Explore the vast range of titles available.

Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.

Lithium-ion batteries are pivotal in climate change mitigation. While their own carbon footprint raises concerns, existing studies are scattered, hard to compare and largely overlook the relevance of battery materials. Here, we go beyond traditional carbon footprint analysis and develop a cost-based approach, estimating emission curves for battery materials lithium, nickel and cobalt, based on mining cost data. Combining the emission curves with regionalised battery production announcements, we present carbon footprint distributions (5 th , 50 th , and 95 th percentiles) for lithium-ion batteries with nickel-manganese-cobalt (NMC811, 8-1-1 ratio; 59, 74 and 115 kg CO2 kWh −1 ) and lithium-iron-phosphate (LFP; 54, 62, 69 kg CO2 kWh −1 ) cathodes. Our findings reveal the dominating impact of material sourcing over production location, with nickel and lithium identified as major contributors to the carbon footprint and its variance. This research moves the field forward by offering a nuanced understanding of battery carbon footprints, aiding in the design of decarbonisation policies and strategies. A cost-based method to assess lithium-ion battery carbon footprints was developed, finding that sourcing nickel and lithium influences emissions more than production location. This aids in designing green industrial policy.

Many studies have attempted to evaluate the transgression of the water planetary boundary at sub-global levels. Typically, this has been done by assessing water consumption in a country/city or sector against the assigned share of the global limit. Such an approach enables evaluating whether a sub-global unit operates within the safe global limits. However, it ignores spatial water availability and thus may provide an incomplete image of water-related environmental impacts and thus local boundaries. This study demonstrates how the water planetary boundary concept can be integrated within the Environmentally Extended Multi-Region Input-Output (EEMRIO) framework to assess global and local (watershed level) boundaries. Our results demonstrate that even though most countries operate within globally safe limits, for several countries, a large share of water comes from watersheds that have reached unsafe water consumption levels. This highlights the importance of combining local and global level assessments to design more accurate and tailored policy responses targeting specific watersheds that are most at risk.

Climate change and particulate matter air pollution present major threats to human well-being by causing impacts on human health. Both are connected to key air pollutants such as carbon dioxide (CO 2 ), primary fine particulate matter (PM 2.5 ), sulfur dioxide (SO 2 ), nitrogen oxides (NO x ) and ammonia (NH 3 ), which are primarily emitted from energy-intensive industrial sectors. We present the first study to consistently link a broad range of emission measurements for these substances with site-specific technical data, emission models, and atmospheric fate and effect models to quantify health impacts caused by nearly all global fossil power plants, steel mills, oil refineries and cement plants. The resulting health impact patterns differ substantially from far less detailed earlier studies due to the high resolution of included data, highlighting in particular the key role of emission abatement at individual coal-consuming industrial sites in densely populated areas of Asia (Northern and North-Eastern India, Java in Indonesia, Eastern China), Western Europe (Germany, Belgium, Netherlands) as well as in the US. Of greatest health concern are the high SO 2 emissions in India, which stand out due to missing flue gas treatment and cause a particularly high share of local health impacts despite a limited number of emission sites. At the same time, the massive infrastructure and export capacity build-up in China in recent years is taking a substantial toll on regional and global health and requires more stringent regulation than in the rest of the world due to unfavorable environmental conditions and high population densities. The current phase-out of highly emitting industries in Europe is found not to have started with sites having the greatest health impacts. Our detailed site-specific emission and impact inventory is able to highlight more effective alternatives and to track future progress.

Water scarcity adversely affects ecosystems, human well-being and the economy. It can be described by water scarcity indices (WSIs) which we calculated globally for the decades 1981-1990 and 2001-2010. Based on a model ensemble, we calculated the WSI for both decades including uncertainties. While there is a slight tendency of increased water scarcity in 2001-2010, the likelihood of the increase is rather low (53%). Climate change played only a minor role, but increased water consumption is more decisive. In the last decade, a large share of the global population already lived under highly water scarce conditions with a global average monthly WSI of 0.51 (on a scale from 0 to 1). Considering that globally there are enough water resources to satisfy all our needs, this highlights the need for regional optimization of water consumption. In addition, crop choices within a food group can help reduce humanity's water scarcity footprint without reducing its nutritional value.

Transparency in global value chains of materials, fuels, and food is critical for the implementation of sustainability policies. Such policies should be led by the G20, who represent more than 80% of global material, fuel, and food consumption. Multi-regional input–output analysis plays an important role for consumption-based assessment, including supply chains and their environmental impacts. However, previous accounting schemes were unable to fully assess the impacts of materials, fuels, and food. To close this gap, we provide an improved method to map key aspects of sustainability along value chains of materials, fuels, and food. The results show that the rise in global coal-related greenhouse gas (GHG) emissions between 1995 and 2015 was driven by the G20’s metals and construction materials industry. In 2015, the G20 accounted for 96% of global coal-related GHG emissions, of which almost half was from the extraction and processing of metals and construction materials in China and India. Major drivers include China’s rising infrastructure and exports of metals embodied in machinery, transport, and electronics consumed by other G20 members. In 2015, the vast majority (70%–95%) of the GHG emissions of metals consumed by the EU, USA, Canada, Australia, and other G20 members were emitted abroad, mostly in China. In contrast, hotspots in the impact displacement of water stress, land-use related biodiversity loss, and low-paid workforce involve the G20’s food imports from non-G20 members. Particularly high-income members have contributed to the G20’s rising environmental footprints by their increasing demand for materials, food, and fuels extracted and processed in lower-income regions with less strict environmental policies, higher water stress, and more biodiversity loss. Our results underline the G20’s importance of switching to renewable energy, substituting high-impact materials, improving supply chains, and using site-specific competitive advantages to reduce impacts on water and ecosystems.

This paper focuses on regional integration through the lenses of the Water–Food–Energy (WEF) nexus, a concept putting strong emphasis on cross-sectoral and multi-level interactions as well as on resource interdependencies. There is an extensive amount of published research focusing on the Aral Sea basin. In this paper, the authors build upon these different contributions and provide a meta-analysis of the literature of WEF nexus opportunities in Central Asia (CA) countries. This paper contributes to ongoing discussions regarding how the WEF Nexus can represent an opportunity for reinforced collaboration regarding resources management. To do so, focusing on existing literature, this paper first (1) explores how the nexus can be a relevant instrument for regional integration. Second (2), it provides an overview of water, food, energy conditions and challenges in the Aral Sea basin in particular. Third (3), synthesizing existing research, the authors identify critical variables to be considered as hurdles or leverage points for WEF nexus implementation in the Aral Sea basin. Finally (4), we go back to our initial set of questions and identify some possible avenues for future research.

The bioeconomy is key to meeting climate targets. Here, we examine greenhouse gas emissions in the global bioeconomy supply chain (1995–2022) using advanced multi-regional input-output analysis and a global land-use change model. Considering agriculture, forestry, land use, and energy, we assess the carbon footprint of biomass production and examine its end-use by provisioning systems. The footprint increased by 3.3 Gt CO 2 -eq, with 80% driven by international trade, mainly beef and biochemicals (biofuels, bioplastics, rubber). Biochemicals showed the largest relative increase, doubling due to tropical land-use change (feedstock cultivation) and China’s energy-intensive processing. Food from retail contributes most to the total biomass carbon footprint, while food from restaurants and canteens account for >50% of carbon-footprint growth, with three times higher carbon intensity than retail. Our findings emphasize the need for sustainable sourcing strategies and that adopting renewables and halting land-use change could reduce the bioeconomy carbon footprint by almost 60%. Greenhouse gas emissions from biomass production and supply are increasing, mostly driven by international trade and with the greatest relative increase from biochemical industry, according to supply chain analysis of the bioeconomy.

Purpose In this paper, we summarize the discussion and present the findings of an expert group effort under the umbrella of the United Nations Environment Programme (UNEP)/Society of Environmental Toxicology and Chemistry (SETAC) Life Cycle Initiative proposing natural resources as an Area of Protection (AoP) in Life Cycle Impact Assessment (LCIA). Methods As a first step, natural resources have been defined for the LCA context with reference to the overall UNEP/SETAC Life Cycle Impact Assessment (LCIA) framework. Second, existing LCIA methods have been reviewed and discussed. The reviewed methods have been evaluated according to the considered type of natural resources and their underlying principles followed (use-to-availability ratios, backup technology approaches, or thermodynamic accounting methods). Results and discussion There is currently no single LCIA method available that addresses impacts for all natural resource categories, nor do existing methods and models addressing different natural resource categories do so in a consistent way across categories. Exceptions are exergy and solar energy-related methods, which cover the widest range of resource categories. However, these methods do not link exergy consumption to changes in availability or provisioning capacity of a specific natural resource (e.g., mineral, water, land etc.). So far, there is no agreement in the scientific community on the most relevant type of future resource indicators (depletion, increased energy use or cost due to resource extraction, etc.). To address this challenge, a framework based on the concept of stock/fund/flow resources is proposed to identify, across natural resource categories, whether depletion/dissipation (of stocks and funds) or competition (for flows) is the main relevant aspect. Conclusions An LCIA method—or a set of methods—that consistently address all natural resource categories is needed in order to avoid burden shifting from the impact associated with one resource to the impact associated with another resource. This paper is an important basis for a step forward in the direction of consistently integrating the various natural resources as an Area of Protection into LCA.