The Tradeoffs Between Engineered and Nature-Based Solutions to Climate Change
One of the most common conversations that has come up in my time working in the regenerative agriculture space is comparing “carbon farming” and other nature-based solutions (including forestry projects, mangrove restoration, and other projects focused on preserving and enhancing natural ecosystems through proper management) to “engineered solutions'' like direct air capture, various forms of CO2 mineralization, and carbon capture and storage built into industrial systems. In essence, it’s a flawed paradigm in many ways because the array of nature-based and engineered approaches is a continuum - not a binary. New technologies are emerging that both enhance a natural ecosystem’s ability to store carbon and perform ecosystem services while relying on human engineering. This being said, the nature-based/engineered framework allows us to understand the carbon markets’ potential reductionism, the need for decentralization and small stakeholder empowerment, and the underlying significance of the time value of carbon.
The value propositions and “sales pitches” of nature-based solutions and engineered solutions seem pretty antithetical to one another. Nature-based solutions typically emphasize community engagement and equity, rapid deployment to scale, and co-benefits to carbon; engineered solutions promise millennia-long permanence, precise carbon accounting, and industrial re-purposing of atmospheric carbon. While engineered solutions are gaining steam in private markets and public financing (be it the section 45Q tax credit for carbon capture projects or Airbus’s 400,000-tonne purchase of DAC credits), investment in nature-based solutions has historically lagged. Nature-based solutions can deliver between 30%-37% of the emissions mitigation needed to stabilize the climate by 2030 - and yet the sector only receives between 3% of mitigation funding as of 2017 and 8% of public climate finance as of 2021.
The best case I’ve heard for favoring engineered solutions boils down to this: there are unique attributes that engineered solutions make attractive to private investors. Those who perfect direct air capture will own the intellectual property to a uniquely scalable infrastructure with minimal land use and few other stakeholders beyond buyers. Nature-based solutions typically require the buy-in of landowners, operators, local and national governments, and other stakeholders. Additionally, engineered solutions tend to be hyper-focus on carbon as opposed to co-benefits that have not yet been commoditized in markets or even standardized in measurement. The carbon stored is also increasingly permanent, displaces no production(no leakage), and would not have happened with carbon finance(is additional) - hitting the triad of performance metrics needed in the carbon credit world. Thus, while conservation projects that rely on nature might be more self-sustaining, the clear return on investment and the fact that engineered solutions are still in their infancy mean that an investor, at first glance, should allocate capital into engineered solutions.
But this isn’t the full picture, and many of the perceived risks implicit in that argument are what make nature-based solutions uniquely tailored to tackle the “triple planetary crisis” of climate change, nature and biodiversity loss, and pollution and waste that we are facing. Nature-based solutions can remove a substantial amount of carbon in the atmosphere, be it through soil carbon farming, silvopasture, or properly done reforestation, and address the environmental issues beyond carbon. This can happen much more quickly than scaling direct air capture, giving it a leg up over engineered solutions in the time value of carbon storage. The emergence of tonne-year accounting and equating the permanence of nature-based credits with engineered ones allows for concerns about permanence to be assuaged while emphasizing the time value of carbon. A systems-level approach that shifts our commodity production systems to be regenerative (i.e. soils and ecosystems being healed) and create networks of conservation can still have great returns, especially for startups focused on aggregation, measurement and verification, and optimizing practices. The number of stakeholders involved, with proper buy-in and clear monitoring, can actually create resiliency and momentum. Carbon reductionism can become increasingly burdensome - and we should seek to avoid it whenever possible.
Of course, finding a solution is more complicated. Scaling up to the $8tn needed to invest in nature will require a mixture of funds from conservation-focused groups, new ecosystem service markets beyond carbon credits, carbon credits themselves, and proper government funding when necessary. In particular, those ecosystem service markets that are still being ideated will serve a key distinguishing feature from the engineered carbon solutions that service one singular purpose. Indeed, we still need to find ways to compensate land stewards that bring back crucial biodiversity and water quality or folks investing in oyster restoration. Right now, that’s only an add-on to carbon markets through certifications like CCB or a consumer-facing label certification. This is not to mention the effects that nature-based solutions have on climate resiliency and the ability to endure extreme weather events. Creating a market-based narrative that incorporates the necessity of co-benefits and the structural advantages of nature-based solutions will lead to a more balanced distribution of capital.
However, new technologies are emerging that essentially enhance nature’s to store carbon. On the list of Carbon Brief’s top ten negative emissions, I picked a few that don’t fit a clean nature-based/engineered divide. For instance, the application of biochar is gaining steam (just see how prevalent it is in Microsoft’s latest carbon removal purchases). Enhanced weathering, when applied to agricultural lands (as we have previously explored here), can lead to productivity gains. Blue carbon, and in particular the sinking of kelp in the deep sea, promises the permanence of an engineered solution by leveraging photosynthesis, also fits in this in-between category, though it is fraught with its own issues in measurement. The Salk Institute’s Harnessing Plants Initiative is designing plants to suck carbon out of the atmosphere. All this is to stay: the lines between nature-based and engineered will continue to be blurred more and more.
I’m personally quite excited by all the entrepreneurial and scientific talent flowing into carbon removal, and I hope that it doesn’t end with carbon. Nature-based solutions promote synergies with sustainable development goals. Historical myopic solutions like ethanol have led to worse ecological outcomes and more carbon emissions after implementation and years of quality research - we should endeavor not to put all our eggs in baskets like that one. I encourage you all to check out the variety of solutions available from carbon brokers like Patch and I applaud corporates like Amazon that are investing billions in both the development of technologies to reduce carbon and help preserve the natural world. Now is the time to invest.
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