Mangrove restoration has become a popular strategy to ensure the critical functions and economic benefits of this ecosystem. This study conducts a meta-analysis of the peer-reviewed literature on the outcomes of mangrove restoration. On aggregate, restored mangroves provide higher ecosystem functions than unvegetated tidal flats but lower than natural mangrove stands (respectively RR’ = 0.43, 95%CIs = 0.23 to 0.63; RR’ = −0.21, 95%CIs = −0.34 to −0.08), while they perform on par with naturally-regenerated mangroves and degraded mangroves. However, restoration outcomes vary widely between functions and comparative bases, and are mediated by factors such as restoration age, species, and restoration method. Furthermore, mangrove restoration offers positive benefit-cost ratios ranging from 10.50 to 6.83 under variable discount rates (−2% to 8%), suggesting that mangrove restoration is a cost-effective form of ecosystem management. Overall, the results suggest that mangrove restoration has substantial potential to contribute to multiple policy objectives related to biodiversity conservation, climate change mitigation and sustainable development.

Population ageing and shrinking are demographic phenomena with far-reaching implications for sustainability in the current context of extensive and rapid urbanization. This Perspective rationalizes their interface by (a) identifying the challenges and opportunities that ageing and shrinking urban populations will have for implementing the sustainable development goals (SDGs), and (b) discussing some emerging interventions to capitalise on the opportunities and reduce the challenges to achieving sustainability. We argue that a diverse set of context-specific technological, socioeconomic, institutional and governance interventions would be needed to leverage effectively the opportunities and minimize the risks posed by ageing and shrinking urban populations for long-term sustainability.

Malnutrition in all forms, ranging from undernourishment to obesity and associated diet-related diseases, is one of the leading causes of death worldwide, while food systems often have major environmental impacts. Rapid global population growth and increases in demands for food and changes in dietary habits create challenges to provide universal access to healthy food without creating negative environmental, economic, and social impacts. This article discusses opportunities for and challenges to sustainable food systems from a human health perspective by making the case for avoiding the transition to unhealthy less sustainable diets (using India as an exemplar), reducing food waste by changing consumer behaviour (with examples from Japan), and using innovations and new technologies to reduce the environmental impact of healthy food production. The article touches upon two of the challenges to achieving healthy sustainable diets for a global population, i.e., reduction on the yield and nutritional quality of crops (in particular vegetables and fruits) due to climate change; and trade-offs between food production and industrial crops. There is an urgent need to develop and implement policies and practices that provide universal access to healthy food choices for a growing world population, whilst reducing the environmental footprint of the global food system.