Thousands of climate activists, including University of Toronto students, skipped their lectures to rally at Queen’s Park during the Global Climate Strike on September 27, demanding government action against the climate crisis.

But what happened to the U of T students who went to their lectures and classes?

Dr. Dan Weaver, an assistant professor at the Department of Physical & Environmental Sciences at UTSC, recalled teaching a first-year class that day in a Twitter thread in December.

For the students who attended, he turned his lecture into a question-and-answer period to address climate crisis denial.

Climate crisis denial refers to being doubtful of the overwhelming scientific consensus and implications of the climate crisis. A recent survey by The Angus Reid Institute found that 10 per cent of Canadians believe that the climate crisis is simply a theory, and 20 per cent think that the crisis is a natural occurrence, devoid of human contributions.

Events preceding Weaver’s lecture

Weaver and colleagues signed an open letter to U of T to have class officially cancelled on September 27 in order to allow for students to attend the climate strike. Despite this request being denied, professors were instructed to not penalize students of their absence.

Weaver took this opportunity to initiate a class discussion on climate crisis denial, since he inferred that in this sample of  students, there would be climate crisis deniers present.

Speaking with The Varsity, Weaver recalled: “It was a very quiet class to begin with, very unsure whether they can ask, what they can ask, [and] what would my reaction be.” Weaver did not criticize any students for their views, but rather welcomed their questions and answered their inquiries with research-based evidence.

He continued by explaining that, as an instructor in an educational role, “What I can contribute from the classroom is an opportunity to engage with the science of the issue, and in particular with an audience that hasn’t had the opportunity most likely to talk to someone in the field directly.”

Engaging students and encouraging them to ask questions

Weaver evaluated the impact of his efforts by the frequency and type of questions he received over the course of the semester. “Because when someone continues to come back and ask follow-up questions, they are now intellectually engaged.”

From his viewpoint, “I already won: they are thinking critically.”

“Some people who are very passionate about this or other issues are much too quick to put down people of the ‘wrong opinion,’” noted Weaver, “and tell them to believe [and] get on board. That is the wrong approach.”

“There is a lot to be gained by giving people the opportunity to just ask questions in an honest and sincere way, and I think that is critical and often missing.”

Breaking down three common questions asked by climate crisis deniers

One of the main reasons for climate crisis denial is that some deniers don’t trust the consensus “that [the] climate is changing, and we are the cause, because of [information from] computer models,” Weaver explained.

Climate modelling utilizes mathematical computer programming to predict, to its best ability, natural and human impacts on the progression of climate change based on atmospheric, land, ocean, and sea level measurements.

Weaver continued, “We have teams… across at least a dozen countries doing it independently and coming to the same results… reproducing past climates and making predictions about where things are going.”

Another common reason promoting climate crisis denial is that “the narrative that climate change is entirely controlled by the output of the sun.” This view is promoted by the Canadian non-governmental organization Friends of Science Society — which Weaver said is one of “the world leaders in climate skepticism.”

Weaver countered their belief that, as he described it “The sun is a primary driver of [the changing] climate.” Weaver explained, “[The sun] is not the only one that controls it; it is a lot more complicated than that — that narrative sells a very simple answer to a very complicated question.”

Weaver continued, “If we had no atmosphere, the sun would still warm the planet, but the overall average temperature of the planet would be below freezing… The atmosphere is very important for moderating climate.”

In an email to The Varsity, the Friends of Science Society falsely disputed Weaver’s characterization of the organization. “Friends of Science Society sees the sun as the main direct and indirect driver of climate change, not carbon dioxide from human industry,” it wrote. “Friends of Science does acknowledge that humans contribute nominally to climate change, and CO2 emissions have a nominal role in that.”

The society’s position that humans have a small impact on the climate crisis contradicts the conclusions of the United Nations Intergovernmental Panel on Climate Change. According to the panel’s Fifth Assessment Report, it is “categorical in its conclusion: climate change is real and human activities are the main cause.”

A related common question from climate crisis deniers is, “Are we really having an impact, or is it all natural variability?” Addressing this, Weaver noted that “the climate naturally has variability and trends associated with it,” and these trends have been tracked, such as the measurements of the output of the sun during its 11-year solar cycle.

Weaver explained, “If you have an 11-year cycle and you think that climate is being driven entirely by the sun… logically then you expect to see this 11-year cycle in the climate going up and down, tracking with the sun.”

“And [then] we look at the data — is that actually what is happening in the climate? No, it’s not — there has to be more going on.”

Resources for understanding research on the changing climate

Weaver suggested the National Aeronautics and Space Administration’s Global Climate Change website as a resource to learn about the physical implications of the climate crisis. It provides information about the current state of the planet, including current measurements of carbon dioxide, global temperature, ice sheet melting, and sea levels.

Additionally, Weaver recommend looking at  the Climate Lab Book, a blog maintained by climate scientists featuring data visualizations of weather and climate patterns.

For discussions regarding climate crisis denial led by credible climate scientists, consider the blog RealClimate. If you prefer alternatives to blog platforms, Dr. Katherine Hayhoe, an atmospheric scientist, engages with the public on Twitter and YouTube to discuss climate crisis denial.

“The best resource if you are a U of T student is probably to go talk to a faculty member involved,” noted Weaver. “You have that privilege that most people don’t have.”