“The scientists told us three years ago that we had 12 years to avert the worst consequences of the climate crisis. We are now three years gone, so we have nine years left.”

— John F. Kerry, special presidential envoy for climate, in an interview with “CBS This Morning,” Feb. 19

Several readers asked us about the accuracy of this statement by the former secretary of state.

Kerry is using a figure that is frequently cited but often misused. It’s a good example of how scientists may write a long and complex report, and then it’s interpreted by the news media, pundits and politicians in ways that make the scientists frustrated that their nuanced conclusions have been twisted into a talking point.

If anything, scientists say, Kerry’s phrasing understates the problem facing the planet.

The Facts

The question of whether humans have contributed to climate change may still be a subject of debate in the political sphere, but it has been a settled issue among climate scientists for years. In 2018, the Intergovernmental Panel on Climate Change (IPCC), a United Nations body, issued a report that said the planet — which has already warmed 1 degree Celsius (1.8 degrees Fahrenheit) above preindustrial levels (approximately 1850 to 1890) — would warm 1.5 degrees (2.7 degrees Fahrenheit) between 2030 and 2052 unless significant steps were taken to reduce carbon dioxide emissions.

Recall that a goal of the 2015 Paris climate accord, which the Biden administration officially rejoined on Friday, is to keep the planet from warming beyond 1.5 degrees. So the report said, with “high confidence,” that global carbon dioxide emissions would need to drop significantly “well before 2030” to meet that goal by mid-century. The report said that “the lower the emissions in 2030, the lower the challenge in limiting global warming to 1.5°C after 2030 with no or limited overshoot.”

All these references to 2030 led to the shorthand use of “12 years away” in media reports. But the key date was 2050, when the gain in emissions needs to be halted — “net zero” — to prevent the planet from continuing on a path of exceeding 2 degrees Celsius. The report’s key finding was that action needed to be taken immediately — not in 12 years.

But somehow, 2030 was interpreted into a point of no return, almost like an on-off switch.

“Slogan writers are vague on whether they mean climate chaos will happen after 12 years, or if we have 12 years to avert it. But both are misleading,” Myles Allen of the University of Oxford, one of the report’s lead authors, wrote in 2019.

“Please stop saying something globally bad is going to happen in 2030,” he added. “Bad stuff is already happening and every half a degree of warming matters, but the IPCC does not draw a ‘planetary boundary’ at 1.5°C beyond which lie climate dragons.”

According to Drew Shindell, a Duke University professor and a lead author of the mitigation chapter of the report, the reference to 2030 was an accident of expediency.

“To save computer time, the research community typically evaluates future climate scenarios every decade rather than every year, choosing multiples of 10,” Shindell told The Fact Checker. “So when we wrote the IPCC report in 2018, we could examine possibilities for 2020, 2030, etc., going forward. There really wasn’t enough time to make changes in economic systems by 2020 starting from 2018, so the first time at which we could see major changes was 2030, and that’s why we could draw conclusions about how much our emissions needed to be cut by 2030 to have much chance of meeting our climate targets.”

Shindell added that “the point of all this is that there is nothing at all special about 12 years or 2030. If we cut emissions by 2029 or 2031, the necessary cuts would be similar, but we only had years that were even multiples of 10 to look at.”

In other words, there is a continuum here — instead of everything bad suddenly happening all at once when the Earth moves from 1.49 degrees to 1.5 degrees.

The IPCC report, for instance, suggests that at 1.5 degrees Celsius, there could be the loss of most coral reefs, the backbone of one of the Earth’s fundamental ecosystems: “Coral reefs, for example, are projected to decline by a further 70-90% at 1.5°C (high confidence) with larger losses (>99%) at 2°C (very high confidence).” In other words, the damage would have already started before 1.5 degrees was breached.

The report sketched disaster if the planet warmed beyond 2 degrees Celsius. But the world is heating unevenly. A Pulitzer Prize-winning Washington Post series showed that, despite an average global increase of 1 degree Celsius, in several parts of the world the 2 degree threshold has already been reached. In those regions, this has resulted in major weather changes that have upended livelihoods and cultures. More than 1 in 10 Americans — 34 million people — are living in rapidly heating regions, including New York City and Los Angeles.

“There’s nothing magic about 1.5C. There’s no climate ‘cliff’ that we go off. The more carbon we emit, the more warming we cause, the more damage that’s done,” said Michael E. Mann, a Pennsylvania State University climate scientist and author of a new book, “The New Climate War.” “If we reach a 50 percent drop in emissions by 2030 we remain on a path with a roughly 67 percent likelihood of avoiding 2C warming, but we have to continue down that path to carbon neutrality by 2050 to realize that scenario.”

Mann said it would be easier to use the analogy of a highway: “We want to get off the earliest exit we can. But if we missed the 1.5C exit, we still work like heck to get off at the 2C exit.”

A. Scott Denning, a climate scientist at Colorado State University, said he found the political fixation with 12 years to be “frustrating.” As he put it, “Every bit of coal, oil and gas burned anywhere adds to the CO2 in the air and reduces the efficiency of Earth’s cooling to space, so every last lump contributes to heating the climate. That was true 20 years ago, and it will continue to be true 12 years from now. And once it’s in the air, it’s not going away.”

Said Daniel L. Swain, a climate scientist at the University of California at Los Angeles: “At this point in time, there is little to no evidence that climate warming, in itself, will become impossible to stop in 9 years. All future emissions reductions will still act to reduce the amount of eventual climate warming, whether they happen tomorrow or 20 years from now. On the other hand, this also means that global warming is already producing severe and harmful impacts around the world at our current level of warming — so the notion we can safely wait another nine years to treat this problem with the seriousness it deserves is also problematic.”

Swain said that if he were to revise Kerry’s comment, he would drop any reference to years and render this way: “The scientists have been telling us for decades that we need to act as fast as possible to avert the worst consequences of climate change. Despite that, substantive action has been delayed so long that we’re now bearing witness to the harm caused by warming that has already occurred in communities around the world. It is still well within our power to turn the tide, slowing and eventually halting global warming by bringing our net carbon emissions to zero. But we have to act now to prevent ever greater societal harm and disruption in the coming years and decades.”

A State Department spokesman provided the following statement to The Fact Checker: “Secretary Kerry was underscoring that the policy decisions we make over the next decade will make all the difference in our ability to get on a path to keep warming to 1.5 degrees or below. As the foreword of the IPCC report states: ‘Without increased and urgent mitigation ambition in the coming years, leading to a sharp decline in greenhouse gas emissions by 2030, global warming will surpass 1.5°C in the following decades, leading to irreversible loss of the most fragile ecosystems, and crisis after crisis for the most vulnerable people and societies.’”

The Pinocchio Test

The climate scientists we contacted appreciated the urgency to address climate change that Kerry expressed in his remarks. He’s correct that the trajectory of emissions needs to be changed. But he stumbled by citing a date for action: 2030. The science doesn’t support a single number of years as the world’s limit but does support the need for rapid and deep emissions cuts.

There are not “nine years left.” Action needs to be taken now to address climate change, according to the report Kerry cited. Moreover, 2030 is not a magic date when future efforts to combat man-made climate change will no longer be effective; it just means that if emissions are not reduced by 50 percent by 2030, the task will become even harder.

As the new climate envoy, Kerry has a specific responsibility to speak clearly about the challenges ahead. With the “12-year” fixation, he somehow managed to both make the task seem less urgent and also more hyperbolic. He earns Two Pinocchios.

Two Pinocchios

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