News

Wanger et al. 2020

Tsunamis have claimed over 260,000 lives this last century, making them the most deadly of natural hazards. In 2018, a tsunami devastated the Indonesian city of Palu and in response the government is planning to build a 7km long, 3.2m high sea wall. This paper suggests a hybrid coastal protection strategy for Palu instead, which combines ecological disaster risk reduction with traditional engineering. Although sea walls are often seen as the most effective form of coastal protection, the authors outline the disadvantages: they are expensive, induce a false sense of security, and can interfere with natural processes like sedimentation, which leads to degradation of natural habitats like mangroves. The paper discusses how ecosystem-based and hybrid approaches can combat these issues. For Palu, the authors suggest that coral reef and mangrove rehabilitation would be appropriate for contributing to dissipation of future tsunamis or storm surges. Palu can act as a case study to investigate how an eco-disaster risk reduction approach can reduce costs from storm surges whilst also improving biodiversity, helping to inform similar projects across the tropics. Read more here.

Together with Oxford colleagues, Michelle Cain and Michael Obersteiner, Nat Seddon took part in a roundtable meeting at the Palace of Westminster to discuss “Achieving Net Zero: The Role of Land” with the Net Zero All-Party Parliamentary Group (APPG). Over the course of two hours, they discussed policy and science issues on what it will mean, and what it will take, to achieve Net Zero with a cross-party group of MPPs. This was the first of a series of APPG roundtable discussion on net zero, being spearheaded by Dr Tim Kruger as part of the Net-Zero Network programme : http://www.netzero.org.uk/

There is growing global consensus on the importance of addressing climate change and biodiversity loss together. Promoting policy coherence, and broader alignment with sustainable development goals necessitates active collaboration across sectors. Recognizing the importance of this, the European Commission (DG ENV Biodiversity Unit) convened a 2-day workshop to stimulate knowledge exchange between approximately 70 partners across government, civil society organizations, and the private sector on the potential of Nature-based Solutions (NbS). Embodying the interlinked nature of biodiversity and climate change by design, NbS can be powerful tools to address both challenges if implemented at scale.

Embodying the interlinked nature of biodiversity and climate change by design, NbS can be powerful tools to address both challenges if implemented at scale

A key objective was to stimulate awareness and understanding around how NbS can promote synergy between biodiversity, climate and sustainable development policies at the international and EU level. Policy coherence is a corner stone of an effective enabling environment to support the scaling up of NbS. Coined ‘the biodiversity super year’ several key events are shaping up this year to inform climate and biodiversity policy, including the CBD (Convention on Biodiversity) CoP 15 and the UNFCCC CoP 26. In particular, the focus is on the post 2020 global biodiversity framework (to be released in October following the CBD CoP in Kunming, China), and the European Green Deal. The European Green Deal holds the potential to provide an integrated framework for EU-level initiatives, including the biodiversity strategy, climate law, zero pollution, and circular economies to support the restoration of Europe’s nature, address climate change, and improve human well-being.

The workshop highlighted how NbS can be successfully scaled-out across vast landscapes. For example, we heard from Elvis Paul Tangram on the Sahel Great Green Wall Initiative, and Lea Appulo (Wetland International; Asian & European Wetlands) who spoke of their experience in taking NbS to scale in the Sahel and Indonesia to increase resilience to the impacts of climate change. Patrick Worms highlighted how regenerative, nature-based modes of farming hold tremendous potential for taking NbS to scale and generate more sustainable farming systems. Great strides can be achieved through innovation in the private sector as well. For example, a representative from Danone who attended the workshop highlighted how Danone is working on a regenerative farming model to promote agricultural resilience and promote soil carbon sequestration. However, bringing NbS to scale entails important challenges.

Taking NbS to scale requires socioeconomic transformation

Joseph Settele (co-chair of IPBES Global Assessment and IPCC CLO) set the backdrop by summarizing the recent IPBES global biodiversity and ecosystems services assessment report. Economic growth over the past 50 years has led to a 4-fold increase in the size of the global economy, a 10-fold increase in global trade, and the spatial segregation of production and consumption. This has coincided with marked declines in the majority of ecosystem services, posing significant risks to human well-being and our capacity to address climate change. For example, Lea Appulo (Wetlands International) highlighted that we’ve lost 85% of wetlands globally, at a rate 3x faster than forests. Similarly, The WEF Global Risk Report for 2020 showed that the top 5 risks to the global economy are associated with biodiversity loss climate change. Joseph highlighted that under business as usual economics, internationally agreed goals and targets for biodiversity will continue to be missed, leading to severe and unequally distributed consequences. For example, dominant legal frameworks, including across Europe incentivize economic activities which damage rather than support nature. Addressing this requires a concerted set of actions across scales to reform governance, economic systems, equity, promote cross-sectoral planning, and support social narratives that question the economic growth imperative and raise ambition for nature.

Public money is essential to support a transition towards NbS across sectors

Ultimately public money is a crucial factor to kick start the transition, as businesses and farmers are unlikely to take the initial risks of shifting modes of production at scale, which in the short-term can impose heavy cost burdens. However, businesses do bear a share of the responsibility in facilitating this transition, and large businesses, like Danone, that are dependent on resilient production landscapes can assert significant leverage to reform supply changes.

Successfully scaling up NbS does not require ‘a one-size fits all’ approach

There is a tension between the need to scale-out NbS across landscapes, and the context-specific nature of successful NbS implementation. To be successful, NbS need to be shaped to local social-ecological realities. However, large scale NbS initiatives, such as the Great Green Wall Initiative, can be successful so long as they provide a framework which allows shaping practices to local realities. This is crucial, highlighted Graham Wynne, because while adaptation is often framed as being context specific it often works best at scale, such as for managed retreat in costal zones to address sea level rise and associated impacts, or large-scale restoration to protect watersheds. Successfully navigating this tension is therefore key to maximize impact at scale.

Successful NbS are co-created with the engagement of local stakeholders

Patrick Worms (President European Agroforestry Federation) emphasized that NbS cannot be designed in ivory towers. Approaches conceptualized in academic silos are disconnected from local realities and often fail as a result. The successful implementation of NbS rests on engaging local stakeholders from the start. Such approaches are termed transdisciplinary, as they involve the merging of knowledge and expertise across sectors. Academics and NGOs can help harness science to support the design of NbS, and in turn, local stakeholders bring the in-depth understanding of local social and ecological realities crucial to inform the design of NbS. Patrick Worms highlighted how, in the 1980s, new alley cropping methods conceptualized by academics failed on the ground because they were incompatible with local farmers’ ways of working. Therefore, the appreciation and weaving of diverse ways of knowing is not only an ethical imperative, but essential from a practical point of view. Afterall, the keystone species in any nature-based system is humans, and therefore their engagement is crucial to the success of NbS.

Collaboration is key to success

Only through collaboration will a global movement emerge, underpinned by strategic vision to support the scaling up of existing initiatives and projects. David Nabarro (NbS Coalition facilitator, 4SD) underlined that advancing NbS requires focusing on the ‘4 Ps’ – Processes, People, Politics, and Practices. He emphasized the need for collaborations through multi-stakeholder, multi-disciplinary platforms across various groups working on biodiversity, agriculture, climate and development to combat sectoralized government decision making. He highlighted that an integrated approach is not only necessary to achieve the SDGs, but politically desirable.

Powerful narratives are crucial to scale up NbS

David explained how changing the narrative from ‘nature or people’ to ‘nature and people’ has created unprecedented political momentum for NbS. We need powerful narratives and champions across sectors to mainstream them. While economic valuation can be key to increase the engagement of key stakeholders such as farmers and businesses, alone it is not enough. Ultimately, promoting collaboration and increasing ambition for NbS across sectors and decision-making scales requires re-shifting priorities to recognize the benefit of harmonious interactions between people and nature. A challenge however is clarifying what this narrative means in practice, as it is subject to conflicting stakeholder views, for example between farmers and ecologists. David Nabarro and Stewart Maginnis (Global Director of Nature-based Solutions Group) suggested that mainstreaming nature in political processes and successfully navigating the complexities such work entails will require reducing adversarial tendencies by engaging in dialogue with unlikely allies.

Getting the messaging right is key to promote an understanding of NbS and generate demand

A key theme of the workshop was around getting the messaging right about NbS. While the term NbS is relatable and salient to many, we need to get the story right and promote stories that help to create understanding of and demand for NbS among a wide range of actors. To do so we need to attach easy-to-grasp messages to the concept, whilst not underestimating complexity. While simplicity in messages is often sought for policymaking, oversimplifying NbS can displace the nuances which need to be appreciated to implement effective, place-based approaches. The key is striking the right balance between simplicity and complexity for a particular decision-making context, as highlighted by Graham Wynne. While challenging, honest but effective communication is essential for uptake of the concept and to harness its potential for societal change.

NbS should support or enhance biodiversity, but not all conservation measures are NbS

As said by Stewart Maginnis, this requires acknowledging that while all NbS should support and enhance biodiversity, not all conservation measures can be classified as NbS. This is because NbS and conservation approaches diverge in their ultimate outcomes. While NbS focuses on ecosystem health, and landscape integrity, ultimately the focus is on addressing societal challenges for people, while conservation focuses on the preservation of species and ecosystems. Therefore, a given NbS may not necessarily be the best action for benefitting biodiversity. For example, on degraded landscapes, the best action from a conservation standpoint may be to fully restore intact forests, whereas from an NbS standpoint, the solution to best address local needs may be a mosaic of forest restoration and agroforestry. Graham Wynne highlighted that ensuring honest narratives around NbS is essential because such potential trade-offs need to be appreciated for informed decision-making.

What counts as a NbS should be defined within the boundaries of a given social-ecological context

Differentiating what is and is not a NbS from an objective standpoint is implausible because the answer is context dependent. Meaningful discussions of what counts as a NbS should be framed around a defined social-ecological context. The spatial, temporal, and stakeholder boundaries of the system need to be explicitly delineated in practice. In turn, what qualifies as a NbS in one setting may not qualify as a NbS elsewhere. First, what determines a NbS depends on for whom and for what the approach is conceptualized. A NbS to a specific issue depends on the perspectives of local stakeholders (e.g. i.e. what issue to address). Second, what is counts as a NbS depends on the counterfactual i.e. what would have happened otherwise. For example, agroforestry may not be a NbS if it entails replacing primary forest which sustains water production for the local community. However, the same action may be framed as a NbS if it replaces unsustainable intensive modes of agricultural production, or is established on degraded grazing land.

Context-specificity does not preclude the design of NbS guidelines

The context-specificity of NbS does not render core messages or guidance around NbS impossible. To the contrary, we need to be clear on the value proposition of NbS. Guidance is essential to shape effective narratives and support evidence-base policy and practice. The key is to promote flexible guidelines which can be applicable across contexts. For example, David Nabarro highlighted that NbS should not be viewed as an offset mechanism, which many see as a serious barrier to reducing emissions. Recently published guidelines by the NbSI highlight this point, along with three other core messages for sustainable, successful NbS. Stewart Maginnis discussed the Global Standards for NbS to be launched at the World Conservation Congress in June 2020 after a multi-phase global stakeholder consultation process. These are designed to operationalize a set of core principles for NbS. The point was made that these standards are meant to be facilitative rather than normative, in order to support rather than define or standardize the design, implementation, monitoring and evaluation of NbS. In line with the view of NbS as approaches to global challenges, these standards are designed to be broadly applicable. Therefore, they do not specifically focus on NbS to address climate change, but on NbS to benefit society in any way.

Concluding notes

Nature-based Solutions hold great potential to address global environmental crises and support sustainable development and well-being. Harnessing NbS to support a transformation towards a socially and environmentally sustainable world requires powerful narratives. Together, we can collaborate to generate success stories and evidence to support greater appreciation of and demand for NbS. As key processes and events in biodiversity and climate policy proceed, this year presents a crucial opportunity to mainstream NbS. The NbSI is committed to supporting evidence-based policy on NbS and a broader understanding of how NbS can be harnessed for climate change.

Alex Chausson

Trees have been shown to cause significant cooling in Madison, Wisconsin. Trees have a cooling effect due to reflecting more sunlight than darker surfaces, and the latent heat of  evaporation from leaves. The study showed that daytime air temperature decreased with increasing canopy cover; for example, increasing canopy cover from 0-100% corresponded with a decrease in temperature by 1.3°C within a 30m radius. The effect was nonlinear, with canopy cover of over 40% leading to substantially cooler temperatures.

Impervious surfaces such as asphalt opposed the cooling effect of trees, with air temperature increasing linearly with greater impervious cover. The warming effect of impervious surfaces cannot be completely counteracted by tree cover, because canopy cover has a limited effect on heat at night (in part due to reduced photosynthesis and consequent evaporation). Therefore reduction of impervious cover is also needed to reduce urban heat.

The use of nature-based solutions for cooling in cities will become increasingly important as climate change progresses, due to acceleration of the urban heat island effect (cities are commonly 5-15°C warmer than surrounding areas).

Use of vegetation in urban areas in the Mid-Atlantic watersheds of Washington DC, Montgomery County and Baltimore County MD, has reduced flooding and nutrient runoff. The ‘stormwater green infrastructure’ in these municipalities includes green roofs, bioswales, rain gardens and stormwater ponds. By increasing infiltration and groundwater recharge, and/or evaporation, they reduce the volume of run-off that can contribute to floods. A study found that the watersheds with more stormwater green infrastructure had less ‘flashy’ hydrology, with peak runoff being 44% lower (mm/day), and runoff events being 26% less frequent and 26% less variable. Taken together this suggests that the green infrastructure reduced the potential for flooding. Of the areas studied, DC had the greatest proportion of its landscape drained through green infrastructure, at 12.7%, whilst Baltimore County had the lowest, at 7.9%. Furthermore, the green infrastructure was shown to decrease nitrate export by 44%, hence likely decreasing nutrient pollution of rivers and consequent harm to wildlife.

The green infrastructure was found to have not caused a significant reduction in phosphorous exports or sewer overflows. This was likely because the scale of implementation was too small. Indeed, to reduce flooding during heavy rainfall (like that predicted with climate change), the area of stormwater green infrastructure would need to be significantly larger. In order to maximise the benefit from increasing green infrastructure area, further investigation is needed into the differential effects of the various types of stormwater green infrastructure and the impact of their location.

Balarus is leading the way for peat restoration in Europe. Peatlands cover about 23% of the country, but most of it is degraded or drained. The country’s peatlands have long been seen primarily as a resource for agriculture and energy, but since the 1990s efforts have been made to protect, restore, and sustainably use the habitat. It’s estimated that over the past decade 50,000 ha of degraded peatlands have been rewetted, and the government scheme aims to allocate 29% of total peatland area to conservation by 2030 (almost all the remaining natural peatland). Peatland restoration provides a number of benefits: carbon sequestration, water quality improvement and biodiversity conservation, and can be done alongside sustainable use (e.g. biomass production for fuel in a process called paludiculture).

Drained and mined peatlands are vulnerable to burning, which releases ancient carbon from dead organic matter. Climate change-induced drought will cause peatlands to become drier, making burning more likely. Hence rewetting of drained peatland, and restoration of mined peatland, is important for reducing the risk of release of large quantities of carbon.

Peatland restoration is also central to biodiversity conservation in Belarus. For example, the aquatic warbler declined by 40% in 10 years due to drainage of its habitat. Belarus is home to about 40% of the global breeding population of this species, so restoration of peatland is hoped to give the species a boost.

The township of Humbo in Ethiopia had lost most of its surrounding forests by the late 1960s, but a recent initiative is turning this around. 2700 hectares of degraded native forest have been restored since 2006 through a community-based project. The forest was regenerated using a method called farmer-managed natural regeneration (FMNR) involving pruning, management and protection of stems growing from stumps, roots and seeds. This low-cost method rapidly provides direct benefits for local people: fodder and firewood is harvestable within a year and wild fruit and other forest products within three years. There are also indirect benefits in the form of reduced water runoff preventing flooding, and reduced erosion improving water quality. The participating farmers also receive payments for enhancing carbon storage. In this way, the project ameliorates poverty, provides sustainable sources of food and income, and increases biodiversity. Read about more FMNR examples in action.

The re-conversion of winter cereal fields into grassland contributed to the cessation of winter floods in a downstream housing estate in the South Downs of England. In the mid-1980s grassland in the catchment was converted into cereal crops, resulting in the soil holding less water and reducing the amount of rain required for flooding and erosion to take place: one-in-100-year flooding events started to happen every three or four years, resulting in flooding of the housing estate in the winters of 1990/91 and 1993/94. The major action to combat the floods was the conversion of some fields back into grassland, together with construction of small dams, putting tramlines into crops, and working fields along the slope rather than across the valley floor. After these interventions, even during very heavy rainfall that caused flooding in nearby places, the housing estate was subjected to no flooding.

Mangrove forests in eastern India were shown to protect villages and crops from flooding during a cyclone with 260km/hr winds and a 9m storm surge. The mangroves had been protected from deforestation and overexploitation since 1985. A comparison of inundation and damage between villages found that those further away from mangroves suffered more extensive damage than those in the mangrove shadow. The village that was not protected by mangroves, but was separated from the sea by an artificial embankment, experienced a lower level of farmland inundation compared to the village without mangroves or an embankment. This was due to the embankment trapping water, resulting in more crop-damage than the village without either form of protection. Overall, in this case the mangroves provided better protection from the cyclone than the artificial defence, which performed worse than no protection at all.

The same study showed that the majority of local people perceived benefits from the mangroves. Those living in the immediate vicinity of the coastal forests valued the additional nutrients they provided most highly, whilst those living further away saw flood protection as the main benefit. Furthermore, 93% of those interviewed were in favour of the integrated conservation and development programme, and 43% said they were willing to cooperate with the forest department for mangrove restoration. However, 18% said they felt that their rights were violated by the protected area, largely due to reduced access to firewood.

There are a number of additional benefits of protecting and restoring intact mangrove forests: breeding, feeding and nursery grounds for fish, sources of fodder, timber, and medicinal plants, erosion reduction, and eco-tourism. However, mangrove restoration globally has been implemented with limited success. For example, one study found that of 1000-1200ha of mangroves that have been under restoration in Sri Lanka, only 200-220ha (~19%) were successful. The poor success of many projects is primarily attributed to planting of inappropriate species in unsuitable places and poor land tenure arrangements. Our understanding of how things went wrong can be used to inform successful restoration projects.

Many community forest projects have been set up in Nepal. A study of 105 of these found that they have been broadly successful for both increasing carbon sequestration and providing social benefits. The projects have been strengthened as part of the United Nations Reduced Emissions through Deforestation and forest Degradation (REDD+), which provides incentives for increasing carbon stocks in forests. This involved encouraging reduced extraction of forest resources, such as by providing cooking stoves and biogas plants to reduce the need for firewood collection, raising awareness about sustainable harvesting (e.g. of fodder for livestock and fruits/roots to feed families), guarding to control illegal harvesting, and creating alternative sources of income. The latter involved, for example, provision of goats and buffalo to disadvantaged members of communities. In addition, creation of plantations on uncultivated land or sparse forest was encouraged.

Overall the REDD+ activities were found to provide both climate mitigation and adaptation benefits. Carbon stocks increased by an average of 5.1 MgC/ha/yr between 2010 and 2013, with the greatest increase in dense pine forests. However, in some plots’ carbon stocks markedly decreased, largely due to illegal harvesting, logging and road building. The REDD+ project was confirmed to provide social benefits, through increasing communication and cooperation between communities and organisations. Interviews showed that this resulted in increased confidence in the resilience of the communities to climate change.