Peer-reviewed publications

Key messages

There are three approaches to private sector commitments on zero deforestation: individual company or group-level adoption of voluntary standards; sector-wide supply chain-based interventions; and mixed supply chain and territorial initiatives at jurisdictional level.

The main implementation challenges of these approaches are the limits of voluntary standards, traceability systems that are difficult to implement, selective actions that cannot deliver at scale, associated leakage effects, and persistence of segmented supply chains.

Approaches have evolved to deal with such challenges, however progress requires committed companies to increase implementation efforts, other supply chain actors to adhere to commitments, and governments to harness the potential of jurisdictional approaches.

This chapter provides a general description of benefits and consideration of economic valuation of those benefits that can be derived from coastal habitats that store and sequester carbon (C): seagrass meadows and wetlands, which include marshes and mangrove forests. It presents examples of important ecosystem services (ESs) and their valuation. Before assessing an economic value to these ESs at different spatial scales, it is critical to obtain accurate estimates of mangrove biomass and C stocks for mangrove ecotypes. During the 19th century, coastal wetlands often were considered a nuisance environment and perceived as competing against other human uses that serve immediate economic needs. Several attempts have been made to calculate economic values for these ESs globally, but economic valuation studies have estimated more credible results when focused on a smaller area where marginal values of some of these ESs can be calculated.

Since the 1990s, the Intergovernmental Panel on Climate Change (IPCC) has used global assessments of vulnerability to inform investment and action against the effects of climate change. Beyond the IPCC, others have undertaken global assessments to understand the vulnerability of coastal areas to climate change. Eight global vulnerability assessments are compared to understand similarities and differences in their results and the metrics used to construct a vulnerability index. Variations in objectives, conceptualizations of vulnerability, operationalization of the concepts, scope and depth of data drawn upon lead to contradictory rankings of priority areas for climate action between assessments. The increased complexity and scope of indicators make it difficult to untangle the root causes of such differences in rankings. It is also difficult to identify the degree to which climate change influences vulnerability rankings compared to other factors such as local environmental conditions and the capacity of populations to deal with environmental change. The way to undertake global assessments needs to be reshaped to better inform planning of international development along different objectives. Global level assessments need to be simplified and harmonized to better isolate the impact of climate change specific drivers. Decision-makers would make better use of such global assessments as scoping studies rather than expect comprehensive and robust priorities for investment. Such scoping studies can help target locations where supplementary, in-depth local analyses need to be conducted. At the local level, the possibility to collect context-specific information, particularly on adaptive capacity, allows the robust assessment of vulnerability.

Social conflicts related to biodiversity conservation and adaptation policy to climate change in coastal areas illustrate the need to reinforce understanding of the “matters of concern” as well as the “matters of fact”. In this paper, we argue that we must rethink adaptation from a new perspective, considering that humans together function as both ecological actors and social actors. Using international examples from the UNESCO world biosphere reserve network, we show that an ontological perspective may provide a simple and compact way to think about coupled infrastructure systems and systematic formalism, allowing for understanding of the relational matrix between actors, institutions and ecosystems. We contend that our formalism responds to three challenges. First, it encompasses the different regional contexts and policies that rely on the same ontology. Second, it provides a method to relate any local adaptation plan to the conservation paradigms that originate from the ecological modernization of policies. Third, it facilitates the discovery of drivers and processes involved in adaptation and management regime shifts by highlighting the way contextual factors configure, determine the structure of the action situation of the Institutional Analysis and Development framework (IAD) (Ostrom 2005), and how it operates.

Tourism may benefit conservation, but some wildlife viewing practices threaten the sustainability of both business and conservation initiatives. In north-west Namibia, conservation-oriented tourism provides tourists with an opportunity to encounter the critically-endangered black rhinoceros Diceros bicornis on foot. We used 123 tourist-rhinoceros encounters and employed a statistical modeling approach to: (1) identify the characteristics of human-rhinoceros encounters that caused rhinoceros disturbance and displacement; and (2) design rhinoceros-human encounter guidelines that improve sustainability. A model-averaging, information-theoretic approach identified tourist approach distance, viewing time and individual encounter exposure as the most significant predictors of rhinoceros disturbance level. A suite of rhinoceros viewing scenarios were modeled for acceptable disturbance risks, and adopted as a rhinoceros viewing policy. The policy reduced encounter displacements by 80% while maintaining a 95% positive feedback rating from guests. We demonstrate an evidence-based, policy-oriented management approach can help improve tourism's contribution towards the conservation of an endangered species.

Tourism may benefit conservation, but some wildlife viewing practices threaten the sustainability of both business and conservation initiatives. In north-west Namibia, conservation-oriented tourism provides tourists with an opportunity to encounter the critically-endangered black rhinoceros Diceros bicornis on foot. We used 123 tourist-rhinoceros encounters and employed a statistical modeling approach to: (1) identify the characteristics of human-rhinoceros encounters that caused rhinoceros disturbance and displacement; and (2) design rhinoceros-human encounter guidelines that improve sustainability. A model-averaging, information-theoretic approach identified tourist approach distance, viewing time and individual encounter exposure as the most significant predictors of rhinoceros disturbance level. A suite of rhinoceros viewing scenarios were modeled for acceptable disturbance risks, and adopted as a rhinoceros viewing policy. The policy reduced encounter displacements by 80% while maintaining a 95% positive feedback rating from guests. We demonstrate an evidence-based, policy-oriented management approach can help improve tourism's contribution towards the conservation of an endangered species.

Mangroves, seagrass meadows, and salt marshes, collectively termed "Blue Forests," are counted among the most valuable and productive coastal ecosystems on the planet. A recent literature review of the Blue Forest valuation research identified mangroves as the most frequently analyzed of these ecosystems, yet the literature demonstrates several deficits in terms of geographic location of studies, methods used to value the services, and most notably, a lack of valuation for cultural services. To better understand this, we analyzed the studies dealing specifically with mangroves from the original literature review to quantify what has been valued, where, by which methods, and the variation in the published values. We then use this information to synthesize our current level of knowledge on the type and value of services provided by mangroves, discuss data gaps, and address specifically the collection of data relevant to cultural ecosystem services (CES).

The food system is a major driver of climate change, changes in land use, depletion of freshwater resources, and pollution of aquatic and terrestrial ecosystems through excessive nitrogen and phosphorus inputs. Here we show that between 2010 and 2050, as a result of expected changes in population and income levels, the environmental effects of the food system could increase by 50-90% in the absence of technological changes and dedicated mitigation measures, reaching levels that are beyond the planetary boundaries that define a safe operating space for humanity. We analyse several options for reducing the environmental effects of the food system, including dietary changes towards healthier, more plant-based diets, improvements in technologies and management, and reductions in food loss and waste. We find that no single measure is enough to keep these effects within all planetary boundaries simultaneously, and that a synergistic combination of measures will be needed to sufficiently mitigate the projected increase in environmental pressures.

Incremental adaptation may be inadequate to deal with rapid shifts and tipping points for food production under climate change. The concepts of transformative and transformational adaptation have emerged in recent years to address the need for major, non-marginal transitions in sectors, such as agriculture in response to climate change. However, there is less empirical evidence of transformation in practice. Here we use a simple semi-quantitative definition to identify recorded cases of transformational adaptation in response to climate change. A structured search of academic literature found 23 empirical case studies that meet our criteria for transformation of agriculture under climate change: a response to climate risks along with a redistribution of at least a third in the primary factors of production (land, labor, capital) or the outputs and outcomes of production over a time period of 25 years or less.

The time of day that nestlings fledge from a nest is thought to be shaped by predation risk and energetics. To minimize predation risk, fledging is predicted to start as early in the day as possible so that nestlings can maximize time outside the nest to find a safe place to stay before nightfall. Fledging times are predicted to be tightly grouped and to not be affected by the number of nestlings, given that all nestlings are responding to the same relative risk of predation. Conversely, energetic considerations predict that fledging time of day should vary so that nestlings can maximize energy intake before having to forage for themselves. However, data to evaluate the relative importance of these drivers in grassland birds are scarce because of the difficulty of observing nestlings as they fledge. We used nest surveillance video from 178 nests to evaluate how the initiation and duration of fledging varied among 7 grassland passerine species, as well as by the number of nestlings in the nest and fledging date. Fledging initiation varied most strongly by species, with some effects of date. Across species, the median start time of fledging was 4.55 hr after sunrise. Fledging before the solstice started 30 min earlier compared to fledging at or after the solstice. Fledging duration increased with number of nestlings in the nest and was spread over >1 day in 21% of nests. While our results primarily supported the hypothesis that fledging is motivated by energetic considerations, additional data on basic life history traits and behavior will be needed to fully understand how fledging grassland birds balance energetics against predation risk.