Meeting the goals of the Paris Agreement requires the deployment of carbon removal technologies at scale. The generation of ‘negative emissions’ can rely on natural processes, such as forestation or soil carbon sequestration, or human-engineered technologies, such as carbon capture and storage from combusting of fast-growing bioenergy plantation (BECCS), enhanced weathering, mineral carbonation, or the direct capture of ambient carbon dioxide (DACC). While there are differences in their mitigation potentials, risks and maturity, these are all viable options to remove carbon dioxide from the atmosphere and store it in biomass, soils, oceans, or geological formations in the long term.

Additional carbon removal depends on support and subsidies, and carbon finance has been proposed as a mechanism to drive investments in negative emissions. Increasingly, engineered carbon removal technologies are pitched against nature-based solutions and forests, and some see technology as the preferred solution. Corporates with science-based targets may be expected to neutralize residual greenhouse gas emissions with carbon removals that are permanent at a timescale of several hundred years and more, and think tanks such as the New Climate Institute support carbon finance for geoengineered negative emission technologies while dismissing nature-based solutions as suitable for carbon markets.

Any effort to reduce carbon concentrations in the air is welcome. However, a tech-driven plan that establishes a clear preference for carbon finance to go towards engineered solutions at the expense of nature-based carbon removals is misguided and potentially dangerous.

Technologically Stored CO₂: Superior Carbon Credits?

Carbon markets are increasingly proposed as a mechanism to subsidize technological carbon removal solutions. Bill Gates – a fierce believer in DACC – compensates his personal emissions at $600/ton of carbon dioxide captured by an Icelandic DACC start-up (as a bulk investor he gets a discount to the $1,200 offered to subscribers on the startup’s website). But the support for engineered solutions extends beyond tech entrepreneurs.

Experts and NGOs that are skeptical of forest carbon markets are discovering that they are more apt to support carbon offsets from engineered carbon removal solutions. They favor technology over nature because they believe technological solutions have methodological certainty and are permanent, additional, and with limited leakage risks. For many economists and engineers, technological solutions seem more manageable compared to natural solutions and, due to their high costs and single purpose of pursuing carbon removals, are unquestionably additional.

Technological solutions also are tempting as they do not require any engagement with complicated ecosystems or support from local communities. However, technological carbon removals also come with their own set of problems. BECCS, if deployed at scale, potentially requires enormous amounts of land and yield limited to no social or environmental benefits beyond storing carbon. DACC still requires large amounts of electricity, causes air pollution, and the enormous amounts of materials and energy needed may make it difficult to meet expectations of sucking gigatons of carbon dioxide out of the air. And capturing carbon – if used to enhance oil recovery or converted into carbon-based fuels, may only delay the decarbonization of our economies and a transition to a net-zero future.

Unlike nature-based approaches, technological solutions remain unproven at scale. But more importantly, engineered solutions contribute little towards a transition to sustainable societies. In fact, the promise of a future technological fix risks locking in current unsustainable economic systems.

The Permanence of Nature and Technology

While individual trees may be lost, the world has maintained forests for millions of years. If biological carbon storage is correctly incentivized, the world can – and according to the Intergovernmental Panel on Climate Change must – maintain and expand the biological storage potential from nature permanently in order to avoid further local and global climate havoc.

But there is no doubt: Natural systems are vulnerable, and the nexus of human-natural interaction is complex. Carbon stored in forests, coastal ecosystems, or agroecological systems, is vulnerable to reversals in that it can be released due to human-driven deforestation and/or natural disturbances (i.e., fire, floods, pests, diseases, landslides). And even climate change will further heighten the risk of carbon removals. For example, where regions become hotter and drier, forests may become more vulnerable to disturbance and change. This means that offsetting fossil fuels with carbon stored in ecosystems can be, indeed, risky.

However, excluding biological carbon from carbon markets fails to recognize the well-tested methods that credibly address permanence and leakage risks with sufficient certainty. Carbon market standards have formulated and refined permanence rules that assess risks and require mandatory participation in insurance mechanisms—most commonly in the form of buffer accounts. Such mechanisms transfer the permanence risk from one project to a large pool of projects. Projects contribute a share of their carbon credits to a buffer pool and, should reversals occur, an equivalent number of credits are canceled to secure the permanence of issued carbon credits. Buffer accounts do not protect the forests, but they safeguard the environmental credibility of carbon credits. For example, the massive forest fires in Brazil in 2019 and their impact on carbon projects only required the cancelation of a small percentage of reserve credits held in the buffer account that Verra administers for forest carbon projects.

Technology has the lure of being a controlled solution and sealing captured carbon underground may well result in long-term removals of carbon from the atmosphere. However, it is unclear how stored carbon can be monitored and, unless fully mineralized, permanent storage in geological formations is also not guaranteed and the perverse impacts caused by natural disasters are unclear. But more importantly, technological solutions should not replace, but rather they should complement, urgently needed investments in natural solutions.

Nature: Undervalued?

The restoration of natural ecosystems and natural forest restoration also remains undoubtedly additional in carbon market terms. Restoring forests depends on patient capital that accepts long-term returns which put such investment at odds with short-term investment expectations. Technology solutions, in contrast, need near-term R&D investment, but the hope is that once the technology is mature, it can be replicated and rolled out quickly and cost-effectively.

Investments in natural forest restoration are commercially unattractive. They are risky and returns are low. In developing countries where they are most urgently needed, they are also challenged by insecure land tenure and higher reversal risks. As a result, even though the carbon market for nature-based solutions is growing rapidly, the restoration of natural forests does not sufficiently benefit from the growing interest. Even though the opportunity is enormous: Enhancing carbon removals in soils, restoration of peatlands and coastal wetland can -starting today- annually remove over 6 billion tons of CO₂ per year across 79 tropical countries and territories between 2030 and 2050 at a cost of less than US$100 per tCO₂e – significantly less than the price tag of $600 – $1,200 for DACC.

Unlike technological solutions, the restoration of ecosystems and agroforestry can contribute to halting the loss of biodiversity, increase soil fertility and improve water quality. The world’s forests also produce the oxygen we all breathe and help regulate local and global weather patterns. Halting deforestation and restoring forests in recently deforested areas is also the best chance we have to avert a tipping point for the Amazon system. If current deforestation rates continue the Amazon system will flip before long to savannah ecosystems in eastern, southern, and central Amazonia. It is impossible to fully grasp the consequences of a land-use change at such a scale.

Nature vs Technology, or Nature & Technology?

Our lives depend on biologically stored carbon. At some point, our lives may also depend on storing carbon in geological formations to avert catastrophic climate change, but it is hard to compare the benefits of technology over nature. Technological solutions do not deliver the same co-benefits – and clearly cannot substitute for the loss of forests and ecosystems even though some argue technological solutions should replace biological ones for offsets. Setting one mitigation solution against another is dangerous, as all options to mitigate climate change need to be on the table. But holding out for technology to produce a superior solution is also dangerous – particularly if it discourages investments into nature-based solutions in general, and the restoration of natural forests in particular.

Carbon markets are not a universal solution to finance forests, however, they are a start and often the only opportunity to channel private finance into ecosystem restoration. While most of the finance for technological solutions will flow to companies in rich countries, investments in nature-based solutions can benefit poorer countries and communities. Indigenous and rural communities are the stewards of many globally critical ecosystems, and for them, investment in nature is the only option to protect and restore their forests.

At a moment of awakening for nature-based solutions, it seems dangerous to label biological removals as second-class carbon credits. Nature has a history of being left out of carbon markets and is only now starting to ramp up and achieve entry into the club of ‘investable’ carbon solutions. Nature cannot be shown out the door again and left to find ways to attract investment – we are out of time, and there may not be a “next time”.