Moderator Chris Wallace of Fox News guides the discussion on Wednesday between Democratic presidential nominee Hillary Clinton and Republican nominee Donald Trump.

Editor’s Note: John D. Sutter is a columnist for CNN Opinion who focuses on climate change and social justice. Follow him on Snapchat, Facebook and email. The opinions expressed in this commentary are his.

CNN  — 

In 2016, likely the hottest year on record, there’s one question US presidential debate moderators had a moral obligation to ask Donald Trump and Hillary Clinton: How do you plan to address climate change and rid the economy of fossil fuels?

Yet they never did.

That’s just unbelievable.

We’re already seeing seas rising in Miami, wildfires worsening in the West and deaths related to swollen rainstorms in Louisiana. The effects in the future, if we don’t curb emissions, will be much worse, including drowned coastal cities, supercharged droughts in the Southwest, mass extinction in the natural world and the likely end of the coral reefs.

Trump and Clinton couldn’t be farther apart on this issue, with Trump calling global warming a “hoax” masterminded by the Chinese and Clinton (while not bold enough) saying she will work to curb emissions and build on the progress of December’s Paris Agreement.

Everyone knows what the science requires: Zero-net carbon emissions by 2100, at the latest. Neither candidate would get us there, but Clinton would keep walking in the right direction while Trump would run back toward the coal era with eyes closed and ears plugged.

This is the most critical issue of our time. Future generations will look back perplexed at why it escaped our focus.

I bet millennial voters already feel that way. As an old-ish millennial (I was born in 1982, so I meet Pew’s definition, but barely) I can say the debate moderators and their questions largely failed to address my biggest concerns and those of my peers. Climate change, LGBT rights, education, student debt – all of that got shortchanged for (repeat) discussions of the national debt, Medicare, Social Security, etc.

Debate moderators, of course, have the unenviable task to trying to represent the awesomely diverse patchwork of interests that is the United States. But climate, particularly, is far too pressing for any of us to ignore. More tactically, it’s baffling that the interests of millennials were sidelined when the moderators surely must know we represent the largest age group in the country. Media companies love to pander to our tastes and wallets. So why then would they largely exclude us from these critical conversations about the future of America?

Vox’s Brad Plumer identified a few reasons they avoid climate, specifically.

“It’s possible the debate moderators don’t understand what’s at stake. It’s possible they don’t care. Or it’s possible they’re afraid that any question on the topic might seem too partisan. After all, Clinton thinks the issue is pretty serious and has a bunch of proposals to address it, whereas Trump says it’s all a hoax invented by the Chinese. Under the circumstances, even a halfway intelligent question about climate policy would sound ‘biased.’”

Some of those theories also make sense when applied to LGBT rights. I was stunned when Elaine Quijano – who, at 42, is the youngest debate moderator in decades – failed to ask the vice presidential candidates about their stances on LGBT issues.

Mike Pence, Trump’s running mate, voted against legislation to prevent LGBT people from being fired because of who they are (that’s legal in most states); wanted to use government money for “gay conversion therapy”; and called anti-LGBT-hate-crime legislation “radical.” He deserved to be interrogated on those bigoted stances. Maybe moderators, as Plumer suggests, are worried about being labeled partisan for telling it like it is.

That’s a shame because we millennials tend see these issues on moral terms.

As one of my Facebook friends suggested, perhaps younger-focused issues didn’t come up in the debates because we are in an unprecedented election, with Trump facing allegations of sexual assault and waffling on whether he supports the democratic process. “This wasn’t a normal series of debates so let’s not pretend,” he wrote. “One existential crisis at a time.”

That’s a fair point, but there was ample time to address climate, LGBT rights and education. According to Grist, the candidates only spent 5 minutes and 27 seconds on climate and environmental issues – mostly because Hillary Clinton brought it up on a couple of occasions. Out of 270 minutes, that’s so little time it’s inexcusable.

The moderators – ages 69, 63, 57, 49 and 42 – largely failed to reflect key concerns of younger voters.

In doing so, they missed an opportunity to bring younger people, who are far less likely to vote than older generations, into this process. And they failed hold the presidential candidates accountable for their views on climate, LGBT rights and education – three key issues that will shape this country many generations into the future.