For a brief moment on Thursday night, the complicated, daunting and terrifyingly overdue task of averting climate catastrophe came into focus as the second contingent of Democratic presidential hopefuls took the debate stage. Sen. Kamala Harris (Calif.), vowing to enact a Green New Deal, evoked the smoldering embers of a wildfire-scorched California town that firefighters tried to protect even as their own homes burned. South Bend, Indiana, Mayor Pete Buttigieg proposed a carbon price and farming policies that trap carbon dioxide while breathing new life into rural America. Former Colorado Gov. John Hickenlooper, deriding the Green New Deal as socialism and defending oil and gas companies, promised to work with industry to cut emissions as quickly as possible. Former Vice President Joe Biden pledged to up the ante on former President Barack Obama’s signature policies and marshal the United States’ power to lead the world. Sen. Bernie Sanders (I-Vt.), in a challenge to the fossil fuel industry, stated gravely: “The old ways are no longer relevant.” But when moderators asked all 10 candidates to name a legislative priority, just two answered climate change. Then the debate moved on. It was, undoubtedly, an improvement over Wednesday night’s first debate, when candidates spent just over 9 minutes discussing an emergency that threatens, even in best-case projections, destruction on a scale incomprehensible to most people. Yet the candidates didn’t spar. They didn’t offer specifics. They didn’t even get the chance to respond to the same questions so that voters watching the televised performance could compare answers. The combined 15 minutes of the first primary parleys made it clear: Democrats need a full debate devoted exclusively to climate change. As it happens, Democrats ― both voters and a majority of the politicians vying for their ballots ― want a full debate devoted exclusively to climate change. Activists began calling on the Democratic National Committee to schedule a climate debate months ago, gathering as of Thursday night nearly 223,000 signatures on an online petition. Washington Gov. Jay Inslee, running for president on climate change alone, championed the cause and rallied 14 other contenders, including Biden and Sens. Kirsten Gillibrand (N.Y.) and Elizabeth Warren (Mass.), behind him. A poll taken this month found that 64% of Democratic-leaning voters support the idea. And yet the DNC, the Democrats’ main party organ, remains steadfast against a full debate devoted exclusively to climate change. Why?

Wilfredo Lee/ASSOCIATED PRESS Democratic presidential candidates had a lot to say Thursday night on the debate stage in Miami, but little of it was about climate change.

Earlier this month, DNC Chair Tom Perez, responding to intensifying pressure from Inslee’s campaign, argued in an awkwardly defensive Medium post that such an event would unfairly favor the governor’s candidacy. But the 14 other candidates backing Inslee up refutes that explanation. On Thursday evening, the DNC told me candidates are free to participate in whatever forums they want, opening the door to an unofficial discussion. But absent the party’s marketing resources and official seal, such an event would be unlikely to reach the millions of Americans who tuned in to watch these past two nights. It’s conceivable that top Democrats don’t grasp the magnitude of the crisis at hand. Last October, a United Nations report authored by the world’s top climate scientists projected that humanity needs to roughly halve its still-surging emissions over the next decade or face warming beyond 2.7 degrees Fahrenheit above pre-industrial levels. At that point, the extreme weather, sea-level rise and droughts ― to say nothing of the geopolitical conflicts such stresses trigger ― are expected to cost $54 trillion in damages and cut millions of lives short. The National Climate Assessment, a report authored by scientists at 13 federal agencies, confirmed the findings a month later. Federal researchers in Hawaii detected atmospheric concentrations of carbon dioxide at 415 parts per million last month ― the highest levels since humans evolved. It’s no longer theoretical. Historic wildfires, floods and storms killed thousands of Americans in just the past two years. A cyclone virtually wiped Mozambique’s fourth-largest city off the map overnight in March. Temperatures soared to an oven-hot 120 degrees Fahrenheit in India this month. This week, wildfire flames turned 42,000 acres of the Florida Everglades to ash just 30 miles northwest of where the Democrats stood on the debate stage. Perez said the DNC received “more than 50 requests to hold debates focused on” issues including immigration, racism and voting rights. Yet climate change is not another player on that stage. It’s the stage itself. A climate debate is a platform to examine each of those topics with the urgency they deserve. Droughts are parching once-fertile land in Central America, sowing unrest and driving desperate migrants north to the U.S. border with Mexico. At Wednesday night’s debate, former Housing and Urban Development Secretary Julián Castro and Sen. Cory Booker (N.J.) teased out “a Marshall Plan” for Honduras, Guatemala and El Salvador. The proposal was framed as part of the discussion of immigration policy. How would such a plan help lower emissions in other countries? What responsibility does the United States, the world’s second-biggest source of climate pollution, have to shelter those whose equatorial homes are inhospitably hot?

MARVIN RECINOS via Getty Images A boy sits on an abandoned boat on what is left of drought-parched Lake Atescatempa in Guatemala.