• Energy Research

Land use is central to addressing sustainability issues, including biodiversity conservation, climate change, food security, poverty alleviation, and sustainable energy. In this paper, we synthesize knowledge accumulated in land system science, the integrated study of terrestrial social-ecological systems, into 10 hard truths that have strong, general, empirical support. These facts help to explain the challenges of achieving sustainability in land use and thus also point toward solutions. The 10 facts are as follows: 1) Meanings and values of land are socially constructed and contested; 2) land systems exhibit complex behaviors with abrupt, hard-to-predict changes; 3) irreversible changes and path dependence are common features of land systems; 4) some land uses have a small footprint but very large impacts; 5) drivers and impacts of land-use change are globally interconnected and spill over to distant locations; 6) humanity lives on a used planet where all land provides benefits to societies; 7) land-use change usually entails trade-offs between different benefits—"win–wins" are thus rare; 8) land tenure and land-use claims are often unclear, overlapping, and contested; 9) the benefits and burdens from land are unequally distributed; and 10) land users have multiple, sometimes conflicting, ideas of what social and environmental justice entails. The facts have implications for governance, but do not provide fixed answers. Instead they constitute a set of core principles which can guide scientists, policy makers, and practitioners toward meeting sustainability challenges in land use.

In this study, we produced a spatially explicit diagnosis of the deforestation hotspots and future climate risk (2050) of cocoa producing areas, zooming into the top 8 cocoa exporting countries and the main global cocoa traders. Cocoa-driven deforestation often co-occurs with deforestation driven by other agri-commodities, and thus needs to be tackled jointly. Climate risk will be substantially increased in Cote d'Ivoire and Ghana, the two most important suppliers of cocoa, which may lead to supply failures and severe socio-economic impacts if left unaddressed. Climate risk and deforestation have a high spatial variability between and within countries, calling for geographically differentiated approaches to mitigation and adaptation. Large transnational traders depending heavily on West African supplies, as well as the regionally based exporting farmer cooperatives and domestic firms, will be affected by the increased climate risk in that region. Traders operating in Latin America and Southeast Asia might only face a modest increase in climate risk, with subregional exceptions. These results raise concerns about the validity of sustainability commitments made by companies and other sector initiatives, which focus on single commodities and fail to consider the diversity of actors adding pressure on landscapes. Tackling these issues requires a collaborative effort from various sectors and stakeholders involved in land use decisions to prevent the geographical displacement of negative impacts, prioritize urgent action, and implement these changes efficiently and in a coordinated manner. Further, sustainability commitments often neglect climate change adaptation, with agroforestry and climate smart agriculture initiatives primarily focusing on carbon reductions and increased farmer income, paying less attention to farm practices that reduce cocoa vulnerability.

The increasing expansion of cropland is major driver of global carbon emissions and biodiversity loss. However, predicting plausible future global distributions of croplands remains challenging. Here, we show that, in general, existing global data aligned with classical economic theories of expansion explain the current (1992) global extent of cropland reasonably well, but not recent expansion (1992-2015). Deviations from models of cropland extent in 1992 ("frontierness") can be used to improve global models of recent expansion, most likely as these deviations are a proxy for cropland expansion under frontier conditions where classical economic theories of expansion are less applicable. Frontierness is insensitive to the land cover dataset used and is particularly effective in improving models that include mosaic land cover classes and the largely smallholder-driven frontier expansion occurring in such areas. Our findings have important implications as the frontierness approach offers a straightforward way to improve global land use change models.

Summary Commodity trade is central to the global economy but is also associated with socio-environmental impacts, for example, deforestation, especially in producer countries. It is crucial to understand how geographic sourcing patterns of commodities and commercial relationships between places and actors influence land-use dynamics, socio-economic development, and environmental degradation. Here, we propose a concept and methodological approach to analyze the geographic stickiness of commodity supply chains, which is the maintenance of supply network configurations over time and across perturbations. We showcase policy-relevant metrics for all Brazilian soy exports between 2003 and 2017, using high-resolution supply chain data from www.trase.earth . We find that the Brazilian soy traders with the largest market share exhibit stickier geographic sourcing patterns, and that the supply network configurations between production places and traders become increasingly sticky in subsequent years. Understanding trade stickiness is crucial for supply chain accountability, because it directly affects the effectiveness of zero-deforestation commitments.

In order to improve sustainability and design adequate management strategies in threatened tropical forests, integrated assessments of the use of ecosystem services are needed, combining biophysical, social, and economic approaches. In particular, no integrated ecosystem services (ES) assessment has been conducted in Central Africa, where rural communities deeply depend on forests in a high-poverty context. Here, we aimed to quantify the use of ES provided by tropical forests to local populations in the Dja area (Cameroon), identify its determinants and evaluate its sustainability. We conducted various interviews and field surveys with 133 households in three villages, focusing on three provisioning services (bushmeat, firewood, and timber), and five cultural services (cultural heritage, inspiration, spiritual experience, recreation, and education). Local populations consumed a mean of 56 kg of bushmeat/person/year (hunting zones covering on average 213 km2), 1.17 m3 of firewood/person/year (collection zones covering on average 4 km2), and 0.03 m3 of timber/person/year. Between 25% and 86% of respondents considered cultural services as important. The use of ES was mainly influenced by population size, deforestation rate, and forest allocations, whereas the influence of socio-demographic characteristics of households remained limited to slight differences between Baka and Bantu people. We conclude that the consumption of firewood and timber is sustainable, whereas high hunting pressure has resulted in severe defaunation in the area due to the large decline in the abundance and biomass of forest mammals hunted for bushmeat by local populations.