Dr John Lynch is a researcher with The Agile Initiative at the Oxford Martin School, where he contributes to a range of environmental research projects, and explores new ways of coordinating policy-related research. He previously worked as a researcher with CO2RE, the Greenhouse Gas Removal Hub, working on sustainability assessment of different carbon removal methods, and is also an Oxford Net Zero associate. In this piece, he reflects on his work with CO2RE and explains what nature-based solutions are and how they can play an important role in responsible greenhouse gas removal.
What are nature-based solutions and how can they help with removing greenhouse gases from the atmosphere?
‘Nature-based Solutions’ are methods to address a societal challenge, like mitigating climate change, that involve ecosystems and benefit biodiversity.
Habitat restoration, in particular, can contribute to climate change mitigation by removing carbon dioxide (CO2) from the atmosphere: the carbon is captured by plants photosynthesizing, and stored in additional ecosystem biomass (especially in the plants themselves, and in soil carbon). Preserving habitats is also extremely important in order to stop carbon being released in the first place (e.g. through deforestation and environmental degradation), as well as maintaining some ‘passive’ carbon uptake. However, habitat preservation has a slightly different role in mitigating climate change to restoration, which is more often thought of as generating additional carbon dioxide removal (CDR). Overall, nature-based solutions have the potential to significantly contribute to keeping global warming to the Paris Agreement targets, but it is crucial that they are deployed in parallel with wider decarbonisation.
For other greenhouse gases (GHGs), particularly methane (CH4) and nitrous oxide (N2O), the situation is a little less clear. While habitat restoration can result in additional removals of these gases through microbiological activity, it can also cause increased emissions, depending on climate and soil type. For example, restoring peatlands (areas with waterlogged soils very rich in organic matter) is important for biodiversity and stops soil carbon losses, but the wetter conditions can also lead to increases in methane release.
It is important to reiterate that directly benefitting biodiversity is a core component of what makes something a ‘nature-based solution’ – so it is not simply a way to refer to carbon/GHG removals that involve biological processes. Some biological removals may negatively impact biodiversity and ecosystem health, and thus would not count. For example, large-scale afforestation (planting trees in areas where they are not the native ecosystem, as opposed to reforestation – returning trees to areas where they were naturally present before human intervention), and growing biomass crops for BECCS (bioenergy with carbon capture and storage) could include ecologically damaging land-use changes. This is not to say, however, that these carbon removal methods are universally bad for nature. In some places, and under appropriate management, these activities could potentially provide ecological benefits – albeit at quite limited scale, and reflecting improvement on a previous, more damaging land use. It very much depends where and how activities are deployed, and there should be a commitment to monitoring and confirming the value of an activity for biodiversity to be recognized as a genuine nature-based solution.
There is an International Union for Conservation of Nature (IUCN) Global Standard for Nature-based Solutions that suggests a more specific set of criteria. It also highlights additional requirements, such as projects needing to be economically viable, and their governance to be inclusive and transparent, benefitting local communities as well as contributing to efforts to deal with broader societal challenges. The concept is therefore more holistic and formalised than many realise from the term alone.
What are socio-ecological systems? Why are they important?
While a nature-based solution to climate change must clearly help mitigate global warming and support nature, it is important to consider these in the context of the wider socio-ecological system: that is, the way in which humans are part of and interact with the ‘natural’ environment.
This is partly, as raised above, because it is important that nature-based solutions are developed in a way that considers the needs of people living locally, and provide tangible benefits for them in addition to carbon removal. We should take this approach so that projects are deployed, and the benefits shared out, in an equitable way. But it is also key because if activities were undertaken without local support, it is unlikely that they would be viable or sustainable into the longer term. For nature-based solutions focused on capturing and storing carbon, long-term management and protection is essential. Otherwise, there is a risk the location will be degraded and any carbon gains lost, with the CO2 returned to the atmosphere.
We also need to consider where and how nature-based solutions, or any other CDR, fit in with wider human systems in order to determine the best role for different approaches in overall climate change mitigation. How will a given carbon removal be funded, and is it viable? Do the removals rely on particular inputs or pieces of infrastructure (things like nurseries to grow saplings for active habitat restoration, or networks of pipes and vehicles for carbon transport)? To what extent is the method sustainably scalable – how much overall carbon removal could be provided?
What has been the most surprising thing to come out of your work with CO2RE?
While most climate change mitigation research agrees that at least some CO2 removal is required, it can be surprising that there is still such a large range in how much removal is deemed necessary, and which methods will be best at providing it. Some of this reflects ongoing scientific uncertainty around individual removals: how successful they will be, the degree to which they can be scaled up, or whether other factors might limit their deployment (for example, biomass supply for BECCS is in competition with land use for ecological restoration and food production). Other considerations which can greatly impact the amount of carbon removal required are how much and how quickly we believe wider systemic shifts can occur, like the decarbonisation of energy supply and reductions in demand. In my opinion, these uncertainties make it important to support research and assessment of multiple removal options, so that a more diverse portfolio is available, and we don’t rely on methods that later prove to be insufficient or are associated with additional negative impacts. This is also why programmes like CO2RE that can take a comprehensive approach and consolidate knowledge across different removal methods are so valuable!
Has your research made you feel more concerned about anything?
A concern is that there is still relatively little data on how and to what degree different CO2 removals might affect biodiversity and ecosystem health, or what other side effects (positive or negative) could be associated with them. Although policy statements and large-scale modelling often highlight the need to implement CDR in a way that minimises other negatives and maximises co-benefits, we don’t really have the data or tools to coordinate and asses this at the moment, as highlighted in a recent CO2RE and Greenhouse Gas Removal Demonstrators (GGR-D) paper. We are trying to spur progress on this by suggesting more comprehensive assessment frameworks that could help improve decision-making.
Have any of your research findings made you feel more hopeful?
There definitely are practices that we can implement – right now – to restore habitats and support ecosystem services, which will also help respond to global warming: both mitigating and adapting to climate change and supporting biodiversity. There are still concerns about the potential reversibility of nature-based removals, and the best way to support these given the need to ramp up long-term geological storage in parallel. I’m hopeful, however, that the growing recognition of the need for carbon removal and ecological restoration will mean we can encourage both without viewing it as a ‘zero-sum’ trade-off in supporting different approaches.
It has also been exciting to work as part of such a passionate and engaged community trying to meet these challenges!
In your view, is there anything the UK government can do (or stop doing) to encourage the adoption of nature-based solutions to climate change?
The first key step that is necessary, in the UK and beyond, is to better integrate climate policy with other environmental goals and decision-making. Otherwise, we could run into the problems highlighted above, getting locked into certain removal pathways that overlook potential co-benefits or, at worst, are actively bad for biodiversity. This will require government to get more serious about meeting its environmental commitments. While the government has set goals on, for example, ensuring clean air and water and thriving plants and wildlife, the Office for Environmental Protection highlights that progress towards them is falling substantially short. The government also needs to do this in a way that brings everyone along – with the buy-in of land decision-makers and public support.
Photo by Patrick Perkins on Unsplash.
