Psychologically speaking, humans have been collectively acting as if they have been addicted to fossil fuels, but refusing to recognize the extent of their dependence, let alone engaging in any serious rehabilitation.

Confronting this reality is about to occur in earnest, as part of the 2020 U.S. presidential election campaign. Expect to see important questions being raised about global warming during candidate debates. Do not expect 2020 to be like 2016 when global warming issues received virtually no attention in debates between Donald Trump and Hillary Clinton.

The country is polarized about climate change policy, just as it is polarized about other political issues, such as border security and abortion. The Center for Climate Change Communication, based at universities Yale and George Mason, provides reliable survey data on how climate change issues are currently viewed by the American electorate.

For Democrats, global warming ranks as the third most important issue, and for moderate to conservative Democrats it ranks as eighth most important issue. In contrast, for Republicans, global warming ranks between 23 and 29 in terms of importance. Well over half–64 percent–of Democrats indicate that global warming will be an important determinant of who they vote for in 2020, while for Republicans the corresponding figure is 12 percent.                

You may recall that U.S. Rep. Alexandria Ocasio-Cortez, D-New York, and Sen. Ed Markey, D-Mass., in February introduced their version of a “Green New Deal,” a grand plan that would eliminate all U.S. carbon emissions, while creating new, good-paying jobs in clean energy industries.

As I wrote in a previous column in April, political discourse about a Green New Deal is just beginning, and a carbon tax is likely to be part of it.

With a carbon tax, which I support–along with 3,300 other economists in the U.S. who recently signed the Economists’ Statement on Carbon Dividends–people and business would have to pay a fee for their carbon emissions.

Yet even as I wrote about the importance of instituting sensible carbon tax policies, the behavioral economist in me realized that there was strong psychological resistance by the public to imposing these taxes.

Most people, afterall, code taxes as losses. But a recent New York Times story illustrates how powerful “framing” the issue can mitigate negative reaction, and nudge people to reconsider: In ballot measures held in Michigan and Nevada, the story reported, climate change mitigation policies passed when initiatives were framed to emphasize the benefits of improved health and job creation.

Framing is a behavioral term made famous by psychologists Amos Tversky and Daniel Kahneman, and refers to how outcomes are described.

The two psychologists’ work emphasizes that people frame outcomes as gains or losses relative to reference points, and that people can respond differently to situations depending on how outcomes are framed. This is important because as a general matter, people are more sensitive to losses than they are to gains of the same magnitude.           

The U.S. presidential candidate to date who has proposed the most concrete plan for addressing global warming is Jay Inslee, the Democratic governor of Washington. Notably, Inslee has placed climate change at the top of his agenda, and the issue will define his campaign.

A tweet from Ocasio-Cortez described Inslee’s climate plan as “the most serious + comprehensive” among plans advanced by all declared candidates. Though he is only polling between zero and one percent nationally, Inslee has garnered enough donor support among Democrats to qualify for the first Democratic debate later this month.

My reading of Gov. Inslee’s climate change plan suggests that a lot of thought has gone into putting together a set of proposals that balances environmental goals and psychological determinants that drive political feasibility.

Again, while many of us believe carbon taxes are necessary, he knows they don’t resonate positively with voters. So Inslee’s plan emphasizes standards over carbon taxes. And Inslee’s standards apply only to “new” automobiles and buildings, not assets currently in place, a feature which reduces perceived losses.

In the 2020 election, the open question is whether the threat of global warming will resonate psychologically with enough voters, and whether those voters will feel a sense of urgency that is commensurate with the magnitude of the threat.

We can see and feel for ourselves that the climate is changing. In the last two years, Americans have experienced severe floods in the Midwest, disastrous wildfires in the West, unusually destructive hurricanes in the Southeast, major drought in the Southwest, and punishing cold winters in the North.

Most Democrats accept the message from mainstream climate scientists who for decades have been telling us that global warming is the result of humans’ over-consumption of fossil fuels. In contrast, many fewer Republicans accept this message.

Part of the difference between Democrats and Republicans is driven by attitudes about regulation. Democrats by nature trust regulation to address social problems, while Republicans do not. Trust is psychological in nature.

In my view, although the position held by most mainstream climate scientists is essentially correct, significant psychological barriers are largely responsible for preventing many people from accepting the scientists’ message.

For this reason, psychology will invariably play a critical role in political discourse about climate change.

A version of this article originally appeared on May 27, 2019, in Forbes.