The key passage in the 2018 UN agency report that set countries on a path to a 1.5°C limit on average global warming is gaining recognition as one of the most influential bits of text in human history.
Not quite 2½ years after its release, renowned energy historian Daniel Yergin is putting the operative sentence from the 1.5° pathways report issued by the Intergovernmental Panel on Climate Change (IPCC) in a kind of pantheon, on a par with “all [people] are created equal”, Bloomberg Green reports. Bloomberg reporter Eric Roston adds another memorable phrase to the mix, given the existential nature of the climate crisis: “to be or not to be—that is the question”.
“I think you could say that [the IPCC language] is one of the most important sentences of the last few centuries,” Yergin said. “It has provided an incredibly powerful traffic signal to tell you where things are going.”
The sentence itself would strike most of us as unassuming: “In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40-60% interquartile range), reaching net zero around 2050 (2045-2055 interquartile range,” the IPCC stated.
“Like most statements the IPCC sets down, the most important sentence ever written is just terrible—clunky and jargon-filled,” Bloomberg writes. But “what it says, in English, is this: By 2030 the world needs to cut its carbon dioxide pollution by 45%, and by mid-century reach ‘net-zero’ emissions, meaning that any CO2 still emitted would have to be drawn down in some way.”
The impact of those few words has been dramatic. “The portion of the report outlining the 2050 timeline was just a single sentence, and yet very few corners of the world have remained unaffected by it,” Bloomberg says.
“Two years later, eight of the 10 largest economies have pledged to reach net-zero emissions by mid-century—nine once President Joe Biden formalizes his campaign promise to do so. Twenty-nine countries, plus the European Union, have net-zero pledges for either CO2 or all greenhouse gases, accounting for 14.5% of global emissions. Some 400 companies, including Microsoft, Unilever, Facebook, Ford, Nestlé, PepsiCo, and Brunswick Group, have signed on with the Business Ambition for 1.5°C pledge, which is built on the IPCC’s analysis.”
Kelly Levin, senior associate in the World Resources Institute’s global climate program, said many of the national targets “are very much driven by the latest climate science,” though she cautioned that some nations will have to move faster than others. And all the national programs will have to factor in greenhouse gases like methane and nitrous oxide, in addition to the CO2 emissions that were the focus of the IPCC report.
“The spirit of the Paris Agreement is to increase ambition continuously,” she told Bloomberg, and “countries with the highest emissions, greatest responsibility, and capability should adopt the most ambitious target time frames.”