Assuming that you want to deal with the person's misinformation or skepticism and not leave the room (which you are, after all, entitled to do), there are various ways in which an argument around climate change myths can be negotiated. Australian psychologists and "debunking" experts John Cook and Stephan Lewandowsky propose a fact-based conversation that doesn't engage too much with the myths of the other side.

The reasoning behind this idea, says D.r Christopher Dwyer at Psychology Today, is that it takes the power away from the myth itself; centering the facts in the conversation means they become more important than the myth. Facts should also, Cook and Lewandowsky also note that your facts should be carefully chosen to refute all the supporting pillars of the myth.

The Greater Good Institute at Berkeley points out that debates aren't often effective if the people involved are extremely defensive or aggressive. The opposite approach may seem to be the best option. "The less you try to force a particular set of views on someone, the freer they’ll feel to reflect honestly on what they think — and maybe even revise their thinking down the line."

People happen to enjoy defending themselves against aggressive attacks when they're absolutely sure they're right, according to research by Dr. Jack Gorman and his daughter Dr. Sara Gorman. The New Yorker reported in 2017 that their research found "people experience genuine pleasure — a rush of dopamine — when processing information that supports their beliefs. “It feels good to ‘stick to our guns’ even if we are wrong,” they observe." So having a full-on fight is likely only going to make a climate change denier dig their heels in.

Psychologist Jonas Kaplan told Vox in 2016 that people can feel personally threatened by arguments about their beliefs, and that perceived insult — even if it's subconscious — makes them less likely to change their minds. The better way to target this, he says, is to make explicit to yourself the fact that this person (their selfhood, personality and history) and their beliefs about climate change are separate things, even if that's incredibly hard. That separation will make it easier for them to put down their defensive guard and listen to what you're actually saying.

People who resist facts in arguments, according to a long-held belief in psychology, are experiencing the "backfire effect," which is supposed to make people confronted with facts that contradict their beliefs even more adamant about them. According to this theory, showing facts to a climate change denier will just make them deny it more intensely. However, the backfire effect appears to be a myth itself.

The Washington Post reported in 2017 that in a series of studies involving over 10,000 people, no backfire effect was seen, and that long-term, people did indeed "heed factual information," pay attention to facts, and perhaps change their minds. Facts might not be a magic pill — we always filter what we hear and feel strongly emotionally attached to various beliefs — but it's good to know that a factual argument won't push people hard in the opposite direction.

Interestingly, a study in 2018 revealed that sometimes laws can actually change our minds. When scientists measured public attitudes about a ban on plastic bottles before and after it was introduced in San Francisco, people were less opposed as quickly as 24 hours after the law was introduced. The short time frame indicated that nothing else had shifted; it was literally just a matter of public policy change and our adjustment to it. The BBC reported at the time that "we rationalize the things we feel stuck with," meaning that, if governments adopt policies that acknowledge and respond to climate change, people will follow suit, since they just have to live with it.

It can be frustrating to have a conversation with someone you love who disagrees with you, but it's helpful to lean on facts and know when you need to gracefully exit.