Stopping climate change isn’t enough — we need to reverse it.
In 1850, when Standard Oil was but a twinkle in the eye of John Rockefeller, the concentration of carbon dioxide in the earth’s atmosphere was 285 parts per million. Today, CO2, the main climate-polluting gas, has jumped to 415 ppm. You know how we got here: extraction, combustion, emission — repeat. And scores of government agencies, international consortia, and environmental groups — along with a gaggle of presidential candidates — say they know how to get us out.
But where, exactly, will all these self-proclaimed climate prophets lead us? Leafing through global plans to save the climate in 2019 is something like reading a choose-your-own-adventure novel — with the stakes of, you know, the future of humanity. At the end of one forking path is an uninhabitable earth, complete with fire tornadoes and mass extinction, and at the end of another is a climate that can still sustain life as we know it. Or so we’re told.
With dozens of climate plans on the table, it’s worth interrogating the extent to which these proposals would actually get us to that livable future (if we can agree on what “livable future” even means). And if none of these plans live up to the promise, we’d better get busy changing the climate conversation.
You’re probably familiar with the 2 degrees Celsius threshold — a politically palatable target for the maximum amount of average global warming we ought to allow to avoid “catastrophic climate change.” We’ve been talking about that threshold since Yale economist William Nordhaus first proposed it in 1975. So far, Earth has warmed about 1 degree above pre-industrial levels.
But last year, scientists released a report laying out the potential effects of just 1.5 degrees C of warming. Even at the lower threshold, we could lose the Greenland ice sheet, as well as 70–90% of coral reefs and 1.5 million metric tons of fish and crustaceans caught to eat each year — to say nothing of the effects on human health and livelihoods.
Does 1.5 degrees qualify as livable? Tolerable? Acceptable? And is it even possible?
The consortium that conducted the 1.5-degree research — the Intergovernmental Panel on Climate Change (the biggest kahuna in climate science, usually referred to by its acronym, IPCC) — also laid out a series of emissions-reduction scenarios that could feasibly limit warming to 1.5 degrees C. In most of those scenarios, we overshoot 1.5 degrees for a time and dial back to 1.5 by 2100. The longer the overshoot lasts, the more trouble we’re in. In some scenarios, we would see irreversible damage to whole ecosystems, such as those rooted in coral reefs.
Even the more ambitious proposals start to look rather tenuous when you put them under the microscope. One IPCC scenario that theoretically limits us to 1.5 degrees of warming, the so-called P2/S1 scenario (the ‘P’ is for pathway) requires a 95% cut in CO2 emissions by 2050 (relative to 2010). Assuming our emissions would fall at a steady rate (they probably won’t, but we’ll err on the conservative side here), and further assuming atmospheric CO2 levels increase directly in proportion with emissions, that means under P2, we’ll hit 452 ppm in 2050. Which is… 50% higher than humanity has ever survived in the long-term.
With that kind of trajectory, we can expect average global temperatures to overshoot the 1.5 degree Celsius threshold by at most 0.1 degrees by mid-century or so. To ratchet back to 1.5 degrees by 2100, the scenario relies on technology and techniques that would suck about 150 billion metric tons of CO2 out of the air, with limited rollout of this technology by around 2040.
Other scenarios require more CO2 removal. Take the P4/S5 pathway, for example, which assumes the greenhouse-gas-intensive lifestyle of the United States continues to spread to the rest of the world and we have to rely almost exclusively on removal to limit warming to 1.5 degrees by 2100. Even under the carbon capture and storage approach of P4, and given the same assumptions as above, we’re left with 461 ppm by 2050 and a temperature overshoot closer to 0.5 degrees.
That’s a little worrying. IPCC researchers are the popular girls of climate science. Their mitigation scenarios reveal a whole host of dreams the rest of us project onto the world — a certain mainstream consensus about what we ought to be eating and wearing and, like, keeping in the ground.
But these pathways certainly don’t get us to safe pre-industrial levels of CO2. And remember, with 1.5 degrees of warming, we’re still left with 80% of Greenland turning into a puddle and the collapse of whole marine ecosystems.
Let’s get radical
But fine; those pathways came from the cool kids at the IPCC — not, say, the skateboarding eco-socialists of the climate world. So what about them?
The Green New Deal resolution sponsored by Representative Alexandria Ocasio-Cortez and Senator Ed Markey, calls for net-zero emissions by 2030. Applying the same methodology as above (and extrapolating the proposal to the scale of the world instead of just the United States), the 2030 goal implies a concentration of 428 ppm — just a bit more than where we’re at now. But certainly not less. There’s no serious climate modeling consistent with a theoretical worldwide Green New Deal, but generally, the approach is consistent with 1.5 degrees of warming by the end of the century, suggesting no great improvement over the IPCC’s latest work in terms of climate impact. The resolution has 94 House and 12 Senate co-sponsors, as well as a whole army of nay-sayers, but it might not go far enough.
What about Drawdown, “the most comprehensive plan ever proposed to reverse global warming,” rolled out by author and activist Paul Hawken and his team in 2017? The story here is more or less the same as P2: net-zero by 2050, suggesting a CO2 concentration of around 452 ppm and temperature increases of 1.5 degrees over pre-industrial levels by 2100.
Even the improbable political posturing around climate change in the Democratic primaries doesn’t bring theoretical concentrations of the gas below where it is today anytime soon. Washington State Governor Jay Inslee, the self-proclaimed climate candidate, argues that the global community must heed the IPCC’s warnings and reach net-zero by mid-century or even earlier: by 2045. Subjecting it to the same analysis as above, and assuming the world all got on board the 2045 deadline, Inslee’s plan leaves us with… 446 ppm by 2050. Better than the IPCC pathways; not quite as bold as the bolder variants of the Green New Deal.
The long and short of it all is that if you’re interested in returning to a natural climate equilibrium, you’ve got to find a plan that does more than just reduce carbon pollution. It has to aggressively reverse it, taking the world back to 300 ppm or lower — the levels the world knew in the pre-Standard Oil days. Not just climate mitigation: climate restoration.
Back to the future
Is a sub-300 ppm goal really so audacious, given the rest of human history? It has taken us less than 200 years to get to where we are today. Surely, given the vision, the technology, and the will, we could wind back the carbon clock.
“Climate restoration is the natural next step on our climate journey, building on the mitigation and adaptation work that’s been underway for decades,” says Dr. Erica Dodds, chief operating officer of the Foundation for Climate Restoration. Dodds argues that a restored climate is not only possible, but morally required of us. “Today’s youth are afraid for their futures and are planning for a dystopian planet. Restoring our climate isn’t a philosophical question. It’s a concrete, urgent, moral obligation.”
That’s the whole paradigm shift in a nutshell: Even net-zero climate plans come up short unless they pull a trillion tons of CO2 out of the atmosphere. (Without aggressive carbon removal, natural reabsorption of extra CO2 would take thousands of years.)
It’s a curious political frame, that which describes plans permitting 450 ppm as ‘bold’ and ‘ambitious.’ Are plans seeking a proven, safe 350 or 300 ppm merely laughable? Or are we simply suffering from a failure of imagination — blinded, perhaps, by the momentum of the status quo?
It’s no secret that politics constrains what’s possible. But we can’t let it constrain our vision. Until we start thinking seriously about restoration, we’ll be on the road to a hotter, hellish world. We shouldn’t need to go back in time to find a healthy climate.
This article is sponsored by the Foundation for Climate Restoration, a nonprofit partnering with local governments, NGOs, and communities around the world to launch Climate Restoration projects at scale. Its Healthy Climate Alliance is an education, networking, and advocacy program to advance these goals.
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