We all know the kinds of mistakes people make when they think the good times are never going to end.

We’ve seen it with celebrities who spend like there’s no tomorrow, and then sheepishly file for bankruptcy when tomorrow arrives.

But what about the mistakes you make when you think there is no future? Mickey Mantle likely shortened his Hall of Fame career because he never saw a bar he couldn’t close or a curfew he couldn’t ignore.

Approaching his 50th birthday and long out of baseball, he observed: “If I knew I was going to live this long, I would have taken better care of myself.”

It was a joke – and not an original one – but it reflected how Mantle viewed the world. His father and other male relatives had all died before they turned 40, and Mickey figured that was probably where he was headed, too.

As we come to the end of 2021 – a year I’m starting to think of as 2020, Part 2 – I can’t remember feeling so gloomy about the future.

We are probably going to see 1 million U.S. coronavirus deaths before the second anniversary of the pandemic. Democracy is under threat as states rewrite their laws to cement minority rule. And the Supreme Court is doing what everybody except Susan Collins knew it would do to reproductive rights.

But nothing is more frustrating than our ability to confront climate change.

We have known for at least 40 years that greenhouse-gas emissions are warming the planet. The science becomes increasingly convincing, and the natural disasters get more intense.

The United States has done more than any other country to bring us to this point, so we bear more of the responsibility than most other countries to fix it, even though the worst consequences are currently taking place elsewhere.

But politically we can’t take the steps that are needed. The Republican Party is organized around anti-elitist ideas that make a comfortable home for climate deniers. And the Democrats have a complicated coalition that includes both climate activists and conservatives who don’t want to do anything more than they have to.

And it’s not just the politicians. The price of health care and education can go through the roof, but the smallest increase in gas prices is political poison, which makes elected officials timid.

This is disappointing to me, but it’s traumatic for young people, who report being massively pessimistic about their future.

A poll by two researchers at the University of Bath in the United Kingdom found that climate anxiety is widespread and strikes deep.

“Over 50 percent felt sad, anxious, angry, powerless, helpless, and guilty,” the researchers found in the study published in the British journal The Lancet. “Over 45 percent said their feelings about climate change negatively affected their daily life and functioning, and many reported a high number of negative thoughts about climate change. Respondents rated the governmental response to climate change negatively and reported greater feelings of betrayal than of reassurance. Correlations indicated that climate anxiety and distress were significantly related to perceived inadequate government response and associated feelings of betrayal.”

Can you blame them? When they wonder whether they could ever bring children of their own into such a broken world, all we can offer is an explanation of the filibuster rule.

Conservatives like to scold about the federal budget deficit and how it will limit the lives of their grandchildren, but this is the real legacy that my generation is leaving behind.

The climate deniers are part of the problem, but there are probably more climate “moderates” who say that they “believe” in climate change but they don’t want to do anything about it. Sometimes they’ll admit that the problem seems too big and expensive to deal with, and we will need to adapt to underwater coastal communities and abandoned desert cities while continuing to drive around in SUVs.

This is the kind of mistake you make when you think that there is no hope. Some degree of optimism is necessary for our survival. Change doesn’t have to be bad.

In my grandparents’ life span, we went from horses and buggies to landing on the moon. We ought to be able to find a way to live with electric vehicles and wind mills.

I’m not going to try to explain to a teenager who Mickey Mantle was, but I would try to explain that the most important thing that they could do is imagine a better future and live as if it’s on its way. Don’t make the mistakes that come with thinking that there’s no tomorrow.