Pope has more in common with the Leap Manifesto's vision of "a country powered entirely by truly just renewable energy, woven together by accessible public transit, in which the jobs and opportunities of this transition are designed to systematically eliminate racial and gender inequality."As foreshadowed by the encyclical, the Leap Manifesto's call for leadership and action was largely dismissed by mainstream elites, who apparently see no problem with the truly radical proposal of pumping ever more of Canada's abundant fossil fuel reserves into the atmosphere.The good news is that this path is becoming increasingly difficult to tread. The collapse of commodity prices, which has exposed Canada as a high-cost producer, is a shot over our bow. In a carbon-constrained world, most of Canada's reserves will need to remain underground, undeveloped.On the ground, new pipelines and other fossil fuel infrastructure are meeting opposition wherever they are proposed. Enbridge's Northern Gateway Pipeline, approved by the Harper government in spite of massive protest, may never get built in the face of opposition by local communities and First Nations. For Canada-US relations, a central issue of tension has been the delay, and possible rejection, of the Keystone XL pipeline.Parallel to protests and blockades, a new movement has sprung up demanding institutional divestment from fossil fuel energy (and corporations) and re-investment in clean technologies. A new report totals up divestment commitments from 430 institutions and 2,040 individuals across 43 countries at $2.6 trillion in assets.The cost of renewable energy has come down substantially and is increasingly competitive with fossil fuels. It is widely recognized that we have a political problem not an economic or technological one, and that the costs of acting are less than the costs of doing nothing.Even leaders of the Group of 7, earlier this year, agreed to phase out fossil fuels by 2100. Canada was "successful" in defending its perceived interests by deferring the date from 2050, the target proposed by Germany. If made into a national priority, rich countries like Canada could get there in a generation.The only question is how much damage we do in the interim. Every year we delay we transfer well-being from many people in the future to a small number in the present. More refugees, for example, will spill across borders due to climate change, in the aftermath of droughts and extreme weather and rising sea levels.The Pope demands that we in wealthy nations not become numbed to the plight of the poor as we try and address our environmental and climate problems. The encyclical comments that "a true ecological approach always becomes a social approach; it must integrate questions of justice in debates on the environment, so as to hear both the cry of the earth and the cry of the poor."To get to this promised land, we must let go of our fear that action will be painful. That means our actions must be steeped in concepts of climate justice: providing decent and plentiful jobs building the green infrastructure we need, ensuring that no one is left behind, and that the high emitters causing the problem are first to act.As Canadians vote in a few weeks time, we should reflect on how we move forward together with compassion and justice on the overarching challenge of our times.Marc Lee is a Senior Economist in the BC Office of the Canadian Centre for Policy Alternatives, and Co-Director of the Climate Justice Project, a multi-year research project funded by the Social Sciences and Humanities Research Council of Canada.