Why there’s still a rational case for climate optimism

Kelp
AP Photo/Manuel Valdes
Kelp carbon remover: In this photograph taken April 8, 2016, scientists Joth Davis, left, and Brian Allen, of the Puget Sound Restoration Fund, hold kelp that naturally grew on a buoy line in Washington state’s Hood Canal. An experiment demonstrated the viability and potential of open water seaweed farms in removing carbon dioxide from surrounding waters.

The Supreme Court ruling curtailing EPA’s power to cut greenhouse gas emissions dismayed me and other climate advocates. It was handed down just at the moment when, as UN Secretary General António Guterres said, “The window to prevent the worst impacts of the climate crisis is closing fast.” Current climate goals call for a 45 percent reduction in greenhouse gas emissions this decade — but we’re on track for a 14 percent increase.

That doesn’t bode well for the future. 

Yet rising climate doomism isn’t the answer, either. Even if EPA authority to set limits on greenhouse gas emissions is limited, there is still plenty we can do to reverse the current climate trajectory. “We have the basic technologies now already deployed, to get where we need to in the next eight years to meet the goal of a 45 percent reduction [in emissions],” U.S. special climate envoy John Kerry said at the World Economic Forum in Davos in May.

That’s not only true, it’s grossly understated. Promising climate technologies that exist today could take us a lot further than cutting greenhouse gas emissions by 45 percent.  But even if we cut emissions all the way to net zero by midcentury, which we can and must do, it still won’t make a decisive difference in the climate we’ll bequeath to the next generation — because current emissions are far from the whole problem. 

By far the biggest drivers of global warming today are atmospheric greenhouse gas concentrations, which come from “legacy emissions” — previous emissions which have been accumulating in the atmosphere. That means to strike more than a glancing blow at climate change, we need both to cut new emissions and to scale up greenhouse gas removal technologies so we can lower current atmospheric greenhouse gas levels. 

The most recent IPCC report admitted that relying on some form of carbon dioxide removal will be “unavoidable” just to reach net zero, since we can’t completely eliminate current and future emissions. But removal technologies can and should take us way beyond net zero. There are many promising approaches with the potential to take many gigatons of CO2 and other greenhouse gases out of the atmosphere and restore atmospheric CO2 to pre-industrial levels.

That’s a very different proposition from halving or zeroing out current emissions. Arun Majumadar, head of the new Stanford Doerr School of Sustainability, which just attracted $1.69 billion in funding, got the scale right when he said, “We need to remove tens … if not hundreds of gigatons of CO2 and methane from the atmosphere.” 

On our current trajectory, we are headed to CO2 levels of 450 ppm by 2050 — 50 percent higher than human beings have ever survived long-term. On the other hand, if we stopped emitting greenhouse gases and removed, say, 50 gigatons of CO2 a year from the atmosphere over 20 years, that would lower atmospheric greenhouse gases by a trillion tons. That trajectory leads to restoring the atmosphere to its pre-industrial state by 2050 and reestablishing a safe, healthy climate. Shouldn’t that be our goal?

We’d need a suite of diverse removal technologies to pursue climate restoration on this scale. Fortunately, the field is advancing rapidly, and its growth doesn’t depend on what happens to EPA regulatory authority over emissions. Spurred forward by research institutions like Stanford and a growing finance ecosystem of carbon markets, climate solutions investment, and opportunities like the XPRIZE Carbon Removal Competition, removal technologies are already emerging fast. It’s time to start leveraging them, building them into climate modeling, and factoring them into our ambitions for what kind of climate future we can achieve. 

Rather than geoengineering approaches like solar radiation management, greenhouse gas removal refers to a range of technologies that work with natural terrestrial or ocean processes to capture and store carbon, and are durable (meaning they would sequester carbon for at least a century), scalable (meaning they could reach the 10-gigaton scale within a decade), financeable, equitable in their impacts, safe, and effective. 

For example, synthetic limestone uses a chemical process similar to the mechanism shellfish use to build their shells to pull carbon out of the air and make it into rock. The limestone gets ground up into concrete and permanently sequestered in buildings and roadbeds. As a feedstock for it, synthetic limestone is as financeable as concrete itself. Global concrete demand and usage is high enough that theoretically all the excess carbon in the atmosphere could be captured and sequestered this way.

Cultivating macroalgae in the oceans, such as kelp forests, is another promising removal approach. They grow and photosynthesize rapidly, converting dissolved CO2 in the oceans to oxygen at an astonishing rate. Cultivating them over just 1 percent to 2 percent of the ocean’s surface, especially in deep areas that are currently hypoxic “dead zones,” could restore marine habitat and fisheries, while potentially converting all the excess carbon in the atmosphere. When they die in the deep ocean, instead of re-emitting the carbon into the atmosphere, the plants sink to the bottom, sequestering the CO2 for a millennium. Kelp and other macroalgae products are also marketable as food, cosmetics, and pharmaceuticals. Between that and their giant co-benefit of restoring fisheries, they could attract the financing needed to scale them up.

There are many such examples. Some are more permanent, scalable, or financeable than others, but collectively they represent an emerging body of evidence that greenhouse gas removal could be a viable path forward. It points beyond emissions mitigation, where the effects of climate change won’t be as bad as they might have been otherwise, and towards a restored climate in which people and the planet can thrive. 

The goal of climate restoration is analogous to the goal of net zero emissions, except the time frame is faster, the scale is larger, and the aspiration is higher. It’s not pie in the sky. Since it requires the discipline of selecting and advancing removal technologies that are scalable and financeable, and since it holds out the promise of a future we can aspire to instead of one we fear, it’s arguably the most practical, implementable climate approach we have. 

The Supreme Court ruling limiting EPA authority over greenhouse gas emissions was a significant loss for the climate — but it doesn’t stop governments, corporations, or investors from addressing the main driver of climate change by advancing greenhouse gas removal. And that could be grounds for climate optimism.

Rick Wayman is the CEO of The Foundation for Climate Restoration (F4CR).

Tags Antonio Guterres carbon capture Carbon dioxide removal carbon removal Climate change climate goals Climate restoration climate technologies Environmental Protection Agency geoengineering Greenhouse gas emissions greenhouse gas removal greenhouse gases IPCC report John Kerry kelp forests macroalgae net zero emissions Supreme Court of the United States West Virginia v. EPA
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