Giving Up on Limiting Warming to 1.5 Degrees Celsius Is a Luxury Only the Rich Can Afford

Climate circles have been quietly humming in the past couple of weeks with a dangerous conversation: that maybe, just maybe, it’s time to give up on limiting global warming to 1.5 degrees Celsius and switch instead to a goal of limiting warming to two degrees Celsius. At COP 27, the United Nation’s climate summit in Egypt, negotiations closed Sunday with a silver lining—that rich nations, including the United States, would help fund an institution to address climate-related loss and damage in vulnerable nations. But talk of switching to a two degrees Celsius goal target casts a pall over this news, suggesting that global commitments to climate justice remain patchy at best.
 
Like all forms of climate defeatism, giving up on 1.5 degrees Celsius (2.7 degrees Fahrenheit) is a conversation for the privileged: 1.5 degrees of warming will already cause vast destruction to climate-vulnerable places, such as communities reliant upon coral reefs. For many more parts of the world, an additional half-degree of warming is the difference between losing one’s house and losing one’s homeland. Unlike the climate threats faced by the wealthy, including the dignitaries and well-heeled NGO staff at COP27, the question for these communities boils down to survival, not strategy. 
 
This statistical hand-wringing has been a long time coming: Rich countries’ delay in instituting serious emissions-reducing policies in the past few years has made meeting the 1.5 degrees goal increasingly unlikely. But the brass tacks conversation had been deferred until The Economist published a cover story two weeks ago, titled “Say Goodbye to 1.5°C.” It was a like dam bursting. Scientists and climate leaders began arguing that shifting to two degrees Celsius (3.6 degrees Fahrenheit) would bolster the movement’s credibility. An open letter released in September and signed by more than 1,000 academics states, “There is no plausible pathway to 1.5°C.” In a Slack thread, a colleague of mine warned of “reputational risks to not adjusting our language/goals to the facts on the ground.”
 
What are those facts? The world will almost certainly exceed 1.5 degrees of warming in the next 30 years. Earth has already sustained a full degree of warming. To avoid adding more than another half-degree would require a global coordinated push. It’s not technically impossible, but it seems at odds with the tepid climate politics of 2022. So 1.5 degrees of warming will likely arrive by the middle of the century. The question is: Should humanity march instead to the two-degrees finish line (which would still require aggressively bending the curve of global emissions) or fight tooth and nail to regain the lost ground? 
 
The Intergovernmental Panel on Climate Change, the world’s leading authority on climate science, wrote a special report in 2019 on the importance (and difficulty) of limiting warming to 1.5 degrees Celsius. The report found that the additional half-degree of warming between 1.5 degrees and two degrees could melt an area of permafrost the size of Wyoming. It would increase the likely incidence of an ice-free summer in the Arctic Ocean from once per century to once per decade. The estimated loss of the planet’s coral reefs would increase from 70 to 90 percent, at the 1.5 degree mark, to more than 99 percent at the two-degree mark. The number of people experiencing climate-induced water stress could double. 
 
These impacts pose a limited risk to the globe-trotting few. For most of the attendees at COP27—which included a staggering number of fossil fuel lobbyists—coral reefs are for snorkeling, sea ice is for polar bears, and water stress means turning off the sprinklers in the front yard. With relatively little on the line, it’s easy for this demographic to couch their arguments in the language of “strategy” and reputational risks. 
 
But climate change is not a one-way road. Moreover, many repercussions from two degrees of warming, including sea level rise, will unfold over generations. Even in 2050, there will be time for humans to put fossil carbon back in the ground where it belongs, and in doing so avoid the most catastrophic climate hazards.
 
The IPCC calls this strategy the “overshoot,” and it’s become the linchpin of its preferred roadmap to climate stability. In an overshoot scenario, global temperature will rise above the horizon of 1.5 degrees Celsius for a decade or two, before dipping back again. The overshoot requires negative emissions: taking carbon dioxide out of the atmosphere and returning it to the soil, oceans, and bedrock. 
 
Carbon dioxide removal is well studied, and while direct air capture technology remains wildly expensive and mired in controversy, low-tech solutions are abundant and cheap. These range from changing farming practices to burying seaweed. But despite a torrent of start-ups flush with venture capital, the simplest and most cost-effective way to remove atmospheric carbon remains converting land used for animal agriculture to healthy forest.
 
Turning back the clock on global emissions is essential to keeping the dream of 1.5 degrees alive. It’s not giving up on a goal; it’s doubling down on one. (It’s also the raison d’être for the “net” part of “net zero,” which otherwise merely serves as a way for corporations to claim climate-friendliness while pushing emissions reductions off into a hypothetical future.)
 
The climate movement’s latest numerological debate is evidence of a poorly kept secret: These goals are the product of politics as much as science. The truth is that there is no “safe” level of climate change, only degrees of damage. If we are committed to climate justice, we must let the most vulnerable set the agenda for the most privileged—not the other way around.