The world is on a dire climate path, and the commitments of global governments to curb greenhouse-gas emissions are still woefully insufficient to blunt dangerous warming. That’s the takeaway from the latest report by the Intergovernmental Panel on Climate Change, the United Nation’s climate agency, released Monday morning. The U.N. secretary general, António Guterres, called the report “a code red for humanity.”
The IPCC report — the sixth major assessment since the panel began its work in 1988 — does not include much new science but is notable for its clarity and bluntness. Many of the changes humans are setting in motion, the IPCC warns ominously, are likely to be “irreversible for centuries to millennia.”
The report underscores that the evidence of climate change is all around us, already driving “weather and climate extremes in every region across the globe” including “heatwaves, heavy precipitation, droughts, and tropical cyclones.” The U.S. this summer has seen evidence enough of that, with record-shattering heat waves and expansive drought and wildfire throughout the west.
The 2015 Paris climate accord seeks, as an ambitious target, to limit warming to 1.5°C above preindustrial levels, while vowing to constrain warming to “well below 2°C.” But the commitments to date by the world’s governments “are insufficient” to assure either target, the report says. Indeed, both the 1.5°C and 2°C thresholds will be breached this century “unless deep reductions… occur in the coming decades.”
According to the report, the 1.5°C future is now all but assured, even under the lowest emissions scenarios modeled by the U.N. agency. Securing that best-case scenario would require complete elimination of carbon emissions by 2050.
The difference between 1.5°C and 2°C warming may seem marginal to the lay person. But the IPCC published a special report in 2018 that made clear that the extra warming of a 2°C world could have catastrophic consequences — exacerbating threats to “ecosystems, human health and well-being.” (Read Rolling Stone‘s analysis of that report here.)
The new report emphasizes that each “additional 0.5°C of global warming causes clearly discernible increases in the intensity and frequency” of heat waves, heavy precipitation, and drought. For example, a heat event that would have been expected to occur once in 50 years prior to human-induced warming is already five times more likely to occur at current warming levels (about 1°C). But the IPCC projects that such a heat event would be 8 times as likely at 1.5°C of warming, and nearly 14 times as likely under a 2°C scenario. At an unchecked 4°C of warming, the risk becomes a whopping 39 times worse. That future is a possibility. The IPCC report projects a range of possible temperature increases, from a best-case 1.4°C to a worst-case 4.4°C by 2100.
The IPCC report lands as the House and Senate are weighing trillion-dollar investments in the nation’s infrastructure, seeking to lower greenhouse-gas emissions through investments in technology such as electric cars and a modern electricity grid powered by renewable sources. Democratic Sen. Ed Markey, a proponent of the Green New Deal, described the IPCC report as a “final warning to the world.” Markey added: “If senators truly followed the science in this report, we’d have 100 votes for climate action to match the 100 percent certainty that human-caused climate change is destroying our planet.”