Changes in language used in long term climate policy can undermine their credibility and discourage climate action. Previous IPCC reports have promoted an idea of reaching ‘global net zero’ (GNZ) emissions by 2050 in order to limit global warming to 1.5 °C. In the latest IPCC Report, this language has been changed.

To understand the impact of this change, we survey COP 26 participants to test their willingness to accept a shift in long term policy goals. We find a low tolerance for a change and, indeed, there is substantial finance, business and political effort behind the idea of reaching GNZ by 2050.

This suggests that GNZ by 2050 will remain central to climate action.

Consistency in language in long term policy goals is central to building a (political) constituency in support of the Paris Agreement. Changes in language can undermine policy credibility, and stall effective mitigation action.

Recent changes in IPCC language to describe ‘global net zero’ (GNZ) as being reached in the ‘early or mid 2050s’ (AR6 WG1) could risk undermining the substantial cultural, political and financial momentum that has developed behind the interpretation – first developed by the IPCC SR 1.5 °C Report – that GNZ must be reached by 2050.

We survey COP 26 participants to test their willingness to accept a shift in policy goals and find a strong preference for a ‘stable’ long term policy target, widely interpreted as reaching ‘GNZ by 2050’, and a rejection of flexibility in long term policy targets, even as new scientific information becomes available.

‘GNZ by 2050’ is no longer a science based target, but has transitioned to a cultural and political metaphor actively used by stakeholders to guide their climate decision making. This makes ‘GNZ by 2050’ no less valid than the original scientific concept. This may stimulate further ‘political calibration’ or between the policy and modelling communities.

Sig. momentum is behind global net zero by 2050.Will changes in IPCC mitigation language de-rail global climate action?

To meet the UK's greenhouse gas (GHG) emissions targets, the Climate Change Committee (CCC) recommended to reduce current meat and dairy intake by 20% by 2030. In this study, we modelled the impact of potential dietary changes on GHG emissions and water use with the selected scenarios based on the trend of food purchase and meat and dairy reduction policy. We show that implementing fiscal measures and facilitating innovations in production of meat alternatives would accelerate existing positive trends, help the UK reach the CCC 2030 target of 20% meat and dairy reduction and increase fruit and vegetable intake.

We used 2001–2019 data from the Family Food module of the Living Costs and Food Survey (LCF), an annual UK survey of about 5,000 representative households recording quantities of all food and drink purchases, to model four 2030 dietary scenarios: Business as usual (BAU); two fiscal policy scenarios (‘fiscal 10%’ and ‘fiscal 20%’), combining either a 10% meat and dairy tax and a 10% fruit and vegetable subsidy, or a 20% tax and 20% subsidy on the same foods; and an ‘innovation scenario’ substituting traditionally-produced meat and dairy with plant-based analogues and animal proteins produced in laboratories. Compared to 2019 levels, we forecasted reductions in the range of 5–30% for meat and 8–32% for dairy across scenarios. Meat reductions could be up to 21.5% (fiscal20%) and 30.4% (innovation). For all scenarios we forecasted an increase in fruit and vegetables intake in the range of 3–13.5%; with the fiscal 20% scenario showing highest increases (13.5%). GHG emissions and water use reductions were highest for the innovation scenario (−19.8%, −16.2%) followed by fiscal 20% (−15.8%, −9.2%) fiscal 10% (−12.1%, 5.9%) and BAU (−8.3%, −2.6%) scenarios. Compared to average households, low-income households had similar patterns of change, but both past and predicted purchase of meat, fruit and vegetables and environmental footprints were lower.

Meat and dairy-reduction policies would help meet net zero targets and improve population health in the UK.

The significant outlays by countries in the Global South to recover from the COVID-19 crisis could have been an opportunity to build back better, advancing both a green recovery and addressing pressing social problems, thus advancing sustainability. To examine if this was the case, in this paper we analyze the expected impacts of recovery initiatives in five Latin American countries. Our results show that these programs do not support the possibility of building back better, weakly impacting 12 dimensions related to sustainability. We also propose a methodology to improve how sustainability concerns can be included in future choice of projects.

It has been argued that the significant outlays by governments across the world required to recover from the COVID-19 crisis can be an opportunity to build back better, that is, advance toward greener societies. In the Global South, which suffered acute social, economic and environmental problems prior to this health crisis, recovery initiatives would be best suited to focus on sustainable economic recovery which – along with the environmental concerns of a green recovery – could address pressing local problems. To this end, we analyzed the expected impacts of recovery initiatives in five Latin American countries on each of 71 sustainability criteria. These criteria are based on the UN sustainable development goals and other relevant literature related to sustainable development. Using principal component analysis, criteria are grouped into 12 dimensions. Our results show that recovery programs examined do not take advantage of the possibility of building back better, and many relevant dimensions related to a sustainable recovery are only weakly considered. Our methodology provides a step forward toward supporting governments in their efforts to identify better policies and investment projects and consequently put together packages of initiatives that advance on sustainability, green recovery or other long-term goals they may have.

Methodology to analyze COVID-19 recovery packages shows small impact on sustainability in five Latin American countries.

The industrial food system is widely considered to be unsustainable due to its undesired climate and health effects. One proposed alternative to these problems is a more local system of food provisioning. This means involving individuals, households, and communities in growing and acquiring edibles, like vegetables and other food stuff. This study based on a literature review found that food self-provisioning practitioners are mainly driven by health concerns and less by reasoning linked to the environment, like climate change adaptation and mitigation. We propose that the potential of food self-provisioning is underutilised in developing the sustainability of food systems.

In this article, we review and analyse the literature and concept of ‘food self-provisioning’ in order to understand its potential as a response to contemporary challenges. The focus of the study is on investigating the meanings related to environmental problems, particularly climate change, and issues of health. Firstly, we show how food self-provisioning is conceptualised vis-à-vis health and the environment; and secondly, what the (potential) implications of food self-provisioning to interlinked human and non-human health and beyond are. Based on the conducted literature review (n = 44), meanings of food self-provisioning are found to connect primarily to issues of human health and only secondarily to environmental questions, and even more marginally to climate change mitigation and adaptation. Our analysis cuts across the scales of households, communities, cities, and regions, including their diverse geographies, and hereby also comments on the questions of multilevel organising of self-provisioning, and what the notion of ‘self’ implies in this context.

The potential of food self-provisioning is underutilised in developing the sustainability of food systems.

The United Nations' sustainable development goals (SDGs) articulate societal aspirations for people and our planet. Many scientists have criticised the SDGs and some have suggested that a better understanding of the complex interactions between society and the environment should underpin the next global development agenda. We further this discussion through the theory of social–ecological resilience, which emphasises the ability of systems to absorb, adapt, and transform in the face of change. We determine the strengths of the current SDGs, which should form a basis for the next agenda, and identify key gaps that should be filled.

The United Nations' sustainable development goals (SDGs) are past their halfway point and the next global development agenda will soon need to be developed. While laudable, the SDGs have received strong criticism from many, and scholars have proposed that adopting complex adaptive or social–ecological system approaches would increase the effectiveness of the agenda. Here we dive deeper into these discussions to explore how the theory of social–ecological resilience could serve as a strong foundation for the next global sustainable development agenda. We identify the strengths and weaknesses of the current SDGs by determining which of the 169 targets address each of 43 factors affecting social–ecological resilience that we have compiled from the literature. The SDGs with the strongest connections to social–ecological resilience are the environment-focus goals (SDGs 2, 6, 13, 14, 15), which are also the goals consistently under-prioritised in the implementation of the current agenda. In terms of the 43 factors affecting social–ecological resilience, the SDG strengths lie in their communication, inclusive decision making, financial support, regulatory incentives, economic diversity, and transparency in governance and law. On the contrary, ecological factors of resilience are seriously lacking in the SDGs, particularly with regards to scale, cross-scale interactions, and non-stationarity.

The post-2030 agenda should build on strengths of SDGs 2, 6, 13, 14, 15, and fill gaps in scale, variability, and feedbacks.

Environmental threats to shelter, livelihoods, and food security are often considered push factors for intra-African human migration. Research in this field is often fragmented into a myriad of case studies on specific subregions or events, thus preventing a more comprehensive understanding of the phenomenon. This paper examines environmental drivers reported in the literature as push factors for human displacement across 32 sub-Saharan African countries between 1990 and 2021. Extensive consultation of past studies and reports with analytical methods shows that environmental migration is complex and influenced by multiple direct and indirect factors. Non-environmental drivers compound the effects of environmental change.

Intra-African environmental migration is a bleak reality. Warming trends, aridification, and the intensification of extreme climate events, combined with underlying non-environmental drivers, may set millions of people on the move. Despite previous studies and meta-analyses on environmental migration within sub-Saharan Africa (SSA), conclusive empirical evidence of the relationship between environmental change and migration is still missing. Here we draw on 87 case studies published in the scholarly literature (from fields ranging from the environmental sciences to development economics and migration research) or documented by research databases, reports, and international disaster datasets to develop a meta-analysis investigating the relationship between environmental changes and migration across SSA. A combination of quantitative, Qualitative Comparative Analyses (QCA), and statistical correlation methods are used to analyze the metadata and investigate the complex web of environmental drivers of environmental migration in SSA while highlighting subregional differences in the predominant environmental forcing. We develop a new conceptual framework for investigating the cascading flow of interdependences among environmental change drivers of human displacement while reconstructing the main migration patterns across SSA. We also present new insights into the way non-environmental factors are exposing communities in SSA to high vulnerability and reduced resilience to environmental change.

Human displacement in sub-Saharan Africa is often associated with the effects of climate change and environmental degradation.

Globalisation has narrowed the gap between producers and consumers. Nations are increasingly relying on commodities produced outside of their borders for satisfying their consumption. This is particularly the case for the European Union (EU). This study assesses spillover effects, i.e. impacts taking place outside of the EU borders, resulting from the EU's demand for food products, in terms of environmental and social indicators.

Human demand for agri-food products contributes to environmental degradation in the form of land-use impacts and emissions into the atmosphere. Development and implementation of suitable policy instruments to mitigate these impacts requires robust and timely statistics at sectoral, regional and global levels. In this study, we aim to assess the environmental and social impacts embodied in European Union's (EU's) demand for agri-food products. To this end, we select a range of indicators: emissions (carbon dioxide, particulate matter, sulphur dioxide, nitrous oxide), land use, employment and income. We trace these environmental and social impacts across EU's trading partners to identify specific sectors and regions as hotspots of international spillovers embodied in EU's food supply chains and find that these hotspots are wide-ranging in all continents. EU's food demand is responsible for 5% of the EU's total CO2 consumption-based footprint, 9% of the total NOX footprint, 16% of the total PM footprint, 6% of the total SO2 footprint, 46% of the total land-use footprint, 13% of the total employment footprint and 5% of the total income footprint. Our results serve to inform future reforms in the EU for aligning policies and strategies with the Sustainable Development Goals (SDGs) and the objectives of the Paris Climate Agreement.

Significant environmental and social spillover effects embodied in the EU's food supply chains.

When developing and deploying negative emissions technologies (NETs), little attention has been paid to where. On the one hand, one might develop NETs where they are likely to contribute most to global mitigation targets, contributing to a global climate solution. On the other hand, one might develop NETs where they can help support development on a regional basis, justified by regional demands. I defend these arguments and suggest that they reflect the values of efficiency and responding to need, respectively. To the extent that these values conflict, they introduce what I call the Need-Efficiency Trade-off Effect (‘NET Effect’).

Unlike other geoengineering methods, the effectiveness of negative emissions technologies (NETs) tends to be sensitive to regional siting. This paper argues that this point raises morally and legally important implications by identifying a trade-off between ‘efficiency’ and ‘need’. First, it introduces two arguments justifying NETs: one focused on contributions to global mitigation and the other focused on contributions to regional development. Second, reflecting the two arguments, the paper discusses the moral values of efficiency and need, respectively. For instance, if the strategy is to try to use NETs to maximize expected mitigation contributions to reflect efficiency, then deployment should occur in regions with the best prospects for success (e.g. Western countries). However, if the strategy is to try to use NETs to improve the chances of simultaneous development and mitigation to respond to need, then deployment should occur in regions with limited development and expected growth of demand for NETs (e.g. Asian countries). When these values conflict, I call that a Need-Efficiency Trade-off Effect (‘NET Effect’). The paper concludes by considering the NET Effect in the context of bioenergy with carbon capture and storage as well as direct air carbon capture and storage.

Should negative emissions technologies be deployed in Western countries for most climate action or Asian where needed for development?

Cities in the distant past – as documented by archaeologists and historians – provide an extensive record of urban successes and failures, yet this information has had little impact on the field of sustainability science. I explore two reasons for this situation. First, these scholars have often failed to synthesize their data scientifically, and, second, they have not approached the transfer of past knowledge to present research in a rigorous manner. I organize discussion of these issues around three arguments for the present value of past cities: the urban trajectory argument, the sample size argument, and the laboratory argument.

I explore the different ways historical and archaeological data can be deployed to contribute to research on urban sustainability science, emphasizing issues of argumentation and epistemology. I organize the discussion around three types of argument. The urban trajectory argument exploits the long time series of early cities and urban regions to examine change at a long time scale. The sample size argument views the role of early cities as adding to the known sample of settlements to increase understanding of urban similarities and differences. The laboratory argument uses data from past cities to explicitly test models derived from contemporary cities. Each argument is examined for three contrasting epistemological approaches: heuristic analogs, case studies, and quantitative studies. These approaches form a continuum leading from lesser to greater scientific rigor and from qualitative to quantitative frameworks. Much past-to-present argumentation requires inductive logic, also called reasoning by analogy. Sustainability scientists have confused this general form of argument with its weakest version, known as heuristic analogs. I stress ways to improve methods of argumentation, particularly by moving research along the continuum from weaker to stronger arguments.

Better methods of argument allow the past record of urban success and failure to contribute to urban sustainability science.

As green spaces, lawns are often thought to capture carbon from the atmosphere. However, once mowing, fertlising and irrigation are taken into account, we show that they become carbon sources, at least in the long run. Converting unused urban and rural lawn and grassland to treescapes can make a substantial contribution to reducing greenhouse gas emissions and increasing carbon absorption from the atmosphere. However, it is imperative for governing bodies to put in place appropriate policies and incentives in order to achieve this.

Mown grass or lawn is a ubiquitous form of vegetation in human-dominated landscapes and it is often claimed to perform an ecosystem service by sequestering soil carbon. If lawn maintenance is included, however, we show that lawns become net carbon emitters. We estimate that globally, if one-third of mown grass in cities was returned to treescapes, 310–1630 million tonnes of carbon could be absorbed from the atmosphere, and up to 43 tonnes of carbon equivalent per hectare of emissions could be avoided over a two-decade time span. We therefore propose that local and central governments introduce policies to incentivise and/or regulate the conversion of underutilised grass into treescapes.

If unused lawns were planted with trees, a gigaton of carbon could be removed from the atmosphere over two decades.

A widely held belief is that once the impacts of warming are experienced more directly and substantially, especially by affluent populations, the necessary support for a politics prioritising ambitious emissions reductions will follow. But consideration of the indirect socioeconomic impacts of warming suggests this could be false hope.

There is some evidence to support the common intuition that, as the direct impacts of warming intensify – particularly in the affluent Global North – a politics ambitious enough to confront the climate emergency may finally find support. However, it seems at least equally likely that the opposite trend will prevail. This proposition can be understood by considering various indirect impacts of warming, including the widening of socioeconomic inequalities (within and between countries), increases in migration (intra- and inter-nationally) and heightened risk of conflict (from violence and war through to hate speech and crime). Compiling these impacts reveals a considerable and highly inconvenient overlap with key drivers of the authoritarian populism that has proliferated in the 21st century. It highlights the risk of a socio-ecological feedback loop where the consequences of warming create a political environment entirely at odds with that required to reduce emissions. Such a future is, of course, far from inevitable. Nonetheless, the risks highlight the urgent need to find public support for combined solutions to climate change and inequality, which go well beyond the status-quo. This is necessary not only for reasons of economic and climate justice, but in order to mitigate political barriers to carbon mitigation itself.

As the impacts of warming are experienced more directly and substantially, we may vote for precisely the wrong people.

Rivers are crucial to the water cycle, linking the landscape to the sea. Human activities, including effluent discharge, water use and fisheries, have transformed the resilience of many rivers around the globe. Sustainable development goal (SDG) 14 prioritizes addressing many of the same issues in marine ecosystems. This review illustrates how rivers contribute directly and indirectly to SDG 14 outcomes, and also provides ways to potentially address them through a river to sea view on policy, management and research.

The United Nations initiated the SDGs to produce ‘a shared blueprint for peace and prosperity for people and the planet, now and into the future’. Established in 2015, progress of SDGs directed at the aquatic environment is slow despite an encroaching 2030 deadline. The modification of flow regimes combined with other anthropogenic pressures underpin ecological impacts across aquatic ecosystems. Current SDG 14 targets (life below water) do not incorporate the interrelationships of rivers and marine systems systematically, nor do they provide recommendations on how to improve existing management and policy in a comprehensive manner. Therefore, this review aims to illustrate the linkages between rivers and marine ecosystems concerning the SDG 14 targets and to illustrate land to sea-based strategies to reach sustainability goals. We provide an applied case study to show how opportunities can be explored. We review three major areas where mutual opportunities are present: (1) rivers contribute to marine and estuary ecosystem resilience (targets 14.1, 14.2, 14.3, 14.5); (2) resilient rivers are part of the global fisheries sustainability concerns (targets 14.4, 14.6, 14.7, 14.B) and (3) enhancing marine policy and research from a river and environmental flows perspective (targets 14.A, 14.C).

Restoring resilience to rivers and their environmental flows helps fulfil SDG 14.

We summarize what we assess as the past year's most important findings within climate change research: limits to adaptation, vulnerability hotspots, new threats coming from the climate–health nexus, climate (im)mobility and security, sustainable practices for land use and finance, losses and damages, inclusive societal climate decisions and ways to overcome structural barriers to accelerate mitigation and limit global warming to below 2°C.

We synthesize 10 topics within climate research where there have been significant advances or emerging scientific consensus since January 2021. The selection of these insights was based on input from an international open call with broad disciplinary scope. Findings concern: (1) new aspects of soft and hard limits to adaptation; (2) the emergence of regional vulnerability hotspots from climate impacts and human vulnerability; (3) new threats on the climate–health horizon – some involving plants and animals; (4) climate (im)mobility and the need for anticipatory action; (5) security and climate; (6) sustainable land management as a prerequisite to land-based solutions; (7) sustainable finance practices in the private sector and the need for political guidance; (8) the urgent planetary imperative for addressing losses and damages; (9) inclusive societal choices for climate-resilient development and (10) how to overcome barriers to accelerate mitigation and limit global warming to below 2°C.

Science has evidence on barriers to mitigation and how to overcome them to avoid limits to adaptation across multiple fields.

Humans have the tendency to damage the natural environment in many ways. Deforestation and conversion of forests for residential, industrial development, and expansion of agricultural crops, as well as the burning of fossil fuels, are some activities that disrupt natural ecosystems and wildlife and contribute to climate change. As a result, the life cycles of pathogens and intermediate hosts (insects, rodents, mammals) as well as biodiversity are affected. Through these activities, humans meet wild animals that transmit pathogens, resulting in their infection by zoonoses and causing epidemics–pandemics, the effects of which have as their final recipient himself and his activities.

This article aims to highlight the two-way relationship between those human activities and the occurrence of epidemics–pandemics. We will try to elaborate this two-way relationship, through the overview of the current pandemic (origin of SARS-CoV-2, modes of transmission, clinical picture of the disease of COVID-19, influence of weather and air pollution on prevalence and mortality, pandemic effects, and treatments). They are used as primary sources, scientific articles, literature, websites, and databases (Supplementary appendix) to analyze factors involved in the occurrence and transmission of zoonotic diseases in humans (Ebola, influenza, Lyme disease, dengue fever, cholera, AIDS/HIV, SARS-CoV, MERS-CoV). The present paper concluded that humanity today faces two major challenges: controlling the COVID-19 pandemic and minimizing the risk of a new global health crisis occurring in the future. The first can be achieved through equitable access to vaccines and treatments for all people. The second needs the global community to make a great change and start protecting the natural environment and its ecosystems through the adoption of prevention policies.

Two-way relationship between human activities and epidemics highlighted, through review of the COVID-19 pandemic.

Integrated assessment models (IAMs) are important scientific tools for advising policymakers and the public on climate mitigation. Recent results of modeling exercises relied upon large amounts of techniques that can capture carbon dioxide from the atmosphere, undoing current and past emissions. I argue that the reliance on such techniques unduly shifts risk to future generations and away from current high emitting countries. From an ethical point of view, this is problematic. IAM studies need to be more explicit about the value positions that evidence of mitigation pathways depends upon and should represent a wider array of plausible value positions.

This paper analyzes the nonepistemic value judgments involved in modeling Carbon Dioxide Removal (CDR) techniques. The comparably high uncertainty of these techniques gives rise to epistemic risk when large-scale CDR is relied upon in most scenario evidence. Technological assumptions on CDR are thus entangled with nonepistemic value judgments. In particular, the reliance on large-scale CDR implies shifting risk to future generations and thereby gives a one-sided answer to questions of intergenerational justice. This bias in integrated assessment modeling is problematic given the policy-advising role of integrated modeling. Modeling climate mitigation should focus on transforming these implicit value positions into explicit scenario parameters and should aim to provide scenario evidence on the complete array of value-laden mitigation strategies.

The ethics of mitigation pathways, for example in relation to CDR, must be made transparent and plural.

A substantial increase in wind energy deployment worldwide is required to help achieve international targets for decreasing global carbon emissions and limiting the impacts of climate change. In response to global concerns regarding the environmental effects of wind energy, the International Energy Agency Wind Technical Collaborative Program initiated Task 34 – Working Together to Resolve Environmental Effects of Wind Energy or WREN. As part of WREN, this study performed an international assessment with the global wind energy and environmental community to determine priority environmental issues over the next 5‒10 years and help support collaborative interactions among researchers, developers, regulators, and stakeholders.

A systematic assessment was performed using feedback from the international community to identify priority environmental issues for land-based and offshore wind energy development. Given the global nature of wind energy development, feedback was of interest from all countries where such development is underway or planned to help meet United Nations Intergovernmental Panel on Climate Change targets. The assessment prioritized environmental issues over the next 5–10 years associated with wind energy development and received a total of 294 responses from 28 countries. For land-based wind, the highest-ranked issues included turbine collision risk for volant species (birds and bats), cumulative effects on species and ecosystems, and indirect effects such as avoidance and displacement. For offshore wind, the highest-ranked issues included cumulative effects, turbine collision risk, underwater noise (e.g. marine mammals and fish), and displacement. Emerging considerations for these priorities include potential application to future technologies (e.g. larger turbines and floating turbines), new stressors and species in frontier regions, and cumulative effects for multiple projects at a regional scale. For both land-based and offshore wind, effectiveness of minimization measures (e.g. detection and deterrence technologies) and costs for monitoring, minimization, and mitigation were identified as overarching challenges.

Turbine collisions and cumulative effects among the international environmental priorities for wind energy development.

Almost 6 years have passed since the Colombian peace agreement was signed. However, the promise of a ‘Stable and lasting peace’ is slipping away as the transition towards peace is increasingly tainted and overshadowed with violence. The future of Colombia is at a crossroad and without international support and action taken to monitor global supply chains, these particular drivers of conflict, violence and environmental degradation will persist. We summarize the current situation and shed light on the complexities of building peace in Colombia, with a particular focus on the environmental changes that took place since the peace agreement was signed.

The Colombian peace agreement officially ended one of the world's longest internal armed conflicts. But the transformation of land use that takes place in the wake of the peace agreement has made the historic inequalities of access to land more visible and revealed inherent and violent struggles over resources that persist across the country. In this briefing we analyse the current status of peacebuilding in Colombia and highlight the major barriers and challenges in the current peacebuilding efforts. We show how the last few years brought severe and negative repercussions for people, communities and the natural environment in Colombia as cattle ranching, ‘productive agriculture’ and extractive industries are increasingly encroaching into indigenous territories, protected areas and forest ecosystems, replacing diverse natural forests that support biodiversity and contribute to human well-being locally and globally. The resurging presence of numerous armed groups seeking to control the profitable drug trade and mineral deposits are a major problem and obstacle for building lasting and sustainable peace among people and with the natural environment in Colombia. We conclude this briefing with points that we see as crucial to support the implementation of the peace agreement.

Colombia's peacebuilding effort must foster environmental stewardship and respect its biological and cultural diversity.

Globally, freshwater systems are degrading due to excessive water withdrawals. We estimate that if rivers’ environmental flow requirements were protected, the associated decrease in irrigation water availability would reduce global yields by ~5%. As one option to increase food supply within limited water resources, we show that dietary changes toward less livestock products could compensate for this effect. If all currently grown edible feed was directly consumed by humans, we estimate that global food supply would even increase by 19%. We thus provide evidence that dietary changes are an important strategy to harmonize river flow protection with sustained food supply.

To protect global freshwater ecosystems and restore their integrity, freshwater withdrawals could be restricted to maintain rivers' environmental flow requirements (EFRs). However, without further measures, reduced irrigation water availability would decrease crop yields and put additional pressure on global food provision. By comparing the quantitative effects of both global EFR protection and dietary changes on regional and global food supply in a spatially explicit modeling framework, we show that dietary changes toward less livestock products could effectively contribute to solving this trade-off. Results indicate that protection of EFRs would almost halve current global irrigation water withdrawals and reduce global crop yields by 5%. Limiting animal protein share to 25, 12.5 and 0% of total protein supply and shifting released crop feed to direct human consumption could however increase global food supply by 4, 11 and 19%, respectively. The effects are geographically decoupled: water-scarce regions such as the Middle East, or South and Central Asia would be most affected by EFR protection, whereas dietary changes are most effective in North America and Europe. This underpins the disproportionally high responsibilities of countries with resource-intensive diets and the need for regionally adapted and diverse strategies to transform the global food system toward sustainability.

Combining dietary changes and global river flow protection could contribute to a more sustainable food system.