The State of Carbon Dioxide Removal report is one of the first independent assessments of how much carbon dioxide is currently being removed from the atmosphere, and how much more needs to be removed, year by year, to stabilize greenhouse gas levels by mid-century. It is an important contribution to the climate conversation and a topic that will receive more attention in the future.
But here the report misses the mark: It underestimates Mother Nature’s vast potential to do the decarbonization work herself. And in the same vein, it fails to acknowledge the growing limits of technological innovation that can help and dramatically amplify the power of natural climate solutions.
The Oxford report’s authors call for a strong scaling up of “new” carbon dioxide removal strategies. These range from low-tech biochar and biofuel production with carbon capture and storage, to more imaginative alternatives such as mechanical trees and other machines designed to absorb carbon dioxide from the air and convert it into carbon bricks, or other storable forms. The report concludes that CO2 removals from new technologies should increase “by a factor of 30 by 2030 … and by 1,300 (even about 4,900 in some scenarios) by mid-century.”
While I am very supportive of new investments in climate-smart technology—I celebrate them routinely in this column—we’re still years if not decades away from developing machines that can perform carbon dioxide removal on a scale even approaching what nature can do. Billions of dollars are being invested in so-called direct air capture technologies (mechanical trees and the like), but none of them have yet been successful on a large scale.
Meanwhile, well-managed forests, grasslands, and farms currently remove and sequester billions of tons of carbon dioxide from the atmosphere each year via photosynthesis. Exactly how many billions is up for debate. The Oxford University study says that terrestrial ecosystems currently remove 2 billion tons of carbon dioxide annually and estimates that this number could double to 4 billion by 2050. But this is less than the lower end of potential removal estimates cited by the Intergovernmental Panel on Climate Change, which predicts that terrestrial ecosystems could eliminate approximately 5 billion to 8 billion tons of carbon dioxide from the atmosphere annually by 2050, simply by improving land stewardship practices.
Trees and crops perform a kind of climate miracle from lemons to lemonade because they breathe carbon dioxide through their leaves and convert it not only into useful materials like corn, cotton, and wood, but also through their roots in the ground, where carbon becomes the lifeblood of fertile soil.
Almost all of the successful carbon dioxide removals to date have come from natural climate solutions such as forest protection, tree planting and improved soil management, Gregory Nemet, a co-author of the report “The State of Carbon Dioxide Removal” and professor of public policy at the University of Wisconsin at Madison, told me. So I asked him, “Why don’t you invest heavily in it?” In my view, supporting and expanding the extraordinary potential of natural ecosystems to perform decarbonization is what investors and policymakers should focus on – not fancy machines.
The premise of the report, Nemet said, is that “there is a limit to what nature-based climate solutions can do.” But I see this limitation as a failure of creative thinking.
First, it assumes that we will adhere to current land-use patterns, which are heavily skewed toward agriculture: farmland currently covers more than half of the United States and about 40% of the global land area. The vast majority of this land is dedicated to grain and traditional livestock production. But a combination of new technologies and policies could make it possible to grow more food on much less land. Land freed from agricultural use can be reforested and reforested – thus turning billions of tons of carbon pollution into living ecosystems.
There is no doubt that better management of forests and farmland can dramatically reduce atmospheric warming even over the next decade – furthermore, dramatically more carbon can be removed from the atmosphere if we invest in technologies that support and amplify the power of nature. (Disclosure: My brother Bronson Griscom co-authored a major study on natural climate solutions and leads ongoing research in this area for Conservation International.)
The biggest challenge with these natural solutions is that they are delivered by a complex set of ecosystems spread across the Earth. It is critical to develop a low-cost monitoring technology so that this vast network can be scaled and managed. Remote monitoring systems, including satellites and radar that can track changes in land use in increasing detail, can go a long way to help, as can devices that hang on trees to monitor carbon sequestration rates.
Investors and policymakers should also support the development of microfinance systems that can reward people with the richest forests—mostly in tropical countries—for the sustainable management of these essential carbon sinks. Some will be compensated for not cutting down trees. Other money will be paid to sustainably manage agroforestry operations and harvest trees in a way that benefits the long-term health of the forest. This would be a much more sophisticated system than PayPal, one with software that monitors and evaluates complex indicators of ecosystem health and makes payments accordingly via cellphones held by farmers and forest managers in the field.
Above all, we need to invest in climate-smart farming technologies from AI tractors and robotic weeders to vertical farms and GMO and CRISPR crops designed to withstand increasingly stressful growing conditions. I also have great confidence in shifting towards regenerative farming practices that can significantly increase fertility and the ability to sequester carbon dioxide in the Earth’s soil. There is huge potential for changing land-use patterns on a large scale through the creation and adoption of demand-side technologies – most notably meat alternatives such as plant-based and cultured meat products that require significantly less land to produce high-quality proteins.
Let me be clear that I am not opposed to the remote technologies espoused in the Oxford University report. Some important progress has been made recently by Swiss company Climeworks, for example, and Canadian company Carbon Engineering in developing machines that work like giant carbon dioxide brooms. In the long run, we need all the solutions we can get, both from machines and nature.
But our climate clock is ticking, and right now we must focus our energy and investment on the most appropriate path. For a long time, climate advocates have resisted discussing carbon dioxide removal for fear it would distract from the urgent need for emissions mitigation. We certainly cannot let polluting industries off the hook. But we cannot ignore the importance of decarbonization any longer. Nor should we focus too much, in the near term, on carbon absorption machinery.
The way forward requires humility. And if climate change has taught us anything, it’s that nature is smarter and more powerful than we are. It’s time to admit that the killer app for carbon dioxide removal is Mother Nature. Let’s invest in it.
More other writers on Bloomberg Opinion:
• Cities would literally be cooler with more trees: Lara Williams
• Global Warming Tests California’s Innovative Spirit: Fay Flame
• How will geoengineering work? Look at Game Theory: Tyler Cowen
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
Amanda Little is a columnist for Bloomberg Opinion covering agriculture and climate. She is a professor of journalism and science writing at Vanderbilt University and the author of The Fate of Food: What We Will Eat in a Bigger, Hotter, Smarter World.
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