In 1988, the World Meteorological Organization teamed up with the United Nations Environment Programme to form a body with an even more cumbersome title, the Intergovernmental Panel on Climate Change, or, as it quickly became known, the I.P.C.C. The I.P.C.C.’s structure was every bit as ungainly as its name. Any report that the group issued had to be approved not just by the researchers who collaborated on it but also by the governments of the member countries, which today number a hundred and ninety-five. The process seemed guaranteed to produce gridlock, and, by many accounts, that was the point of it. (One of the architects of the I.P.C.C. was the Reagan Administration.) Indeed, when the scientists drew up their first report, in 1990, the diplomats tried so hard to water down their conclusions that the whole enterprise nearly collapsed. Every five or six years since then, the group has updated its findings, using the same procedure.

It’s in this context that the latest I.P.C.C. effort, released last week, has to be read—or, more likely, not read. Even the shortest and snappiest version of the report, the so-called Summary for Policymakers, which, at forty-one pages, is just one per cent of the length of the full document, is, in its mix of the technical and the turgid, pretty much impenetrable. Still, it manages to terrify. Owing to humans, the report states, the world has warmed by more than one degree Celsius—nearly two degrees Fahrenheit. Global temperatures are now higher than at any other time in the past hundred and twenty-five thousand years. Anthropogenic warming, the report observes, is already producing fiercer heat waves, heavier rainstorms, and more violent cyclones. In the coming decades, still hotter heat waves and worse flooding are to be expected, as events that are now considered extreme become commonplace. On Twitter, the climate activist Greta Thunberg described the I.P.C.C. report as a “solid (but cautious) summary of the current best available science.” The U.N. Secretary-General, António Guterres, called it a “code red for humanity.”

Of course, these days, you don’t need to be a climate scientist to know which way the smoke is blowing. As Corinne Le Quéré, a climate modeller at the University of East Anglia and one of the authors of the I.P.C.C. report, told the Washington Post, “It’s now become actually quite obvious to people what is happening, because we see it with our own eyes.” Just before the report came out, the Dixie Fire, burning northeast of Sacramento, became the largest single fire on record in California. (Last summer’s August Complex Fire is still the largest over all, but it was made up of multiple fires that started separately.) On Wednesday, the National Weather Service warned, “Stifling summer heat to stretch from coast-to-coast.” That day, about two hundred million Americans were under some kind of heat advisory.

Elsewhere in the world last week, the situation was similarly grim. The city of Siracusa, in Sicily, set what appears to be a new European temperature record of 119.8 degrees. More than sixty people were killed by wildfires in Algeria, which was also experiencing intense heat. Wildfires in Greece prompted the country’s Prime Minister to declare a “natural disaster of unprecedented dimensions,” and in the Chinese province of Sichuan more than eighty thousand people were evacuated because of flooding caused by torrential rains.

As the world fried and boiled, Washington continued to do what it does best, which is argue. On Tuesday, the Senate approved its much touted bipartisan infrastructure package. It allocates billions of dollars for climate-related projects, such as upgrading the electrical grid and improving public transportation. But the level of funding falls far short of what is needed, and key provisions—including standards that would compel utilities to move away from fossil fuels—are missing. Meanwhile, the bill contains a great deal of spending that’s likely to increase carbon emissions. Senate Democrats have promised to do better in their $3.5-trillion budget-reconciliation bill, the broad outlines of which they approved last week, on a party-line vote. The reconciliation bill is supposed to include, among many other climate-related measures, incentives for utilities to switch to cleaner energy sources, and penalties for those that fail to. But, in an awkward twist, drafting the details of this program will fall to the Senate’s Energy and Natural Resources Committee, which is headed by the fossil-fuel-friendly Joe Manchin, Democrat of West Virginia. In the House, progressive representatives have pressed Speaker Nancy Pelosi not to schedule a vote on the infrastructure package until the final budget-reconciliation bill has been approved by the Senate. Moderates have countered by threatening that they won’t vote for the resolution that would begin the budget process in the House until there is a vote on the infrastructure package.

Every delay matters. Three decades have passed since the I.P.C.C. released its first report. During that time, annual global emissions have nearly doubled, and the amount of carbon in the atmosphere put there by humans has more than doubled. As a result, the world is rapidly approaching thresholds that no sane person would want to cross. The goal of the Paris Agreement, approved in 2015, was to hold “the increase in the global average temperature to well below” two degrees Celsius and to try to limit the increase to 1.5 degrees.

The I.P.C.C. considered five possible futures. Under one scenario—the most optimistic, though by no means the most realistic—carbon emissions will fall to zero during the next few decades, and new technologies will be invented to suck tens of billions of tons of CO₂ from the air. Even in this case, average global temperatures are expected to increase by 1.6 degrees Celsius by the middle of the century. Under a more likely scenario, the world will warm by two degrees Celsius by then, and almost three degrees by the end of the century, and in a not-at-all-implausible scenario temperatures will rise by 3.6 degrees Celsius—or 6.5 degrees Fahrenheit—by around 2090.

What will summer be like as temperatures continue to rise? In the carefully vetted formulation of the I.P.C.C., “many changes in the climate system become larger in direct relation to increasing global warming.” In other words, we really don’t want to find out. But, unfortunately, we are going to.