“It was not our language and not how we approach things,” West-Heiss said. “We are disappointed that they felt like they had to approach the situation like this. We much prefer to have interaction and conversations to move sustainability and climate action forward as an office and as a city.”

While West-Heiss said the city "certainly understand(s)" the Sunrise Movement's concern with Suncor’s sponsorship of the event, she said Denver also believes the company's position as a stakeholder is still valuable.

“We certainly understand them and respect their perspective, but as the city we really feel like it’s important to bring every stakeholder to the table and we think we can be more effective and take a larger piece of the action forward through that," West-Heiss said.

Andrea Czobor, a journalist from Denver, attended the summit and was handed a copy of Sunrise's letter. At first, she was impressed that “this particular event somehow or somewhat renounced Suncor because of their practices.”

“I fell for it,” Czobor said. “And being a journalist and having a background in understanding this type of document and understanding communication methods and how people spread misinformation so easily, I’m kind of shocked.”

Czobor said she was disappointed to see that “people around here are actively spreading things that shouldn’t be.”

Part of the reason Czobor believed the letter was because one summit keynote speaker on the agenda, Thomas Tonatiuh Lopez Jr. with the Indigenous Youth Council, called out Suncor.

“Because of the Suncor refinery, the ZIP code and the place where I call home is now one of the most polluted ZIP codes in the U.S.,” Lopez said, referring to ZIP code 80216 of Denver neighborhoods Globeville and Elyria-Swansea. “Make no mistake Suncor, I am not here to be your friend. I am not here to sit at a mediation table and meet you halfway. That time has long past. I’m here to tell you that we do not want you in our communities anymore.”

After sharing a press release that explains the letter was a fake, the Sunrise Movement stood by its disinformation tactics. Michele Weindling, a coordinator with Sunrise Colorado, said the group wanted to mirror the tactics of The Yes Men. On their website it says the group fights “neoliberal policies through humor and trickery.” They once impersonated a Dow Chemical spokesman on the BBC.

In another event, members of the climate activist group Extinction Rebellion attended a House Climate Crisis Committee meeting in Boulder. There they falsely announced that Gov. Jared Polis had declared a climate emergency, and CBS Denver later reported the false declaration as true.

Weindling said part of Sunrise's plan was to make the media believe the letter was real for “as long as possible.”

“Which is a risk, and that was something that we grappled with, because our relationships with the media are really important to us,” Weindling said. “But modeling the leadership of what past actions have looked like, it's been really important that they look as authentic as possible.”

When asked if Sunrise felt this tactic was the right idea, for a movement that bases itself in the sanctity of facts and truth around climate change, Wiendling argued for its purpose.

“It puts our representatives in an uncomfortable position where they can't just divert attention away from the activists. They have to address what we've called them out for, and then they either have to agree and declare a climate emergency or they have to publicly backtrack that they're unwilling to do so,” Wiendling said. "That’s more important than temporary disinformation."

Max Boykoff, an associate professor at the University of Colorado Boulder and the director of the Center for Science and Technology Policy Research, studies science and environmental communications and recently published his book "Creative Climate Communications."

Tactics like Sunrise's can have different impacts on different audiences, Boykoff said, and some will find Sunrise's actions, "clever and creative, so therefore they will see it as effective."

But not everyone will feel that way, and he said the research shows it.

"In order to find common ground on these issues, in order to bridge difficult conversations, violating trust isn't an effective way to go over the medium and long term," Boykoff said. "Public citizens who are then burned by something like this and feel as though their trust has been violated, not to mention the elected officials who have been impersonated or the media who have been targeted. This then has a chilling effect on how to trust the messages coming from that group in the future."

Boykoff said he won't tell people how to communicate when it comes to climate change, because "there really is no silver bullet communication strategy." But an attempt to deceive a wide audience through the media "may have violated some fundamental considerations of authenticity and trust that that will do some damage going forward," he said.

Sunrise's actions could have a larger influence on the impacts of climate communication, he said.

"In this time of fake news and post-truth, there's certain tactics within context that seem to make much more sense than others," Boykoff said. "And so this one at this time seems to be pretty damaging for wider efforts that are looking to build bridges."