According to the latest evidence, Earth is hotter now than it has been in any of our lifetimes but Canadians are less concerned about climate change than they were a decade ago.

NASA says the last three years have each been the three hottest on record, and 16 of the 17 warmest years have occurred this century, according to the World Meteorological Organization. This winter, we've witnessed Arctic sea ice dwindle to record lows.

Yet, climate concern reached its "pinnacle" in Canada — outpacing all other worries, including the economy — around 2007 and has since waned, said Frank Graves, president of EKOS Research.

Economic anxieties came back to the fore in the wake of the "Great Recession" and continue to dominate, but that's not to say climate worries have disappeared. They still rank near the top of the list for most Canadians, although views on the topic vary widely.

People in Alberta and Saskatchewan, Graves said, are two to three times more likely than those in the rest of Canada to be skeptical of man-made climate change. But an even bigger division can be found — nationwide — along political lines.

More than half of Conservative supporters have consistently said they "don't believe all this talk about greenhouse gas emissions causing climate change" in EKOS polling. Outside the Conservative base, only about one in 10 Canadians say the same thing.

"(Conservatives) are literally five times as likely to be on what we maybe call politely the enviro-skeptic — or, maybe less politely, the climate-change denier — side of the equation," Graves said.

Data from a 2014 EKOS poll on climate change beliefs, by political affiliation. The research company says internal polling data from 2017 yielded nearly identical results. (EKOS)

So why have Canadians become relatively less worried about climate change as the indicators of a warming planet have become more and more extreme? And why do beliefs split so strongly along partisan lines?

Well, for one, it's not just climate change.

Similar divides exist on a range of issues, both in Canada and around the world. The phenomenon has been studied by psychologists, sociologists and political scientists and the growing body of literature suggests humans are simply wired to see the same things differently.

And, once we see something a particular way, it's hard to change our minds.

'Myside' bias

Many people are familiar with the term "confirmation bias," a phrase used to describe human beings' tendency to seek out evidence that confirms their existing beliefs.

Researchers also talk about "myside bias" to describe how people tend to evaluate claims that challenge their beliefs more stringently, while giving those that are consistent with their views the benefit of the doubt.

"We don't want to be overly challenged in terms of our belief systems and what we're doing, because it causes us to have an identity crisis," said Lianne Lefsrud, a professor at the University of Alberta who has studied climate change beliefs in the province's scientific community, specifically.

Back in 2007, she designed a detailed and open-ended survey that was completed by more than 1,000 members of the Association of Professional Engineers and Geoscientists of Alberta (APEGA).

More than 99 per cent of respondents agreed the climate was changing, but they disagreed on why — and Lefsrud found they fell roughly into three camps.

About a third of respondents believed humans' greenhouse gas emissions were the main cause, while another third was convinced the changing climate was primarily a natural phenomenon. The final third wasn't sure, but suggested it was likely some combination of man and nature, with neither being an overwhelming factor.

Are our carbon emissions the primary cause of climate change? Only 36.3 per cent of Alberta engineers and geoscientists surveyed in 2007 were convinced of that, according to a U of A study. (Mark Ralson/AFP/Getty Images)

Those working within government were most likely to believe in man-made climate change, at 45.2 per cent, while those working at the top level of the oil and gas industry were least likely, at 16.2 per cent.

Lefsrud said this was not a matter of simple denial; the views expressed in the survey were nuanced, informed and scientifically literate. Many respondents "had questions with regards to the degree of certainty associated with the modelling" in climate science, she said.

Indeed, the 2007 report from the Intergovernmental Panel on Climate Change (IPCC), which presented the strongest evidence to date of human-caused climate change, still used the phrase "very likely" — meaning more than 90 per cent certain — to qualify that assertion.

The language was upgraded to "extremely likely" in the 2014 IPCC report, meaning more than 95 per cent certainty.

Lefrsud said the views of engineers and geoscientists have likely changed since 2007 as well.​

But outside of scientific circles, how much does new evidence actually change people's beliefs?

Not as much as you might think.

The 'backfire effect'

The desire to cling to one's beliefs can be so strong that being presented with evidence to the contrary can actually make people more convinced of something that's wrong, according to research from political scientists Brendan Nyhan and Jason Reifler.

A decade ago, they documented what they call the "backfire effect" in a study that tested popular — but false — beliefs among both conservatives and liberals in the United States.

The study found conservatives were more likely to believe Saddam Hussein had an active weapons of mass destruction program just prior to the 2003 invasion of Iraq, while liberals were more likely to believe then-U.S. president George W. Bush had banned stem-cell research.

Did Saddam Hussein have an arsenal of WMDs? Did George W. Bush ban stem cell research? The answer is no in both cases, but researchers found strident liberals and conservatives reluctant to change their beliefs, despite available evidence. (Nikola Solic/Associated Press and Anne-Christine Poujoulat/AFP/Getty)

What's more, the study found it "did not reduce overall misperceptions" when subjects were presented with information to counter their false beliefs.

In fact, it sometimes did the opposite.

Misconceptions actually grew among conservative subjects who were presented with information about how the U.S. ultimately found no active arsenal of chemical or biological weapons in Iraq.

"In other words, the correction backfired — conservatives who received a correction telling them that Iraq did not have WMD were more likely to believe that Iraq had WMD than those in the control condition," the researchers wrote.

On the stem-cell research "ban," by contrast, the correction was found to have a convincing effect "among centrists and individuals to the right of center, but fails to significantly reduce misperceptions among those to the left of center."

What drives what?

Coming back to Canadians' beliefs about climate change and the current debate around carbon pricing, all this raises a sort of chicken-and-egg question.

Do people's beliefs about climate change inform their views on carbon pricing?

Or do their views on carbon pricing drive their beliefs about climate change?

Brendan Frank isn't sure which comes first, but says the two issues are nearly impossible to separate in ordinary conversation.

As an Ottawa-based research analyst with Canada's Ecofiscal Commission — an independent, non-partisan research group devoted to pollution pricing in general — he admits he lives in bit of an "echo chamber" when it comes to both topics.

But while home in Calgary to visit family for the holidays, Frank went out of his way to speak with with dozens of Albertans about the province's new carbon tax. What he heard was in line with what most Albertans told CBC News last December as part of an in-depth look at the policy.

They don't like it.

To see how the carbon tax would affect Alberta families, CBC visited six different households that offer a cross-section of the population in mid-December, 2016. Most were opposed to the policy. (Robson Fletcher/CBC)

Frank said he had previously underestimated how deep-rooted the opposition in Alberta was and found it valuable to step out of his professional bubble.

He also had some advice for trying to bridge the divide when speaking to people with an opposing point of view.

"Listening is really, really important," he said.

"You should go into a conversation with the assumption that you have something to learn. Even though someone may disagree with you, try giving them the benefit of the doubt."

As a pollster, Graves said it will be fascinating to keep following climate change beliefs over the coming months, in the wake of the election of U.S. president Donald Trump.

Canadians have typically expressed more concern over the environment than Americans, he said, while the number of Conservatives who say they're skeptical of climate change has remained "pretty rock stable over the past few years."

But he wonders if both of those things might start to shift.

"We do see in Canada that this populist movement has had on the Conservative base; it looks a little more like the Trump base than it did in the past," Graves said.

"It seems it's more permissible to just say, look, I think climate change is a lot of hooey in an environment where you have Donald Trump winning the presidency."