Let’s be clear: This was avoidable,” a furious Varshini Prakash, the executive director of the Sunrise Movement, said in response to the latest United Nations climate report. The Intergovernmental Panel on Climate Change’s Sixth Assessment Report, released on August 9, “is apocalyptic, catastrophic, and nothing we haven’t been screaming about from the rooftops for years,” Prakash continued. “If Biden really wants to be a world leader on climate, he’ll heed this call and pass the boldest reconciliation bill possible.”

The UN climate summit in November (COP 26) will be one of the most important diplomatic gatherings in history; world leaders will literally decide the future of life on earth. The Paris Agreement, signed at the last major summit in 2015, obliges the world’s governments to limit global warming to “well below” 2 degrees Celsius (3.6˚ Fahrenheit) and preferably to 1.5˚C (2.7˚F). The IPCC report, which UN Secretary General António Guterres labeled a “code red” warning that must “sound a death knell for fossil fuels,” makes it irrefutably clear that more than 1.5˚C risks absolute, perhaps irreversible, catastrophe for people and natural systems worldwide.

Although 1.5˚C will bring significantly worse impacts than observed today, they would be dramatically more severe at 2˚C and almost inconceivably more punishing if temperatures rise still higher. The extreme heat and drought that sparked the Dixie Fire this summer now occur five times as often as they have historically. If temperatures rise 2˚C, they will occur 14 times as often.

Thousands of scientists have separately declared a “climate emergency,” in part because humanity must now move incredibly fast to avert far worse conditions in the years ahead. Global temperatures have already risen by 1.1˚C, and trends point to a ruinous 3˚C later in this century. To stop at 1.5˚C, emissions of carbon dioxide and other heat-trapping gases must be cut in half by 2030 and reach “net zero” by 2050, according to IPCC scientists, who add that this will require transforming the global economy at a speed and scale “unprecedented” in human history.

The challenge is imposing—but by no means impossible. Almost all major obstacles to transitioning to a climate-friendly global economy are political.

The solutions therefore must be political as well. The UN summit absolutely must not fail; governments must reach an agreement that credibly puts the global economy on track to 1.5˚C by slashing emissions in half by 2030. “Credibly” is the key. The agreement must not be weakened by the kind of corporate-friendly loopholes that marred the infrastructure bill recently passed by the US Congress, which included, among other appalling examples, $8 billion for “blue hydrogen,” a term oil companies invented for hydrogen produced by—wait for it—burning more fossil gas!

The US carries a unique responsibility as the world’s largest cumulative emitter of greenhouse gases. (China overtook the US in recent years to become the largest annual emitter, but cumulative emissions are what determine global temperatures.) Biden has talked a good game, pledging to cut climate pollution to 50 percent of 2005 levels by 2030, but his accomplishments to date fall far short of what’s needed for him to credibly pressure other countries to do more. And other countries must do more. In particular, China, India, and Russia—all large emitters—have so far refused to endorse the 1.5˚C target, a recipe for catastrophe.

The Sunrise Movement is correct that passing a reconciliation bill with ambitious climate provisions is imperative. But while activists focus their ire, and reporters their coverage, on Biden and fossil-fuel-friendly Democrats such as West Virginia Senator Joe Manchin, the congressional Republicans who’ve long been the main reason for America’s climate inaction largely escape censure. Politics is about power, and nothing concentrates a politician’s mind more than the prospect of being voted out of office. In the weeks remaining until COP 26, people power could change politicians’ calculations. Now is the time for politicians of all parties to hear, loud and clear: Either you do what’s necessary to preserve life on this planet, or we the people will make sure that the next election is your last.