Research articles

Cryptocurrency mining requires extensive energy consumption for computers to verify the blockchain and generate new currency. This analysis compares several cryptocurrencies and metals in terms of the amount of energy needed to create one US dollar of value, as well as the carbon emissions that may be directly attributable to cryptocurrency mining.

Provision of electricity in sub-Saharan Africa is often affected by outages leading to increased use of backup diesel generators. In this study, the authors estimate the air emissions, consumer costs and fossil energy consumption resulting from the use of such generators.

The net environmental costs of rare earths production in China, the largest producer, are estimated to be almost US$15 billion. Scenarios show that the largest reduction in environmental impact can be achieved by tackling illegal mining.

Village chickens are commonplace among smallholder communities, but mortality is high. This study compares two regions in Ethiopia and finds that unique adaptations, including traits and parasite burdens, reflect distinct gene pools likely shaped by human-driven selection. Results suggest sustainable interventions for village chickens should be locally tailored.

Most wildlife lives outside protected areas, creating potential conflicts with humans. This study assesses potential trade-offs between wildlife and livestock management in an East African savanna, finding potential ecological and economic benefits from integrating the two.

Machine learning using big data can enhance environmental law monitoring. Applied to the US Clean Water Act, such methods can help public agencies to increase the likelihood of inspecting non-compliant facilities up to sevenfold.

Measures to adapt coastal areas to tsunamis risk creating greater vulnerabilities owing to a false sense of security. Hard-adaptive projects like seawalls must be considered within an assessment of human behaviour and feedback loops.

High-yield farming systems have the potential to spare non-farmed land for other uses (such as nature conservation), but raise concerns about their other environmental impacts (such as greenhouse gas emissions and soil erosion). This study argues such impacts should be measured per unit of production and shows that viewed this way, some land-efficient systems have less impact than lower-yielding alternatives.

Understanding the sources of particulate matter responsible for extreme air pollution and climate change is critical for designing adequate policies to protect the wellbeing of citizens. This study shows that extraordinary levels of particulate matter with diameter smaller than 1 µm were observed in Dublin in November 2016 and January 2017 and can be attributed to emissions from residential burning of peat and wood, often promoted as ‘slow renewables’.

Focusing on China’s six natural gas sources and three end-use gas-forcoalsubstitution strategies in 2020, this study shows that, except for coal-based synthetic gas, replacement of coalwith gas usually has air–carbon–water co-benefits, although with air–water trade-offs in the magnitude ofimprovement.

Cobalt is used in rechargeable batteries, and half the world’s supply comes from one district in the Democratic Republic of Congo. This study assesses the sustainability of artisanal mining there, finding much higher levels of cobalt in blood and urine of community members and especially of children.

Designing interventions to address water scarcity under climate change is challenging given the large uncertainties in projected water availability. In this study, changes in the uncertainty range of anticipated water scarcity conditions are identified, and a general decision-making framework to support policy decisions is developed.

Footprint analysis of how much water is embedded in food consumption in France, Germany and the United Kingdom finds geographical differences in water footprints and projects how different diets could affect water conservation.

An econometric modelling analysis shows that eliminating tariffs in key inputs for renewable energy production can have a significant impact on reducing carbon emissions in Europe.

In response to continuing habitat and biodiversity loss, leading conservationists have proposed setting aside half the earth for nature. This study evaluates the trade-offs with food production and finds losses in croplands, pasture and calories that vary with the conservation strategy.

Poaching undermines the effectiveness of marine protected areas, where enforcement capacity is limited. In this study, fishers adjacent to MPAs were surveyed, and it was found that about half had observed poaching, but that most do not react so as to avoid conflict, or because they feel that this is either not their responsibility or that poaching is a survival strategy.

Cognitive mapping reveals how people think about complex systems and enables hypothesis tests on understanding interdependency. This study finds that education and experience are associated with more nuanced form of complex-systems thinking in sustainable agriculture, such as feedback loops and indirect effects.

Intensifying agricultural production often imposes environmental costs. This study assesses progress towards the redesign of agricultural systems, finding that seven types of sustainable intensification now characterize an estimated 29% of farms on 9% of agricultural land worldwide.

Most nutrients in human excreta, if recovered, could offset substantial quantities of synthetic fertilizer use globally and advance food security goals by enhancing circular economies. This study analyses co-location of urban nutrients with nearby agricultural needs in 56 of the world’s largest cities and finds that in locations with high cropland density, nutrient-intensive crops and compact urban area, it would be possible and convenient to reuse human-derived nutrients in agriculture.

The implementation of technologic solutions to complex problems can have unintended effects. This study questions the water sustainability of using shade balls in the Los Angeles reservoir to reduce evaporation during the recent drought in California, by assessing the shade balls’ water footprint.