Continuing to produce nature-based credits using dubious accounting methodologies will yield limited carbon and biodiversity gains. Establishing scientific credibility unlocks the potential of credits to meaningfully contribute to targets of the Paris and Kunming-Montreal agreements.
Archives: Publications
Established in 2002, the Amazon Protected Areas Program (ARPA) supports 120 Conservation Units (CUs) in the Brazilian Amazon, covering 62 Mha. Here, we quantified the impact of ARPA support on reducing deforestation and CO2 emissions between 2008 and 2020. We started by examining critical methodological choices, often brushed over in the impact evaluation studies on protected areas (PAs). We then applied a covariate balancing method to control for variation in covariates so as to compare differences in deforestation between Strictly Protected (SP) and Sustainable Use (SU) CUs with and without ARPA support as well as to assess the influence of ARPA investment mechanism on the differential reductions. Next, we estimated total reductions in deforestation and CO2 emissions by using the Adjusted Odds Ratio. We found that ARPA support accounts for additional deforestation reductions of 9 % in SP CUs and 39 % in SU CUs in relation to non-supported CUs. The effects of ARPA investment mechanism were statistically significant for both categories of CUs. CUs plus Indigenous Lands (i.e., PAs) reduced by 21 % (2.0 ± 0.3 Mha) Amazon deforestation between 2008 and 2020. Of this total, ARPA CUs accounts for 264 ± 25 thousand ha, the equivalent of 104 ± 10 Mtons of CO2 emissions. If deforestation continues unabated, PAs will become the last citadels of the Amazon. However, protecting the Amazon only with PAs does not suffice. Additional investments in a comprehensive conservation policy mix are needed along with a monitoring and evaluation strategy to provide evidence on what works for effective and socially equitable forest conservation.
Forest regeneration is a crucial strategy for mitigating and adapting to global warming. Yet its precise impact on local climate remains uncertain, a factor that complicates decision-making when it comes to prioritizing investments. Here, we developed global maps illustrating how natural forest regeneration influences key local climate drivers—land surface temperature (LST), albedo, and evapotranspiration—using models fitted at a 1-km spatial resolution with a random forest classifier. We found that natural forest regeneration can alter annual mean LST by 0.01 °C, −0.59 °C, −0.50 °C, and −2.03 °C in Boreal, Mediterranean, Temperate, and Tropical regions, respectively. These variations underscore the region-specific effects of forest regeneration. Importantly, natural forest regeneration reduces LST across 64% of 1 billion hectares and 75% of 148 million hectares of potentially restorable land under different scenarios. These findings improve understanding of how forest regeneration can help regulate local climate, supporting climate adaptation efforts.
Extensive forest restoration is a key strategy to meet nature-based sustainable development goals and provide multiple social and environmental benefits1. Yet achieving forest restoration at scale requires cost-effective methods2. Tree planting in degraded landscapes is a popular but costly forest restoration method that often results in less biodiverse forests when compared to natural regeneration techniques under similar conditions3. Here we assess the current spatial distribution of pantropical natural forest (from 2000 to 2016) and use this to present a model of the potential for natural regeneration across tropical forested countries and biomes at a spatial resolution of 30 m. We estimate that an area of 215 million hectares—an area greater than the entire country of Mexico—has potential for natural forest regeneration, representing an above-ground carbon sequestration potential of 23.4 Gt C (range, 21.1–25.7 Gt) over 30 years. Five countries (Brazil, Indonesia, China, Mexico and Colombia) account for 52% of this estimated potential, showcasing the need for targeting restoration initiatives that leverage natural regeneration potential. Our results facilitate broader equitable decision-making processes that capitalize on the widespread opportunity for natural regeneration to help achieve national and global environmental agendas.
Achieving net-zero climate targets requires some level of carbon dioxide removal. Current assessments focus on tonnes of CO2 removed, without specifying what form these removals will take. Here, we show that countries’ climate pledges require approximately 1 (0.9–1.1) billion ha of land for removals. For over 40% of this area, the pledges envisage the conversion of existing land uses to forests, while the remaining area restores existing ecosystems and land uses. We analyse how this demand for land is distributed geographically and over time. The results are concerning, both in terms of the aggregate area of land, but also the rate and extent of land use change. Our findings demonstrate a gap between governments’ expected reliance on land and the role that land can realistically play in climate mitigation. This adds another layer to the observed shortcomings of national climate pledges and indicates a need for more transparency around the role of land in national climate mitigation plans.
Biodiversity metrics are increasingly in demand for informing government, business, and civil society decisions. However, it is not always clear to end users how these metrics differ or for what purpose they are best suited. We seek to answer these questions using a database of 573 biodiversity-related metrics, indicators, indices, and layers, which address aspects of genetic diversity, species, and ecosystems. We provide examples of indicators and their uses within the state–pressure–response–benefits framework that is widely used in conservation science. Considering complementarity across this framework, we recommend a small number of metrics considered most pertinent for use in decision-making by governments and businesses. We conclude by highlighting five future directions: increasing the importance of national metrics, ensuring wider uptake of business metrics, agreeing on a minimum set of metrics for government and business use, automating metric calculation through use of technology, and generating sustainable funding for metric production.
Natural climate solutions (NCS) play a critical role in climate change mitigation. NCS can generate win–win co-benefits for biodiversity and human well-being, but they can also involve trade-offs (co-impacts). However, the massive evidence base on NCS co-benefits and possible trade-offs is poorly understood. We employ large language models to assess over 2 million published journal articles, primarily written in English, finding 257,266 relevant studies on NCS co-impacts. Using machine learning methods to extract data (for example, study location, species and other key variables), we create a global evidence map on NCS co-impacts. We find that global evidence on NCS co-impacts has grown approximately tenfold in three decades, and some of the most abundant evidence relates to NCS that have lower mitigation potential. Studies often examine multiple NCS, indicating some natural complementarities. Finally, we identify countries with high carbon mitigation potential but a relatively weak body of evidence on NCS co-impacts. Through effective methods and systematic and representative data on NCS co-impacts, we provide timely insights to inform NCS-related research and action globally.
Multi-functional urban green infrastructure (GI) can deliver nature-based solutions that help address climate change, while providing wider benefits for human health and biodiversity. However, this will only be achieved effectively, sustainably and equitably if GI is carefully planned, implemented and maintained to a high standard, in partnership with stakeholders. This paper draws on original research into the design of a menu of GI standards for England, commissioned by Natural England—a United Kingdom Government agency. It describes the evolution of the standards within the context of United Kingdom government policy initiatives for nature and climate. We show how existing standards and guidelines were curated into a comprehensive framework consisting of a Core Menu and five Headline Standards. This moved beyond simplistic metrics such as total green space, to deliver GI that meets five key ‘descriptive principles’: accessible, connected, locally distinctive, multi-functional and varied, and thus delivers 5 ‘benefits principles’: places that are nature rich and beautiful, active and healthy, thriving and prosperous, resilient and climate positive, and with improved water management. It also builds in process guidance, bringing together stakeholders to co-ordinate GI development strategically across different sectors. Drawing on stakeholder feedback, we evaluate the strengths and weaknesses of the standards and discuss how they provide clarity and consistency while balancing tensions between top-down targets and the need for flexibility to meet local needs. A crucial factor is the delivery of the standards within a framework of supporting tools, advice and guidance, to help planners with limited resources deliver more effective and robust green infrastructure with multiple benefits.
Social contracts are evolving relationships between the government and the public; they describe the rights and responsibilities of each party in catastrophic hydroclimatic events. As the climate crisis unfolds disaster losses continue to increase and the need for new infrastructure is becoming more apparent. Research suggests that incorporating Nature-based Solutions (NbS) into infrastructure adaptations may reduce exposure and loss and improve social well-being. While researchers and policy makers push for NbS, it is unclear whether they adequately recognize contemporary social contracts and whether these contracts are shifting sufficiently to accept the differences. We operationalize social contracts and test a conceptual approach through analysis of tweets before, during and after Hurricane Ida. Our results indicate a social contract of inequalities manifested through experience, perceptions and expectations of citizens. There is a great deal of uncertainty and feelings of insecurity about the public’s perception of government response and resource provisions. Although our results indicated a gap in public perception of NbS, uncertainty about the effectiveness of conventional infrastructure was expressed. Public expectations include an evolving social contract that addresses the challenges related to inequalities while also adapting to climate change. We discuss how this twitter data can be used to understand the role of social contracts in responding to disaster risk and infrastructure adaptation and how inadequacies in current protection measures can inform potential use of NbS.
The creation of wetlands along river channels, or inter-levee floodplain wetlands (ILWs), increases the cross-sectional area of rivers for flood control and is an effective nature-based solution (NbS) that is expected to achieve both flood control and biodiversity conservation in floodplains in riverine areas in Japan. To clarify the differences in habitat functions between ILWs and rice paddy fields, we surveyed the species assemblage and habitat usage of aquatic animal assemblages in ILWs and nearby rice paddies in the Nobi Plain of central Japan. Rana japonica bred in the ILWs, and taxon numbers of Odonata larvae and aquatic Hemiptera were greater in ILWs than in rice paddies. Fish taxa were also more abundant in the ILWs. ILWs were characterized mainly by taxa with a preference for permanent water bodies in their life history, whereas Dryophytes japonicus, Pelophylax porosus brevipodus, and Fejervarya kawamurai inhabited and bred mainly in the rice paddies, and the number of taxa of aquatic Coleoptera was also higher. The assemblages in the rice paddies were characterized by pioneer taxa with a preference for temporary waters as their primary breeding sites. Our results show that the creation of ILWs for flood control and the maintenance of rice paddies could help to conserve the original floodplain biodiversity through the complementarity of these different wetland types.
Coastal flood risk poses a serious, existential threat to shoreline populations around the world both now and in the future. Unsurprisingly, global decision makers are considering their options – one of these being Nature-based Solutions – for effective disaster risk reduction which specifically targets coastal flooding. While strides have been made in the field of Nature-based Solutions for coastal flooding, much of this attention has been directed towards the urban setting, with a wealth of scholastic documentation to support this notion. The sizeable rural populations scattered throughout the world’s small coastal communities, meanwhile, have been largely neglected in academic literature. Without this information, it is impossible to properly capture the full potential of Nature-based Solutions in (global) flood risk modelling endeavours or understand their role in the future of equitable disaster risk reduction. In light of this gap, we have reviewed the limited amount of existing literature from around the world involving the implementation and effectiveness of Nature-based Solutions in small coastal communities. We analysed 28 peer-reviewed studies to gather common themes and insights about the barriers and opportunities unique to these rural shorelines. Takeaways we have identified include a near consistent scarcity of resources (e.g., technical, financial, institutional) to implement disaster risk reduction measures; an abundance of space and opportune land use regimes which make Nature-based Solutions a highly plausible option; amplified nature contributions to people leading to larger benefits reaped from investments into Nature-based Solutions; and the presence of local knowledge regarding societal norms, climate patterns, and ecosystem capabilities. We argue that these four common themes point to the fact that more attention must be given to coastal flooding-focused Nature-based Solutions in the rural setting. As such, we present this collation as a starting point for future projects of similar setting and scope. We also recommend improving benefit-cost analysis methods as well as including local knowledge and other perspectives in future global assessments of coastal flood risk.
Effective disaster risk reduction measures are vital to coastal communities around the world. While nature-based solutions provide coastal communities with a promising alternative to traditional engineering-based solutions; these solutions are often overlooked by communities when planning and implementing disaster risk reduction measures. This study builds upon the literature that demonstrates the effectiveness of coral reef conservation to mitigate coastal flood risk. Our approach utilizes freely available tools and data to quantify the economic value of coral reef conservation for the Hawaiian Islands. We explore a scenario that depicts coastal flooding if the upper 1 m of the coral reef were to be lost. The study analyzes the Average Annual Loss (AAL) and losses avoided based on a series of 4 coastal flood scenario return periods with and without coral reefs. This case study finds that the preservation of the upper 1 m of coral reefs for the main islands of Hawaiʻi provides the state with $629 million in annual losses avoided to buildings. A hot spot analysis of the losses avoided identifies areas where conservation efforts could be prioritized. Our findings provide additional support to the use of nature-based solutions as an effective disaster risk reduction measure, and provides communities and stakeholders with a methodology that can be implemented using readily available data and tools.
The use of nature-based solutions (NbS) to address the risks posed by hydro-meteorological hazards have not yet become part of the mainstream policy response, and one of the main reasons cited for this, is the lack of evidence that they can effectively reduce disaster risk. This paper addresses this issue, by providing model-based evidence from five European case studies which demonstrate the effectiveness of five different NbS in reducing the magnitude of the hazard and thus risk, in present-day and possible future climates. In OAL-Austria, the hazard is a deep-seated landslide, and the NbS analysed is afforestation. Modelling results show that in today’s climate and a landcover scenario of mature forest, a reduction in landslide velocity of 27.6 % could be achieved. In OAL-Germany, the hazard is river flooding and the NbS analysed is managed grazing with removal of woody vegetation. Modelling results show that the NbS could potentially reduce maximum flood water depth in the near-future (2031–2060) and far-future (2070–2099), by 0.036 m and 0.155 m, respectively. In OAL-Greece, the hazard is river flooding, and the NbS is upscaled natural storage reservoirs. Modelling results show that in a possible future climate the upscaled NbS show most potential in reducing the total flooded area by up to 1.26 km2. In OAL-Ireland, the hazard is surface and river flooding, and the NbS is green roofs. Results from a modelled upscaling analysis under two different climate scenarios show that both maximum flood water depth, and total flooded area were able to be reduced. In OAL-UK, the hazard is shallow landslides, and the NbS is high-density planting of two different tree species. Modelling results under two different climate scenarios show that both tree species were able to improve slope stability, and that this increased over time as the NbS matured. The significance of these results is discussed within the context of the performance of the NbS over time, to different magnitude events, impact with stakeholders in engendering wider support for the adoption of the NbS in the OALs, and the uncertainty in the modelling analyses.
Tropical America is a biogeographically megadiverse region, hosting 4 of the 36 global biodiversity hotspots: Tropical Andes, Tumbes-Choco Magdalena, Mesoamerica and the Caribbean islands ; 6 of its 17 countries are considered megadiverse. Such megadiversity is a result of a complex geography which also contributes to the region’s exposure to extreme events and high vulnerability to climate change. In these settings, natural capital1 could be the engine for innovative development and, if better understood, used to increase resilience and adaptation to global environmental change, including potential changes in the magnitude and frequency of extreme events
Nature-based solutions (NbS) have received increased interest as cost-effective contributors to addressing societal challenges, with ecosystem-based disaster risk reduction (Eco-DRR) being the specific approach for reducing disaster risk under the NbS umbrella. Ecosystem services (ES) provided by Eco-DRR measures are known to contribute to reducing all three components of disaster risk. Yet, Eco-DRR evaluation falls short of recognising this, and this hampers its strategic placement and effective use. This paper addresses the challenge of evaluating the impact of Eco-DRR measures on reducing hazard, exposure and vulnerability. The methodological approach for Eco-DRR evaluation is developed for agroforestry as an example of ecosystem-based measure for flood risk reduction. The literature review on ES provided by cropland versus agroforestry provided the basis to elaborate on how the quantitative evaluation of such a measure for flood risk reduction could be realised in a next step. An additional literature review served to create a look-up table on the effects of agroforestry on hydrological processes in comparison to cropland. This can serve as input for re-running the hydrological model and comparing the hazard before and after the agroforestry implementation. The paper also captures the effects of agroforestry implementation on social and ecological vulnerability through changes in ES provision. Changes in ES provision resulting from the implementation of an agroforestry measure on cropland were related to social and ecological vulnerability using a deductive approach. The concept for comprehensive evaluation developed in this paper provides the groundwork for evaluating the risk reduction potential of Eco-DRR with reference to a tailored risk assessment.
Nature-based solutions (NbS) have received increased interest as cost-effective contributors to addressing societal challenges, with ecosystem-based disaster risk reduction (Eco-DRR) being the specific approach for reducing disaster risk under the NbS umbrella. Ecosystem services (ES) provided by Eco-DRR measures are known to contribute to reducing all three components of disaster risk. Yet, Eco-DRR evaluation falls short of recognising this, and this hampers its strategic placement and effective use. This paper addresses the challenge of evaluating the impact of Eco-DRR measures on reducing hazard, exposure and vulnerability. The methodological approach for Eco-DRR evaluation is developed for agroforestry as an example of ecosystem-based measure for flood risk reduction. The literature review on ES provided by cropland versus agroforestry provided the basis to elaborate on how the quantitative evaluation of such a measure for flood risk reduction could be realised in a next step. An additional literature review served to create a look-up table on the effects of agroforestry on hydrological processes in comparison to cropland. This can serve as input for re-running the hydrological model and comparing the hazard before and after the agroforestry implementation. The paper also captures the effects of agroforestry implementation on social and ecological vulnerability through changes in ES provision. Changes in ES provision resulting from the implementation of an agroforestry measure on cropland were related to social and ecological vulnerability using a deductive approach. The concept for comprehensive evaluation developed in this paper provides the groundwork for evaluating the risk reduction potential of Eco-DRR with reference to a tailored risk assessment.
Emergent complex climate risks challenge conventional approaches for climate adaptation (CCA) and disaster risk reduction (DRR). This situation demands new ways of addressing climate risks with integrated solutions. Nature-based Solutions (NbS) are promising CCA and DRR given their cost-effectiveness, multifunctionality and low-regret condition in addressing a wide range of risks exacerbated by climate change. However, little attention has been paid to exploring methodological approaches for combining NbS to reduce climate risks. Still, selecting the appropriate and effective combination of NbS is a challenging task. This research applies a geospatial multi-criteria approach for developing intervention packages of NbS for CCA and DRR and applies this innovative methodology to a case study area in the Puna region in Peru. The study started with an in-depth literature analysis coupled with a participatory process with local experts to identify and select locally valid NbS for CCA and DRR. Building upon that, the overall multi-criteria approach was developed, which consists of a matrix-based procedure to evaluate the applicability of relevant measures and their feasibility of being combined in intervention packages. Then, the multi-criteria analysis was integrated into a Geographic Information System using a spatial analysis model to map suitable intervention areas. Next to the methodological innovation, the multi-criteria approach was applied to a case study area to generate a place-based intervention package for addressing the risk of reduced water provision considering climate change conditions, with its respective potential intervention sites differentiated by the appropriate measures. This methodological approach is a novel and pragmatic support tool that helps practitioners design more robust and effective interventions for building resilience to climate change. Furthermore, this methodological approach involves shifting the perspective from activities focused on “one-size-fits-all-solution” to “multi-solution” strategic interventions that address climate risks more comprehensively, recognizing the dynamics and complexities of the social-ecological systems. The authors encourage researchers and practitioners to transfer the methodological approach to other contexts and, with that, accelerate the efficient and targeted implementation of NbS for building resilience to climate change.
Disaster risk reduction (DRR) is one of the most important societal challenges addressed under the umbrella term nature-based solutions (NbS). One NbS approach that specifically addresses risk reduction is ecosystem-based disaster risk reduction (Eco-DRR). However, there are other approaches, such as integrated fire management or protective forests, which directly aim at reducing the risk of specific natural hazards. Other approaches, such as ecosystem-based adaptation (EbA), do not have DRR as a primary goal, but contribute to it in the form of synergies and co-benefits. Based on a comprehensive literature search of the Scopus database covering all articles published in English during the period 2000–2021, we analyze existing NbS approaches and those which address DRR. In a further step, we select all original research articles (n = 114) that refer to NbS for DRR projects or interventions conducted in a specific geographic area and analyze them in terms of (1) approach applied; (2) natural hazards mitigated; (3) ecosystem services for DRR provided; (4) geographic and biophysical site conditions, and (5) measures and techniques used. The analysis forms the basis for developing a typology of NbS for DRR, which we present for discussion. This typology helps scientists, policymakers, planners, and other stakeholders to gain a systematic overview of the NbS for DRR approaches currently addressed in the literature and to advance systematization of these approaches.
This study performs an economic efficiency and equity analysis of four recent Ecosystem-based Disaster Risk Reduction (Eco-DRR) interventions in Haiti, India, Indonesia, and Uganda. Our analysis aims at contributing to the development of methodological best practices for assessing both the economic-effectiveness and the distributional impacts of nature-based solutions, with a particular focus on marginalized or underserved communities. Nature-based solutions (NbS) are emerging as possible strategies to mitigate disaster risk while providing additional benefits to biodiversity and sustainable economic growth. However, there is limited scientific evidence about the cost-effectiveness and equity outcomes of NbS. For each ecosystem-based intervention examined we performed an economic efficiency assessment through a quantitative cost-benefit analysis (CBA). Our estimates show that at the 5th year since the project implementation, the interventions in Haiti and India generated positive net benefits, assuming hazard-related yearly losses in properties and GDP per capita in the project areas as low as 0.5 %. We observe the same outcomes in Indonesia and Uganda at the 10th year since the project implementation, assuming yearly losses equivalent to 1 % or higher and adopting a 3 % discount rate. When we include additional benefits from carbon capture and sequestration and pollution reduction the CBA net benefits estimates are positive at the 10th year mark for every discount rate adopted. Extensive qualitative interviews of local stakeholders corroborate the CBA results and provide insights on the numerous additional benefits experienced, which in the future could be measured and monetized if monitored over time. A qualitative analysis of the distributional effects of the interventions was performed to complement the economic efficiency assessment. This equity analysis indicates an enhancement in inclusivity, economic equality, participation, and capacity building among local stakeholders. In particular, the Eco-DRR interventions implemented resulted in significant education, health, safety and economic improvements for women, children, and economically vulnerable members of the local communities.
In natural grasslands under extensive grazing, volcanic events pose risks to livestock health and production. Volcanic tephra tends to persist and remain remobilized for years in arid and semi-arid environments, which can be problematic. Healthy wet meadow-wetlands developed in the bottom valleys of Northern Patagonia, Argentina, offer a natural solution for mitigating volcanic tephra impacts. By combining existing geographic information (North Patagonia wetland distribution map and tephra fallout deposit map), the extent of wet meadows affected by the 2011 Puyehue-Cordón Caulle Volcanic Complex (PCCVC) volcano was calculated. The regional amount of available forage in the aftermath of the eruption was estimated through field assessments of aerial net primary production (ANPP); this was conducted during the first peak of plant growth after the PCCVC volcanic event in 5 m x 5 m paired plots, both with and without manually removed tephra a month after the event. To compare the tephra effect on vegetation type throughout time, normalized vegetation index (NDVI) was used to monitor plant activity two years before, the following year, and five years after the PCCVC event in wet meadows and surrounding steppes. In addition, the regional amount of tephra removed from the environment and stabilized in the soil was assessed using prior research findings of ash immobilization and stabilization within meadow soil profiles five years after the PCCVC event. Around 106,000 ha (52%) of North Patagonian meadows were identified to be exposed to volcanic hazard. The plant growing season following the eruption generated, on average, 3929±2146 kg DM ha−1, indicating an active functional wet meadow recovery despite a 25-20% reduction in ANPP due to the tephra effect. NDVI data supported these findings, with the historical maximum level (0.46±0.02) being restored the year following the event, while surrounding steppes recovered at least three years after. Healthy wet meadows mitigated the adverse effects of around 2279 tons of regional tephra, while simultaneously providing nearly half a billion tons of fodder production the year following the eruption- a critical period of cattle food scarcity. These findings highlight the reduction of negative impacts following recurrent volcanic eruptions and underscore the positive effects of conserving, restoring, and sustainably managing wetlands as a Nature-Based Solution for Disaster Risk Reduction.
Nearly two decades ago, the Indian Ocean tsunami created a devastating human tragedy, leaving many questions in its wake as to the role that mangroves may have played in saving lives and livelihoods. Over the following decade, these questions led to the creation of a new field of study: the role of ecosystems in disaster risk reduction, or Eco-DRR. After 2020, Eco-DRR became quasi-synonymous with ‘Nature-based Solutions for disaster risk reduction’, with a few notable differences. What changed as a result of the Indian Ocean tsunami was an increased awareness that ecosystems could – and should – be part of discourse and portfolios of investments in disaster risk reduction (DRR). Over the next two decades, this awareness grew in three phases: 1) 2005–2014: the ‘convincing stage’; 2) 2015–2020: the ‘mainstreaming stage’ 3) 2020: ‘the blue-printing stage’. This collection of articles highlights research on the evidence of the effectiveness of ecosystem approaches for DRR, while addressing the above question: “how to implement”?
The term carbon (C) sequestration has not just become a buzzword but is something of a siren’s call to scientific communicators and media outlets. Carbon sequestration is the removal of C from the atmosphere and the storage, for example, in soil. It has the potential to partially compensate for anthropogenic greenhouse gas emissions and is, therefore, an important piece in the global climate change mitigation puzzle. However, the term C sequestration is often used misleadingly and, while likely unintentional, can lead to the perpetuation of biased conclusions and exaggerated expectations about its contribution to climate change mitigation efforts. Soils have considerable potential to take up C but many are also in a state of continuous loss. In such soils, measures to build up soil C may only lead to a reduction in C losses (C loss mitigation) rather than result in real C sequestration and negative emissions. In an examination of 100 recent peer-reviewed papers on topics surrounding soil C, only 4% were found to have used the term C sequestration correctly. Furthermore, 13% of the papers equated C sequestration with C stocks. The review, further, revealed that measures leading to C sequestration will not always result in climate change mitigation when non-CO2 greenhouse gases and leakage are taken into consideration. This paper highlights potential pitfalls when using the term C sequestration incorrectly and calls for accurate usage of this term going forward. Revised and new terms are suggested to distinguish clearly between C sequestration in soils, SOC loss mitigation, negative emissions, climate change mitigation, SOC storage, and SOC accrual to avoid miscommunication among scientists and stakeholder groups in future.
Improved knowledge of glacial-to-interglacial global temperature change yields Charney (fast-feedback) equilibrium climate sensitivity 1.2 ± 0.3°C (2σ) per W/m2, which is 4.8°C ± 1.2°C for doubled CO2. Consistent analysis of temperature over the full Cenozoic era—including ‘slow’ feedbacks by ice sheets and trace gases—supports this sensitivity and implies that CO2 was 300–350 ppm in the Pliocene and about 450 ppm at transition to a nearly ice-free planet, exposing unrealistic lethargy of ice sheet models. Equilibrium global warming for today’s GHG amount is 10°C, which is reduced to 8°C by today’s human-made aerosols. Equilibrium warming is not ‘committed’ warming; rapid phaseout of GHG emissions would prevent most equilibrium warming from occurring. However, decline of aerosol emissions since 2010 should increase the 1970–2010 global warming rate of 0.18°C per decade to a post-2010 rate of at least 0.27°C per decade. Thus, under the present geopolitical approach to GHG emissions, global warming will exceed 1.5°C in the 2020s and 2°C before 2050. Impacts on people and nature will accelerate as global warming increases hydrologic (weather) extremes. The enormity of consequences demands a return to Holocene-level global temperature. Required actions include: (1) a global increasing price on GHG emissions accompanied by development of abundant, affordable, dispatchable clean energy, (2) East-West cooperation in a way that accommodates developing world needs, and (3) intervention with Earth’s radiation imbalance to phase down today’s massive human-made ‘geo-transformation’ of Earth’s climate. Current political crises present an opportunity for reset, especially if young people can grasp their situation.
The EU Soil Strategy 2030 aims to increase soil organic carbon (SOC) in agricultural land to enhance soil health and support biodiversity as well as to offset greenhouse gas emissions through soil carbon sequestration. Therefore, the quantification of current SOC stocks and the spatial identification of the main drivers of SOC changes is paramount in the preparation of agricultural policies aimed at enhancing the resilience of agricultural systems in the EU. In this context, changes of SOC stocks (Δ SOCs) for the EU + UK between 2009 and 2018 were estimated by fitting a quantile generalized additive model (qGAM) on data obtained from the revisited points of the Land Use/Land Cover Area Frame Survey (LUCAS) performed in 2009, 2015 and 2018. The analysis of the partial effects derived from the fitted qGAM model shows that land use and land use change observed in the 2009, 2015 and 2018 LUCAS campaigns (i.e. continuous grassland [GGG] or cropland [CCC], conversion grassland to cropland (GGC or GCC) and vice versa [CGG or CCG]) was one of the main drivers of SOC changes. The CCC was the factor that contributed to the lowest negative change on Δ SOC with an estimated partial effect of −0.04 ± 0.01 g C kg−1 year−1, while the GGG the highest positive change with an estimated partial effect of 0.49 ± 0.02 g C kg−1 year−1. This confirms the C sequestration potential of converting cropland to grassland. However, it is important to consider that local soil and environmental conditions may either diminish or enhance the grassland’s positive effect on soil C storage. In the EU + UK, the estimated current (2018) topsoil (0–20 cm) SOC stock in agricultural land below 1000 m a.s.l was 9.3 Gt, with a Δ SOC of −0.75% in the period 2009–2018. The highest estimated SOC losses were concentrated in central-northern countries, while marginal losses were observed in the southeast.
Although increased temperatures are known to reinforce the effects of habitat destruction at local to landscape scales, evidence of their additive or interactive effects is limited, particularly over larger spatial extents and longer timescales. To address these deficiencies, we created a dataset of land-use changes over 75 years, documenting the loss of over half (>3000 km2) the semi-natural grassland of Great Britain. Pairing this dataset with climate change data, we tested for relationships to distribution changes in birds, butterflies, macromoths, and plants (n = 1192 species total). We show that individual or additive effects of climate warming and land conversion unambiguously increased persistence probability for 40% of species, and decreased it for 12%, and these effects were reflected in both range contractions and expansions. Interactive effects were relatively rare, being detected in less than 1 in 5 species, and their overall effect on extinction risk was often weak. Such individualistic responses emphasise the importance of including species-level information in policies targeting biodiversity and climate adaptation.