FORT MCMURRAY, Alta. - A brief helicopter tour of the oilsands Saturday wasn't enough to shake Archbishop Desmond Tutu's conviction that the industry is doing massive harm to both the climate and the environment.
"It is important that we do something about the horrendous effects and impacts on the only world we have," he said after the brief Suncor-sponsored flight that took him over part of the company's operations.
Earlier that day, Tutu's judgment of Alberta's oilsands had been harsh.
"The fact that this filth is being created now, when the link between carbon emissions and global warming is so obvious, reflects negligence and greed," Tutu told more than 200 rapt attendees at a conference on oilsands development and treaty rights in Fort McMurray.
"Oilsands development not only devastates our shared climate, it is also stripping away the rights of First Nations and affected communities to protect their children, land and water from being poisoned."
During the flight, Tutu listened to running commentary from Suncor executive Mark Little and seemed to acknowledge the company's efforts to mitigate its impacts and work with aboriginal groups.
"When a good thing is done, if you are honest you say this is something that is to be commended," he said.
But during the flight, Tutu told Little how many people had come to him during the conference to express their environmental concerns.
"Almost all the people who made observations spoke about the effect of the oil industry," he said.
Chief Allan Adam of the Athabasca Chipewyan First Nation, co-sponsor of the conference, responded cautiously to Tutu's uncompromising remarks.
"People have their own opinion," said Adam, whose band does about $270 million worth of business with oilsands companies a year. "It is filthy, it is gut-wrenching to see the mass displacement of land to get at the resource.
"(But) we're not anti-development. We want to do this right and there is an avenue to do this right."
The archbishop, who won the Nobel Peace Prize for his role in the fight against apartheid, has previously signed a petition against the Keystone XL pipeline project and called it "appalling" in a newspaper opinion column.
Tutu, 82, has also called for boycotts of events sponsored by the fossil fuel industry, for health warnings on oil company ads and for divestment of oil industry investments held by universities and municipalities, similar to measures that were brought against South Africa's old apartheid regime.
Industry supporters have pointed out that the oilsands' contribution to the amount of heat-trapping carbon dioxide produced globally is minuscule.
Davis Sheremata, a spokesman for TransCanada Corp., the company that wants to build Keystone, said in an email that fossil fuels have a positive impact.
"Oil powered the jet that flew Mr. Tutu to Canada from Africa, produced the fuel for the helicopter tour he had planned of the oil sands, and helped manufacture the microphones and TV cameras for his press conference," Sheremata wrote.
During the flight, Little tried to assure Tutu of Suncor's concern for local people.
"We really are focused on ensuring we are living up to the commitments and intent that are in the treaties," he said.
But Tutu didn't back down from his earlier remarks that humanity must act together to end a threat that is already affecting people around the globe.
"This is why I have stood in solidarity with communities across Canada and the United States that are opposing the proposed oilsands pipeline," he told the conference. "The struggle of citizens against the pipelines puts them on the front lines of the most important struggles in North America today."
Despite his rhetoric, Tutu urged people from all sides to work together. He pointed to the experience of his own country overcoming generations of racial intolerance as an example of how widely differing positions can be brought together through mutual goodwill.
"Magnanimity is not a river that flows in one direction only. It is a bridge built of reasonableness and the acceptance of others that enables human beings to navigate barriers that keep us apart."
In a conference room tangy with the slight smell of sweetgrass, Tutu said humanity must learn to think of itself as one family.
"You can't be human all by yourself. You need other human beings to be human."
Tutu's remarks, leavened by his trademark infectious laugh, ended with the crowd on its feet while he chanted, "we are connected."
Adam said Tutu's appearance will help his nation's cause.
"It puts pressure on government to realize we're getting world-renowned citizens coming together and speaking about the issue," he said. "That has to be addressed in a way where First Nations people have to sit at the table make sure their positions get (heard).
"However (Tutu) does it and whatever he does, it's a great feeling."
Little wasn't so sure.
"I don't think (Tutu's criticisms) are particularly helpful," he said. "We want to talk about real steps forward."
Olthius Kleer Townshend, a Toronto law firm specializing in aboriginal law, is the other sponsor of the conference. It wraps up Sunday.
Also on HuffPost