Planetary health research digest
Authors: Sam Hinsley
Journal: The Lancet Planetary Health (2020)

Household energy supplies help to maintain comfortable temperatures, ventilate homes and preserve food in the face of environmental stressors. However, many households face energy insecurity, putting them at risk of a range of health threats. In order to better characterise who is most at risk of energy insecurity around the world and the mechanisms by which it affects wellbeing, Sonal Jessel (Columbia University Mailman School of Public Health, USA) and co-authors conducted a review of the literature on the physical, economic, and health dimensions of this problem. They then develop a new model to help understand energy insecurity. A key conclusion is that the people most affected by energy insecurity are usually those who are already facing other hardships, such as those resulting from racial, socioeconomic, or gender inequality. Future research will need to account for energy insecurity as a mediator of social inequality, as well as the effects of climate change. Global food production relies heavily on breadbasket regions, which produce disproportionately large shares of global food supplies. Crop failure in these regions due to climate extremes is therefore a key concern for global food security. While failure in a single breadbasket can often be compensated by trade or crop reserves, simultaneous failures are harder to absorb. Franziska Gaupp (International Institute for Applied Systems Analysis, Austria) and co-authors investigate how the changing climate has affected the risk of crop failures in global breadbasket regions between 1967 and 2012. Using data on crop yields and climate conditions to define adverse growing conditions for four staple crops, they found substantial increases in the risk of simultaneous breadbasket failures for wheat, maize, and soybeans, while the risk was decreased for rice. Modelling the spatial dependence of climate between regions indicated that climate conditions in one region could exacerbate or mitigate the risk of breadbasket failure posed to other regions, further illustrating the complexity of the processes involved. Such analyses could help to inform resiliency or contingency programmes to avoid future food system shocks. The global stock of residential buildings is rapidly growing. To reduce waste, materials from older buildings could be repurposed in the construction of newer ones. The scaling up of building material recycling requires systematic estimates of the current stocks of these materials. Sylvia Marinova (Leiden University, the Netherlands) and co-authors address this knowledge gap by compiling the first global database of building material intensities for residential buildings and test its usefulness for modelling future scenarios of housing and material stocks. They construct the database using the findings from previous smaller scale studies and test its applicability by modelling changes in stocks from 1970–2050 under a middle-of-the road scenario for future development. While housing and material stocks were predicted to continue growing slowly in high-income countries, China led in overall growth, particularly for in-use steel stocks, with evidence of this growth plateauing by around 2050. In other rapidly developing regions such as India and southeast Asia this growth in housing stocks has recently started to increase and is projected to continue rising past 2050. By making the database available, the authors offer a first step towards improved recycling of in-use building materials. Since the publication of the Summary for Policymakers of the IPBES Global Assessment in May, 2019, the threats to biodiversity have garnered increased attention. Sandra Diaz (Instituto Multidisciplinario de Biología Vegetal, Argentina) and co-authors summarise the key findings of the IPBES assessment and bring it up to date with evidence published since the end of the literature review phase. They outline the staggering scale of human impacts on biodiversity, not just in terms of the numbers of species threatened with extinction, but also the declines in nature's ability to contribute to human quality of life. By reviewing the direct and indirect drivers of environmental change and the impact of these changes on progress towards human and environmental wellbeing targets, such as the SDGs, the authors define key leverage points for effecting positive change towards a more sustainable future. They argue that use of these levers, such as incentivisation of sustainable behaviour and enhancing intersectoral collaboration, could still avoid and even reverse some of the harms done to Earths biodiversity; but transformational changes are required.