With Democrats holding the first debates of their presidential candidates tonight and Thursday in Miami — a city held hostage to the growing threat of climate disruption — consider this: Not a single question was asked about global warming during the 2016 general election debates.

Not one.

The midterm elections last year saw some mild improvement in the curiosity of journalists interrogating the candidates, but still fell woefully short. Just 29 percent of the debates held in competitive, statewide races in 2018 featured a climate warming question, even though 2017 and 2018 were some of the worst years on record for weather, according to an analysis by Media Matters.

Now, Democrats are embroiled in an internal spat between citizen activists, with the backing of some 2020 candidates and the Democratic National Committee over whether to hold one debate focused solely on climate disruption.

Yet public opinion surveys show a majority of Americans ahead of the press as a torrent of demoralizing disasters and doomsday climate studies pour forth daily. Voters increasingly recognize that the threats of catastrophe from global warming are no longer years or decades in the future, but here, now. Recognition by the public that human behavior is accelerating the heating of the Earth is up double digits over the past five years. Americans are asking: How do we resist despair? Where can we find leadership? And how should we live?

It's hard to ignore climate change when the consequences show up on our doorstep. Juiced-up hurricanes strafe Florida, Texas and Puerto Rico, the wildfire season in the West never ends, and farmers struggle to adjust to changing planting seasons and extreme flooding while battling pests that no longer die because winter doesn't get cold enough. In Miami, sea level rise means residents are dealing with "sunny day flooding" nearly three weeks of the year.

More than 30 years after the noted NASA climatologist James Hansen warned Congress that the world faces a climate emergency, the horrific disasters multiply — record heat, drought, deluge. Yet denialists hold sway. Their deception, aimed at discrediting the science of global warming, is backed by the money, propaganda, and lobbying of powerful individuals and corporations that reap huge profits from convincing the public to relax, there's nothing to worry about.

For years now, journalists by and large have asked politicians, "Do you believe climate change is real?" and left it there.

Sometimes we have asked them if they believe human activity causes climate warming.

Or whether they believe in science at all.

Asking such questions of candidates is worse than ignoring it altogether, for they suggest that denial is an acceptable interpretation of the facts. It isn't.

For voters to be able to vet the politicians on whether they have what it takes to lead us in confronting the emergency, we must know more than whether candidates acknowledge well-established science. We must ask those who would lead the nation at a time of peril what they will ask of us: How do we move beyond our reliance on fossil fuels to renewable energy sources? How do we rebuild the energy grid with efficiency and resilience as goals? How do we recover more swiftly from extreme disasters? How do we modernize our infrastructure to reduce emissions? How do we adjust our life styles to provide a secure future for coming generations?

Politicians don't like to get pinned down on commitments that will require hard choices once they get into office. This debate season, it's more important than ever to get them on the record now, while voters still have the opportunity to judge them for their willingness to lead.

That old curmudgeon George Bernard Shaw once said that journalists "are unable, seemingly, to distinguish between a bicycle accident and the collapse of civilization." That's no longer sufficient. We must not repeat our indifference of past debates and allow the candidates to treat global warming as a trivial pursuit. We can do better, starting tonight in Miami.

Bill Moyers, a journalist for almost 50 years, is president of the Schumann Media Center.