Whatever words and phrases the Intergovernmental Panel on Climate Change may have been parsing late into Sunday night, its new report, issued Monday, boils down to yet another dire scientific warning. Greenhouse gas emissions need to peak by 2025 to limit global warming close to 1.5 degrees Celsius (2.7 degrees Fahrenheit), as targeted by the Paris Agreement, the report says.

In a way, it’s a final warning, because at the IPCC’s pace, the world most likely will  have burned through its carbon budget by the time the panel releases its next climate mitigation report in about five or six years. 

Even with the climate clock so close to a deadline, it’s not surprising that the IPCC struggled to find consensus during the two-week approval session, said Paul Maidowski, an independent Berlin-based climate policy researcher and activist. The mitigation report may be the most challenging of the three climate assessments that are done every five to seven years under the United Nations Framework Convention on Climate Change, he said.

The first two reports of each IPCC assessment cycle, one on the physical basis of climate science, and another about impacts and adaptation, are mostly based on unyielding physics, like how much global temperature goes up for every added increment of CO2, and how fast and high sea level will rise based on that warming.

But the mitigation report, which outlines choices society can make to affect the trajectory of climate change, has to reconcile those scientific realities with economic and political assumptions that are not constrained by physics, Maidowski said. Other researchers have described the IPCC report as a mechanism to determine what is politically possible, he added. If those assumptions—for example about future availability of carbon dioxide removal technology—don’t materialize, “then you are left with illusions, essentially,” he said.

The IPCC has “blinded itself” to deeper questions of sustainability and is thus asking the wrong questions, like how to decouple economic growth from greenhouse gas emissions, he added. Instead, it should be more up front about acknowledging the physical limits of the planet, and start asking how to downscale current resource consumption to a sustainable level.

The report found that “without immediate and deep emissions reductions across all sectors, limiting global warming to 1.5°C is beyond reach.” 

On the hopeful side, the panel noted that renewable energy costs have dropped by as much as 85 percent in the past decade, and that new policies in many countries have accelerated deployment of wind and solar power. 

Deforestation rates are dropping in some regions, which leaves more trees to take up carbon dioxide from the atmosphere, showing that improved agriculture and forestry practices can deliver “large-scale” emissions reductions. However, “land cannot compensate for delayed emissions reductions in other sectors,” the panel warned.

An Unrealistic Leap of Faith

The contradictions between scientific reality and hopeful political assumptions identified by Maidowski are clear in the new report, which says, on the one hand, that greenhouse emissions need to peak in the next three years, while also finding that average annual greenhouse gas emissions from 2010 to 2019 were higher than in any previous decade. 

Believing that emissions can peak by 2025 on that trajectory requires an enormous and unrealistic leap of faith, and many climate scientists, including Peter Kalmus, a federal climate researcher who organizes climate protests as a private citizen, are not buying it. 

“This IPCC report is absolutely harrowing. Wake up everyone,” Kalmus wrote on Twitter. “Brief summary of the new IPCC report: We know what to do, we know how to do it, it requires taking toys away from the rich, and world leaders aren’t doing it,” he continued.

Kalmus supports Scientist Rebellion, researchers who say the climate crisis requires much more drastic action than world leaders have been willing to take so far. The group marked release of the report with scientist-led protests at universities worldwide. University protests are part of a growing wave of activism aimed at disrupting normalcy to try and generate more public awareness of the need for transformative change, according to the Climate Emergency Fund, a nonprofit that funds climate protests.

Kalmus also focused on how much more carbon dioxide can be emitted before missing the Paris Agreement target. He said there are only about 400 gigatons left in the carbon budget, and the new report shows that the world is on a path to produce more than twice as much, with projected emissions from energy production, industry, transportation, development and land use adding up to about 850 gigatons of carbon by 2100.

“If just the currently planned stuff is built and used, we’ll blow past that budget by a factor of two,” he said. “The numbers are there, the policy makers are completely ignoring them. They’re saying, ‘we have to listen to the scientists,’ but they’re not. And actually, they’ve stopped saying that now.”

Since Russia invaded Ukraine, the messaging has changed, he added.

“They are talking about building more fossil fuel infrastructure,” he said. “The way it’s going right now, we’re equally dead with Republicans or Democrats. What that says is, we need an uprising. This report doesn’t quite spell that out, but you only have to read between the lines a little bit.”

The most optimistic path identified in the new report shows that it is possible to limit global warming, but only with deep emissions cuts in all economic sectors and in all parts of the world, said climate scientist Bill Hare, who has worked on IPCC reports for decades and is now CEO of Climate Analytics, a nonprofit international climate think tank.

The global temperature will stabilize when carbon dioxide emissions reach net zero, said IPCC Working Group III co-chair Jim Skea. To cap global warming at 1.5 degrees requires reaching net zero carbon dioxide emissions globally in the early 2050s; for 2 degrees Celsius (3.6 degrees Fahrenheit), it is in the early 2070s, he said.

“It’s now or never, if we want to limit global warming to 1.5 degrees Celsius,” Skea said. “Without immediate and deep emissions reductions across all sectors, it will be impossible.”

But even with 1 to 1.5 degrees Celsius of warming, the world faces a great acceleration and intensification of climate impacts like killer hurricanes and wildfires, Hare said.

“We shouldn’t fool ourselves and think we can escape all that stuff, but it will be better the more we limit warming,” he said, reviewing the three IPCC reports released in the past year.

“Working Group I showed the rapidly increasing risks with every increment of warming,” he said. “There are nonlinear risks, like rapid ice sheet disintegration that could raise sea level very quickly.” The Working Group II report “shows that natural systems and vulnerable people are facing massive catastrophes,” he added.

“It’s deeply frustrating that we’re not further advanced,” he said. “I can understand the people who are deeply scared. I can understand people being deeply concerned and panicking about it, but we have to stick with it. It’s all around politics, isn’t it? All of the technology is already there, and we know what to do with it. But at every step, there is pushback from carbon interests,” he said, defining the main problem as the “capture of government by fossil fuel interests.”