Peer-reviewed publications

Projected climate and environmental change are expected to increase the pressure on global freshwater resources. To prepare for and cope with the related risks, stakeholders need to devise plans for sustainable management of river systems, which in turn require the identification of management-appropriate operational units, such as groups of rivers that share similar environmental and biological characteristics. Ideally, these units are of manageable size and biotically or abiotically distinguishable across a variety of river types. Here, we aim to address this need by presenting a new global river classification framework (GloRiC) to establish a common vocabulary and standardized approach to the development of globally comprehensive and integrated river classifications that can be tailored to different goals and requirements.

Voluntary sustainability standards (VSS) are stakeholder-derived principles with measurable and enforceable criteria to promote sustainable production outcomes. While institutional commitments to use VSS to meet sustainable procurement policies have grown rapidly over the past decade, we still have relatively little understanding of the (i) direct environmental benefits of large-scale VSS adoption; (ii) potential perverse indirect impacts of adoption; and (iii) implementation pathways. Here, we illustrate and address these knowledge gaps using an ecosystem service modeling and scenario analysis of Bonsucro, the leading VSS for sugarcane. We find that global compliance with the Bonsucro environmental standards would reduce current sugarcane production area (-24%), net tonnage (-11%), irrigation water use (-65%), nutrient loading (-34%), and greenhouse gas emissions from cultivation (-51%). Under a scenario of doubled global sugarcane production, Bonsucro adoption would further limit water use and greenhouse gas emissions by preventing sugarcane expansion into water-stressed and high-carbon stock ecosystems. This outcome was achieved via expansion largely on existing agricultural lands. However, displacement of other crops could drive detrimental impacts from indirect land use. We find that over half of the potential direct environmental benefits of Bonsucro standards under the doubling scenario could be achieved by targeting adoption in just 10% of global sugarcane production areas. However, designing policy that generates the most environmentally beneficial Bonsucro adoption pathway requires a better understanding of the economic and social costs of VSS adoption. Finally, we suggest research directions to advance sustainable consumption and production.

This study provides evidence that a heliophilic butterfly, the Glanville fritillary (Melitaea cinxia) has adapted differently to environmental variation across latitudes and elevations. 2. In cool air, basking M. cinxia orient themselves perpendicular to the sun's rays to gain heat and take off. During flight, solar heating is reduced because orientation perpendicular to the sun is no longer possible and convective cooling occurs. Consequently, M. cinxia have been shown to suffer net heat loss in flight, even in full sunshine. When flight duration is restricted in this way, the takeoff temperature becomes an important thermal adaptation. 3. Using a thermal imaging camera, takeoff temperatures were measured in experimental butterflies. Butterflies from the northern range limit in Finland took flight at slightly hotter temperatures than butterflies from the southern limit in Spain, and much hotter than butterflies from the elevational limit (1900-2300 m) in the French Alps. Butterflies from low-elevation populations in southern France also took off much hotter than did the nearby Alpine population. 4. These results suggest that the influence of elevation is different from that of latitude in more respects than ambient temperature. Values of solar irradiance in the butterflies' flight season in each region show that insects from the coolest habitats, Finland and the Alps, experienced similar solar irradiance during basking, but that Finns experienced much lower irradiance in flight. This difference may have favored Finnish butterflies evolving higher takeoff temperatures than Alpine butterflies that also flew in cool air but benefited from more intense radiant energy after takeoff.

Food systems have the potential to nurture human health and support environmental sustainability; however, they are currently threatening both. Providing a growing global population with healthy diets from sustainable food systems is an immediate challenge. Although global food production of calories has kept pace with population growth, more than 820 million people have insufficient food and many more consume low-quality diets that cause micronutrient deficiencies and contribute to a substantial rise in the incidence of diet-related obesity and diet-related non-communicable diseases, including coronary heart disease, stroke, and diabetes. Unhealthy diets pose a greater risk to morbidity and mortality than does unsafe sex, and alcohol, drug, and tobacco use combined. Because much of the world's population is inadequately nourished and many environmental systems and processes are pushed beyond safe boundaries by food production, a global transformation of the food system is urgently needed.

The forest landscapes of the Greater Mekong Subregion (GMS) are changing dramatically, with a multitude of impacts from local to global levels. These changes invariably have their foundations in forest governance. The aim of this paper is to assess perceptions of key stakeholders regarding the state of forest governance in the countries of the GMS. The work is based on a quantitative and qualitative analysis of the perceptions of forest governance in the five GMS countries, involving 762 representatives from government, civil society, news media, and rural communities. The work identified many challenges to good forest governance in the countries in the region, as well as noting reasons for optimism. Generally speaking, there was a feeling that the policies, legislation, and institutional frameworks were supportive, but there are numerous challenges in terms of implementation, enforcement, and compliance. The work also presents a program of activities recommended by the research participants to address governance challenges and opportunities in the GMS countries. These include the development of a forest governance monitoring system, and initiatives that support informed decision-making by forest product consumers in the region as well as the implementation of a capacity development program for non-state actors (e.g., civil society, news media) to ensure they are more able to support the diverse, and often demanding, forest governance initiatives.

Policymakers and investors have perceived securing soil organic carbon as too difficult, with uncertain returns. But new technical, policy and financial opportunities offer hope for rapid progress. Growing visibility and international frameworks for soil organic carbon are not yet matched by investment and action at scale. Soils, mostly privately owned but delivering public goods, are managed under a miscellany of governance arrangements, from local to global1. While there have been compelling calls for action on soils, diverse protagonists across business1,2, governments and civil society who seek to secure soil organic carbon recognize barriers beyond their individual reach—and hence an urgent need for a cross-sectoral global agenda.

Increasing human populations around the global coastline have caused extensive loss, degradation and fragmentation of coastal ecosystems, threatening the delivery of important ecosystem services. As a result, alarming losses of mangrove, coral reef, seagrass, kelp forest and coastal marsh ecosystems have occurred. However, owing to the difficulty of mapping intertidal areas globally, the distribution and status of tidal flats–one of the most extensive coastal ecosystems–remain unknown. Here we present an analysis of over 700,000 satellite images that maps the global extent of and change in tidal flats over the course of 33 years (1984-2016). We find that tidal flats, defined as sand, rock or mud flats that undergo regular tidal inundation, occupy at least 127,921 km2(124,286-131,821 km2, 95% confidence interval). About 70% of the global extent of tidal flats is found in three continents (Asia (44% of total), North America (15.5% of total) and South America (11% of total)), with 49.2% being concentrated in just eight countries (Indonesia, China, Australia, the United States, Canada, India, Brazil and Myanmar). For regions with sufficient data to develop a consistent multi-decadal time series–which included East Asia, the Middle East and North America–we estimate that 16.02% (15.62-16.47%, 95% confidence interval) of tidal flats were lost between 1984 and 2016. Extensive degradation from coastal development, reduced sediment delivery from major rivers, sinking of riverine deltas, increased coastal erosion and sea-level rise signal a continuing negative trajectory for tidal flat ecosystems around the world. Our high-spatial-resolution dataset delivers global maps of tidal flats, which substantially advances our understanding of the distribution, trajectory and status of these poorly known coastal ecosystems.

Many human populations are dependent on marine ecosystems for a range of benefits but we understand little about where and to what degree people rely on these ecosystem services. We created a new conceptual model to map the degree of human dependence on marine ecosystems based on the magnitude of the benefit, susceptibility of people to a loss of that benefit, and the availability of alternatives. We focused on mapping nutritional, economic, and coastal protection dependence, but our model is repeatable, scalable, applicable to other ecosystems, and designed to incorporate additional services and data. Here we show that dependence was highest for Pacific and Indian Ocean island nations and several West African countries. More than 775 million people live in areas with relatively high dependence scores. By identifying where and how people are dependent on marine ecosystems, our framework can be used to design more effective large-scale management and policy interventions.

The links between plantation expansion and deforestation in Borneo are debated. We used satellite imagery to map annual loss of old-growth forests, expansion of industrial plantations (oil palm and pulpwood), and their overlap in Borneo from 2001 to 2017. In 17 years, forest area declined by 14% (6.04 Mha), including 3.06 Mha of forest ultimately converted into industrial plantations. Plantations expanded by 170% (6.20 Mha: 88% oil palm; 12% pulpwood). Most forests converted to plantations were cleared and planted in the same year (92% 2.83 Mha). Annual forest loss generally increased before peaking in 2016 (0.61 Mha) and declining sharply in 2017 (0.25 Mha). After peaks in 2009 and 2012, plantation expansion and associated forest conversion have been declining in Indonesia and Malaysia. Annual plantation expansion is positively correlated with annual forest loss in both countries. The correlation vanishes when we consider plantation expansion versus forests that are cleared but not converted to plantations. The price of crude palm oil is positively correlated with plantation expansion in the following year in Indonesian (not Malaysian) Borneo. Low palm oil prices, wet conditions, and improved fire prevention all likely contributed to reduced 2017 deforestation. Oversight of company conduct requires transparent concession ownership.

Non-state and subnational climate actors have become central to global climate change governance. Quantitatively assessing climate mitigation undertaken by these entities is critical to understand the credibility of this trend. In this Perspective, we make recommendations regarding five main areas of research and methodological development related to evaluating non-state and subnational climate actions: defining clear boundaries and terminology; use of common methodologies to aggregate and assess non-state and subnational contributions; systematically dealing with issues of overlap; estimating the likelihood of implementation; and addressing data gaps.