Robertson is the only Canadian among 60 global mayors gathered in Rome to promote Pope Francis' environmental encyclical, which denounced the fossil fuel-based world economy that exploits the poor and destroys the Earth.
Robertson said in a telephone interview from Rome on Tuesday that he met with delegates, listened to a talk from the Pope and signed a declaration that states "human-induced climate change is a scientific reality and its effective control is a moral imperative for humanity."
The mayor will speak to delegates Wednesday about the economic success Vancouver has seen by greening the city and tackling climate pollution.
"It's a huge honour to be invited into the Vatican, into the Pope's presence and have the most important political issues of our time addressed by such a key faith leader," said Robertson. "I think it's helped reinvigorate the spirit for a lot of us."
Shane Buckingham, media secretary for federal Environment Minister Leona Aglukkaq, responded to Robertson's comments in an email, saying the current government is the first in Canadian history to achieve a net-reduction in greenhouse gas emissions.
"We have set a fair and ambitious target for Canada that is in line with other major industrialized countries to achieve further emissions reductions leading up to 2030," he said.
Buckingham said the government's sector-by-sector approach includes responsible regulatory measures, such as phasing out traditional coal-fired electricity across Canada and making cars and light trucks more fuel efficient.
The Vatican conference comes just months before the scheduled Oct. 19 federal vote and year-end United Nations Climate Change Conference in Paris.
Robertson said he and other Canadian mayors have committed to pushing the federal government to endorse bold targets for carbon reductions at the Paris conference, and they'll keep their pressure up as Canadians prepared to head to the polls.
He said Vancouver is also among a group of cities focused on eliminating fossil fuels and shifting towards 100-per-cent renewable energy.
"I've heard other mayors and governors wondering where Canada's leadership is on climate change," he said. "We're in the bad books globally. With the Paris negotiations looming, you know, we are not in a useful leadership role globally, so Vancouver's story is quite the opposite."
The Pope has become a hero to the environmental movement and has used his moral authority and enormous popularity to focus world attention on climate change and its effects on the poor.
Francis' other main priority has been to raise awareness about human trafficking. The Vatican conference is aimed at showing how both are related: The exploitation of the Earth and its most vulnerable people, with global warming often responsible for creating "environmental refugees" forced to flee homes because of drought or other climate-induced natural disasters.
"He's a very thoughtful human being," said Robertson of the Pope. "He's genuinely committed to tackling the world's toughest challenges from climate change to global poverty, which are taking a devastating toll.
"He's connecting the dots between these extraordinary struggles and taking leadership where most of us don't expect it."
(With files from Associated Press)
-- by Keven Drews in Vancouver
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