The Coldhearted Carbon Math
Ibrahim Rayintakath
Last November in Glasgow, the annual United Nations climate conference ended with its president, Alok Sharma, declaring that the global goal of keeping warming to 1.5 degrees Celsius had been just barely kept alive. “Its pulse is weak,” he said.
This week in Sharm el Sheikh, Egypt, delegates reconvened for COP27, this year’s conference, amid a flurry of confident assertions that the same goal — which has energized and mobilized a global generation of activists and provides the conventional standard for judging progress on emissions — was now dead.
“Say goodbye to 1.5° C,” The Economist intoned on a cover this month, in an edition that called climate adaptation “the challenge of our age” and also raised the specter of cooling the planet with geoengineering. With an image of the flooded Cologne Cathedral — repurposed from a 1986 issue warning of a coming “Klima-Katastrophe” — the November cover of Der Spiegel announced that the target would be missed and advised, grimly: “Save yourself, those who can.” The United Nations secretary general António Guterres, who has spent the past few years raising the rhetorical stakes, declared on Monday that “we are on a highway to climate hell with our foot still on the accelerator.”
This kind of rhetoric, designed to focus attention and clarify the stakes of inaction, can also make things murky. What is the line between climate danger and climate disaster? Or between climate normal and climate disruption, and climate catastrophe and climate apocalypse? Is “climate hell” what awaits us past 1.5 degrees above preindustrial levels, or past 2.0 degrees, or at the level the U.N. expects the world’s current policy commitments to take us this century, 2.6 degrees?
The language is useful as a reminder of the grim impacts to come, but less so as a measure of progress — how much has been done, how far short we are falling, and how much faster we might have to move to reach our temperature targets. For that, we have a much more coldhearted standard: the carbon math, which tells us how much the world is emitting, how much more it can produce while retaining a decent chance of a particular temperature threshold and, therefore, how plausible or implausible each threshold really is.
In 2012, the author Bill McKibben wrote that the math of warming was already “terrifying.” At the time, he was tabulating our emissions against a temperature target of 2.0 degrees Celsius. A few years later, alongside that 2.0-degree goal, the more ambitious target of 1.5 degrees was consecrated in the Paris agreement — the result of several decades of agitation and protest by the world’s most vulnerable countries, which found the prospect of 2.0 degrees intolerable.
We can put much less carbon in the atmosphere to have a chance of 1.5 degrees warming than we could if we were aiming for 2.0 degrees — a principle called the carbon budget, though significant uncertainties surround any estimate of it. And the world has spent the years since Paris setting new emissions records rather than bending the curve downward. There has been reason for optimism and cause for despair over those years, but the math is not a matter of mood or of vibes. It is much more like an hourglass, with 50 gigatons of sand falling through the neck each year.
So what does that math look like now, as world leaders parade across the stage in Egypt, a two-week pageant of taking this seriously? There are at least two ways of looking at the numbers. The first, captured powerfully in the International Energy Agency’s recent World Energy Outlook 2022 report, paints a relatively rosy picture of transformational momentum in the energy transition — things are moving quite fast, indeed faster than most predicted a short time ago, if not quite fast enough to make the Paris targets all that likely. The second, contained in the U.N. Environmental Program’s emissions gap report released just before the conference began, suggests that no matter the speed, the deadlines are uncomfortably close already.
Both sets of numbers are legit. Which means you can tell different stories about the present state of climate action depending on your perspective, inclination, point of ideological emphasis or even mood. In an essay I wrote in October, I emphasized the glass-half-full side of the equation — that the speed of the energy transition meant some of the scariest climate futures (4.0 or 5.0 degrees Celsius of warming by the end of the century) no longer seem nearly as plausible as they did just a few years ago. The recent I.E.A. report illustrates that relative optimism, predicting that fossil fuel use will peak this decade, declaring that the energy crisis sparked by Russia’s invasion of Ukraine has accelerated rather than decelerated the global transition, and finding that global rollout of wind and solar is exceeding earlier projections. Which is all to say: The world is already in the midst of a pretty breakneck green transition, which makes the pathway to 1.5 degrees, the report finds, “narrow but achievable.”
But the glass is also half empty. If there is a significant breakthrough at this conference it is much less likely to be about bending emissions curves and accelerating decarbonization than it is to be about dealing with a world ravaged by climate impacts — establishing some form of institutionalized climate finance for the vulnerable and underresourced nations of the developing world, which have done the least to create the problems they face now and in the decades ahead. These nations are focusing on forms of climate reparations because they are convinced that dangerous disruption is inevitable. Indeed, they are here already, with more and more scientists expressing open fear at the intensity of today’s impact and worrying about what unexpected transformations may await at 1.5 degrees or just above.
That level of warming, and the rate of decarbonization required to achieve it, has provided the architecture for nearly all global ambition undertaken over the past half decade. And how plausible is it in the end? To give the world a 66 percent chance of limiting warming to 1.5 degrees, conventional climate science suggests a carbon budget of 280 gigatons — just seven years of current emissions. Even in its rosy report, the I.E.A. projects that we won’t even reach a peak until later this decade, which means that for much of the next seven years we should expect to be emitting more carbon than we are today. Possibly, the turn could come even later: The I.E.A.’s chief, Fatih Birol, said, “We now see a peak around 2030 for all fossil fuels,” but the projected decline is slow thereafter, with total fossil fuel use not dropping to around 2010 levels until after 2050 in its “stated policies” scenario.
And while cutting emissions more aggressively now would mean more time to ultimately get all the way to zero emissions, what that requires in the short term already looks daunting.
For a 66 percent chance of limiting warming to 2.0 degrees, there is a longer timeline than for the 1.5 target but not much longer; that full carbon budget would be exhausted in 26 years of current emissions. From now, emissions would have to drop globally by 5 percent every year, still a much faster drop than has ever been engineered globally in any year by anything but the Covid-19 pandemic. This is why the climate scientist Glen Peters often says, cheekily, that 1.5 degrees may be impossible and 2.0 degrees only extremely hard, with 2.5 degrees, relatively speaking, “a walk in the park.”
When you look at charts plotting climate promises made by the nations of the world, they tell a relatively reassuring story, with Climate Action Tracker’s analysis suggesting that, if fully carried out, those promises could deliver a global temperature rise below 2.0 degrees, with a central estimate landing at 1.8 degrees.
But those headline promises paper over an enormous amount of sketchy accounting. A separate Climate Action Tracker analysis of 37 countries and the European Union, which account for the vast majority of world emissions combined, finds that none have a climate policy even “compatible” with a 1.5-degree goal. According to the Land Gap report released Nov. 1, global climate pledges by countries require reforestation and other sequestration measures taking up more land than the entire United States — indeed, require using as much land to sequester carbon as is used to produce all the world’s croplands today. The world’s governments are planning twice as much fossil fuel development as would be consistent with 1.5-degree goals, and 93 percent of corporations with net-zero pledges are off track to meet them.
For decades, those worrying about the geopolitics of climate change would often drift into debates about possible enforcement mechanisms, worrying that nations would be simply unwilling to move on their own. The world has changed more recently, with a moralistic model of decarbonization as a necessary burden giving way to a green energy arms race defined by new competition and rivalry. Even so, ambition is woefully lagging, and in a world full of climate promises without any meaningful leadership for carbon-based sanctions, enforcement looks less like planetary governance forcing countries and corporations to move faster than like finding ways to hold them to their promises.
That is the premise of a report delivered to the secretary general in Egypt this week that pointed squarely at the problem of climate hypocrisy — and the delusion that promises and good intentions could substitute for good math.
The greenwashing report, focused on private sector pledges, outlines 10 gold standards, including that companies should not be able to describe themselves as “net-zero-aligned” while continuing to invest in fossil fuels of any kind, buy cheap carbon credits that don’t stand up to independent scrutiny, only reduce the intensity of their work and not the absolute emissions produced by it, and lobby against climate action or participate only in voluntary disclosure protocols rather than more transparent regulatory frameworks.
“You walk down the street, and we have oil and gas companies saying, ‘Guess what. We’re net zero. We’re carbon neutral,’ whatever,” said Catherine McKenna, a former environment minister of Canada and the current chair of the group that wrote the report. “The problem is everyone’s making announcements, there’s billboards, there’s all these things out there. And if you’re a regular person, you’re like, ‘I don’t know. Is that true or not?’”
Whether the United Nations builds a true oversight program for net-zero pledges, as is called for in the report, is an open question, but, McKenna said, “we do need to move to a more rigorous structure for sure.”
“And that goes for governments too,” she went on. “They need to actually not just have targets. They need to actually be having policies that are going to help them reach those targets. And then they’re going to have to be more ambitious,” she said. “You have to be more ambitious.”