This story originally appeared in The Guardian and is part of “Climate Crimes,” a special series by The Guardian and Covering Climate Now focused on investigating how the fossil fuel industry contributed to the climate crisis and lied to the American public. Mark Hertsgaard is Covering Climate Now’s executive director.

Today is a day of history-making climate drama in Washington. At the Capitol Hill end of Pennsylvania Avenue, an unprecedented event: The CEOs of four of the world’s biggest private oil companies are summoned to testify under oath to Congress about their companies’ decades of lying about the lethal dangers their products pose.

There’s no mystery about who the villains are in this drama, only about how Big Oil will play this pivotal moment in the climate emergency: Will these executives finally admit their companies’ lies and take responsibility for the havoc they’ve caused? Or will they keep lying, if only by proclaiming that they are now climate champions working to solve the crisis engulfing humanity?

Oil company executives have dodged previous requests to testify before Congress on these issues, and one can easily understand why. The case against them, drawn from their own files, is detailed, plentiful, and damning.

As voluminous investigative reporting dating back to 2015 has documented, ExxonMobil, Shell, BP, and Chevron have known since the 1980s at the latest that burning oil, gas, and coal would overheat the planet and imperil civilization; their own scientists told them so. They did it anyway.

The companies not only hid their knowledge about what was coming; they spent millions of dollars telling the public that global warming wasn’t real. Indeed, 31 percent of Americans still don’t accept that climate change is happening, according to a new poll commissioned by The Guardian, Vice News, and Covering Climate Now. Which helps explain why the Republican Party can stand in lockstep opposition to President Joe Biden’s climate agenda and pay no apparent political price.

Big Oil’s history of deception and obstruction has yielded hundreds of billions of dollars in profits, salaries, and stock options for the executives scheduled to testify today. But it has also put humanity on track to a “catastrophic” future of scorching heat, ruinous drought and storms, and relentless sea level rise—just as Big Oil’s scientists projected decades ago.

Today, the witness docket at the House Committee on Oversight and Reform includes the Big Oil 4: Darren Woods of ExxonMobil, Michael Wirth of Chevron, David Lawler of BP, and Gretchen Watkins of Shell Oil. Scheduled to join them are the CEOs of two oil industry trade associations: Mike Sommers of the American Petroleum Institute and Suzanne Clark of the US Chamber of Commerce.

These executives will have the chance to earn their multimillion-dollar paychecks at today’s hearing. Facing questions from such ace interrogators as Representatives Katie Porter of California and Alexandria Ocasio-Cortez of New York, they will somehow have to explain why their companies kept their knowledge of fossil fuels’ deadly effects secret for so long.

The CEOs would seem to have two options. They can fess up to their companies’ sordid history and pledge to make amends. Or they can deflect, stonewall, and continue lying, with the extra twist that now they’d be lying about the decades of lies they’ve already told.

But lying under oath is perilous, especially when those lies are refuted by your own documents. The stakes double when your companies face dozens of lawsuits citing those lies and seeking billions of dollars in damages. The attorneys general offices in Massachusetts, Minnesota, New York, and other jurisdictions presumably will be watching today’s hearing closely, keen to seize upon any false statements they can introduce as evidence in their own cases.

Still, lying is what these companies know. ExxonMobil, for example, has insisted that it never deceived anyone, citing studies its experts published in scientific journals—a defense that conveniently ignores the company’s abundant public messaging that cast doubt on climate science. Similar lying persists today with oil companies’ gauzy ads celebrating all the wonderful technologies they’re developing to be part of the solution to climate change, a theme the CEOs surely will stress in their opening statements.

Meanwhile, some of the victims of Big Oil’s lies are offering their own eloquent testimony at the other end of Pennsylvania Avenue. Outside the White House, five young climate activists, ages 18 to 26, have entered the ninth day of a hunger strike in a desperate plea that their government avert the hellish future awaiting them.

These young people are afraid, and angry, and they have every right to be. The companies that put them in this position owe them, and all of us, a profound apology, as well as restitution for the horrific damage they have done.