Meeting the Paris Agreement's temperature goals requires limiting future carbon emissions, yet current policies make temporarily overshooting the 1.5°C target likely. The potential climate feedback from destabilizing peatlands, storing large amounts of carbon, remains poorly quantified. Using the reduced-complexity Earth System Model OSCAR with an integrated peat carbon module, we found that across various overshoot pathways that temporarily exceed 1.5°C-2.5°C, northern peatlands exhibit net positive feedback, amplifying the overshoot challenge. Warming increases peatlands' net carbon uptake, but this is largely offset by higher methane emissions. We estimated that for each 1°C increase in peak warming, the positive feedback from peatlands decreases the remaining carbon budget by 37 GtCO (22-48 GtCO). If the 1.5°C temperature target is exceeded, peatlands would increase carbon removal requirement by about 40 GtCO (16-60 GtCO) (8.6%). Our findings highlight the importance of properly accounting for northern peatlands for estimating climate feedbacks, especially under overshoot scenarios.

The years 2023 and 2024 were characterized by unprecedented warming across the globe, underscoring the urgency of climate action. Robust science advice for decision makers on subjects as complex as climate change requires deep cross- and interdisciplinary understanding. However, navigating the ever-expanding and diverse peer-reviewed literature on climate change is enormously challenging for individual researchers. We elicited expert input through an online questionnaire (188 respondents from 45 countries) and prioritized 10 key advances in climate-change research with high policy relevance. The insights span a wide range of areas, from changes in methane and aerosol emissions to the factors shaping citizens' acceptance of climate policies. This synthesis and communications effort forms the basis for a science-policy report distributed to party delegations ahead of the 29th session of the Conference of the Parties (COP29) to inform their positions and arguments on critical issues, including heat-adaptation planning, comprehensive mitigation strategies, and strengthened governance in energy-transition minerals value chains.

The Inflation Reduction Act (IRA), together with other US federal policies, offers a unique window of opportunity to promote health and equity goals through clean energy investments. Seizing these near-term opportunities to realize sizable synergies requires strategic actions from federal, state, and local actors.

In low- and middle-income countries, there is growing evidence that trees in landscapes can support healthy diets. Yet, the bulk of this evidence is based on broad-scale associations and thus fails to tease apart the contributions of different types of trees. Here, we examine how the use of on-farm trees for food, income, and fuel relates to micronutrient adequacy (vitamin A, zinc, iron, and folate) and food sourcing patterns in rural Malawi. We used data from socioeconomic, land use, and dietary surveys conducted with 460 women in both the dry and wet seasons. Our results illustrate that, compared to other uses, the use of on-farm trees for food is the most significant determinant of women's micronutrient adequacy across seasons. While this study does not find consistent dietary benefits from using on-farm trees for only fuel and income, our results suggest that multipurpose on-farm trees can support adequate intake of all measured micronutrients.

The western United States is home to most of the nation's oil and gas production and, increasingly, wildfires. We examined historical threats of wildfires for oil and gas wells, the extent to which wildfires are projected to threaten wells as climate change progresses, and exposure of human populations to these wells. From 1984-2019, we found that cumulatively 102,882 wells were located in wildfire burn areas, and 348,853 people were exposed (resided ≤ 1 km). During this period, we observed a five-fold increase in the number of wells in wildfire burn areas and a doubling of the population within 1 km of these wells. These trends are projected to increase by late century, likely threatening human health. Approximately 2.9 million people reside within 1 km of wells in areas with high wildfire risk, and Asian, Black, Hispanic, and Native American people have disproportionately high exposure to wildfire-threatened wells.

China's carbon-neutral target could have benefits for ambient fine particulate matter (PM)-associated mortality. Although previous studies have researched such benefits, the potential impact on cardiovascular disease incidence burden is yet to be investigated thoroughly. Here, we first estimate the association between short-term PM exposure and the incidence of stroke and coronary heart disease (CHD) via a case-crossover study before projecting future changes in short-term PM-associated excess incidence across China from 2025 to 2060 under three different emission scenarios. We find that, compared to the 2015-2020 baseline, average PM concentrations nationwide in 2060 under SSP119 (an approximation of a carbon-neutral scenario) are projected to decrease by 81.07%. The short-term PM-related excess incidence of stroke and CHD is projected to be reduced to 3,352 cases (95% confidence interval: 939, 5,738)-compared with 34,485 cases under a medium-emissions scenario (SSP245)-and is expected to be accompanied by a 95% reduction in the related economic burden. China's carbon-neutral policies are likely to bring health benefits for cardiovascular disease by reducing short-term PM-related incidence burden.

Short-term exposure to ground-level ozone in cities is associated with increased mortality and is expected to worsen with climate and emission changes. However, no study has yet comprehensively assessed future ozone-related acute mortality across diverse geographic areas, various climate scenarios, and using CMIP6 multi-model ensembles, limiting our knowledge on future changes in global ozone-related acute mortality and our ability to design targeted health policies. Here, we combine CMIP6 simulations and epidemiological data from 406 cities in 20 countries or regions. We find that ozone-related deaths in 406 cities will increase by 45 to 6,200 deaths/year between 2010 and 2014 and between 2050 and 2054, with attributable fractions increasing in all climate scenarios (from 0.17% to 0.22% total deaths), except the single scenario consistent with the Paris Climate Agreement (declines from 0.17% to 0.15% total deaths). These findings stress the need for more stringent air quality regulations, as current standards in many countries are inadequate.

Food systems have been identified as significant contributors to the global environmental emergency. However, there is no universally agreed-upon definition of what constitutes a planetary healthy, sustainable diet. In our study, we investigated the association between the EAT-Lancet reference diet, a diet within the planetary boundaries, and incident cancer, incident major cardiovascular events, and all-cause mortality. Higher adherence to the EAT-Lancet reference diet was associated with lower incident cancer risk (hazard ratio [HR]: 0.99; 95% confidence interval [CI]: 0.98-0.99]) and lower all-cause mortality (HR : 0.98; 95% CI: 0.98-0.99), while mostly null associations were detected for major cardiovascular event risk (HR : 1.00; 95% CI: 0.98-1.01). Stratified analyses using potentially modifiable risk factors led to similar results. Our findings, in conjunction with the existing literature, support that adoption of the EAT-Lancet reference diet could have a benefit for the prevention of non-communicable diseases.

Childhood anemia constitutes a global public health problem, especially in low- and middle-income countries (LMICs). However, it remains unknown whether global warming has an impact on childhood anemia. Here, we examined the association between annual temperatures and childhood anemia prevalence in sub-Saharan Africa and then projected childhood anemia burden attributable to climate change. Each 1°C increment in annual temperature was associated with increased odds of childhood anemia (odd ratio = 1.138, 95% confidence interval: 1.134-1.142). Compared with the baseline period (1985-2014), the attributable childhood anemia cases would increase by 7,597 per 100,000 person-years under a high-emission scenario in the 2090s, which would be almost 2-fold and over 3-fold more than those projected in moderate- and low-emission scenarios. Our results reveal the vulnerabilities and inequalities of children for the excess burden of anemia due to climate warming and highlight the importance of climate mitigation and adaptation strategies in LMICs.

As countries take stock of progress made in accomplishing their climate goals ahead of COP28 this year, it is increasingly apparent that countries must ratchet ambition in policy areas such as non-CO gases and carbon dioxide removal, while halting deforestation to lead the globe on a path consistent with the goals of the Paris Agreement.

Access to a clean and healthy environment is a human right and a prerequisite for maintaining a sustainable ecosystem. Experts across domains along the chemical life cycle have traditionally operated in isolation, leading to limited connectivity between upstream chemical innovation to downstream development of water-treatment technologies. This fragmented and historically reactive approach to managing emerging contaminants has resulted in significant externalized societal costs. Herein, we propose an integrated data-driven framework to foster proactive action across domains to effectively address chemical water pollution. By implementing this integrated framework, it will not only enhance the capabilities of experts in their respective fields but also create opportunities for novel approaches that yield co-benefits across multiple domains. To successfully operationalize the integrated framework, several concerted efforts are warranted, including adopting open and FAIR (findable, accessible, interoperable, and reusable) data practices, developing common knowledge bases/platforms, and staying vigilant against new substance "properties" of concern.

Cooling homes with air conditioners is a vital adaptation approach, but the wider adoption of air conditioners can increase hydrofluorocarbon emissions that have high global warming potential and carbon emissions as a result of more fossil energy consumption. The scale and scope of future cooling demand worldwide are, however, uncertain because the extent and drivers of air-conditioning adoption remain unclear. Here, using 2021 and 2022 Facebook and Instagram data from 113 countries, we investigate the usability of social media advertising data to address these data gaps in relation to the drivers of air-conditioning adoption. We find that social media data might represent air-conditioning purchasing trends. Globally, parents of small children and middle-aged, highly educated married or cohabiting males tend to express greater interest in air-conditioning adoption. In regions with high heat vulnerability yet little empirical data on cooling demand (e.g., the Middle East and North Africa), these sociodemographic factors play a more prominent role. These findings can strengthen our understanding of future cooling demand for more sustainable cooling management.

Current climate pledges are insufficient to achieve the aspirational goal of limiting global warming to 1.5°C. Here we discuss the critical role that non-CO greenhouse gas emissions might play in global climate change stabilization, and challenges and opportunities to pivot research and policy focus towards accelerated reductions of non-CO gases.

Plastic pollution has caused significant environmental and health challenges. Corporations that contribute to the make, use, and distribution of plastics can play a vital role in addressing global plastic pollution and many are committing to voluntary pledges. However, the extent to which corporation voluntary commitments are helping solve the problem remains underexplored. Here we develop a novel typology to characterize voluntary commitments to reduce plastic pollution made between 2015-2020 by 974 companies including the top 300 of the Fortune Global. We find that 72% of these companies have made commitments to reduce plastic pollution. About 67% of companies participating in voluntary environmental programs (VEPs) and 17% of non-VEPs participants made measurable and timebound commitments. However, rather than tackle virgin plastics, most companies target general plastics and frequently emphasize end-of-life controls with a primary focus on recycling. Growing commitments on plastic pollution are made by large and important companies, but significantly more efforts beyond plastic recycling are required to effectively address plastic pollution challenges.

Synthetic chemicals and biologically engineered materials are major forces in today's food systems, but they are also major drivers of the global environmental changes and health challenges that characterize the Anthropocene. To address these challenges, we will need to increase assessment activity, promote alternative production practices with less reliance on such technologies, and regulate social campaigns and experiments.

The use of digital tracking of individuals throughout the coronavirus 2019 (COVID-19) pandemic renewed societal debates on the efficacy and ethics of digital surveillance to mitigate collective crises. While digital emissions tracking is being used to support climate-mitigation strategies, to date there has been limited exploration of the opportunities and challenges of deploying it at the individual level. Here, we assess temporal and regional differences in levels of support for the use of digital surveillance in times of crisis, such as climate change. Results from a global survey indicate moderate support for the use of digital tracking, including for personal carbon footprints. Response varied regionally, with the lowest support in North America and Europe. This study raises key questions-if digital surveillance tools could be part of a socially acceptable response to the climate crisis, is it worth exploring? Or is this an unacceptable risk for society?

To meet the Paris temperature targets and recover from the effects of the pandemic, many countries have launched economic recovery plans, including specific elements to promote clean energy technologies and green jobs. However, how to successfully manage investment portfolios of green recovery packages to optimize both climate mitigation and employment benefits remains unclear. Here, we use three energy-economic models, combined with a portfolio analysis approach, to find optimal low-carbon technology subsidy combinations in six major emitting regions: Canada, China, the European Union (EU), India, Japan, and the United States (US). We find that, although numerical estimates differ given different model structures, results consistently show that a >50% investment in solar photovoltaics is more likely to enable CO emissions reduction and green jobs, particularly in the EU and China. Our study illustrates the importance of strategically managing investment portfolios in recovery packages to enable optimal outcomes and foster a post-pandemic green economy.

Extreme events, such as those caused by climate change, economic or geopolitical shocks, and pest or disease epidemics, threaten global food security. The complexity of causation, as well as the myriad ways that an event, or a sequence of events, creates cascading and systemic impacts, poses significant challenges to food systems research and policy alike. To identify priority food security risks and research opportunities, we asked experts from a range of fields and geographies to describe key threats to global food security over the next two decades and to suggest key research questions and gaps on this topic. Here, we present a prioritization of threats to global food security from extreme events, as well as emerging research questions that highlight the conceptual and practical challenges that exist in designing, adopting, and governing resilient food systems. We hope that these findings help in directing research funding and resources toward food system transformations needed to help society tackle major food system risks and food insecurity under extreme events.

Wicked problems such as climate change and the COVID-19 pandemic require authentically transdisciplinary approaches to achieving effective collaboration. There exist several research approaches for identifying the components and interactions of complex problems; however, collaborative autoethnography provides an empirical way to collect and analyze self-reflection that leads to transformative change. Here, we present a case study of collaborative autoethnography, applied as a tool to transform research practice among a group of natural and social scientists, by constructively revealing and resolving deep, often unseen, disciplinary divides. We ask, "How can natural and social scientists genuinely accept, respect, and share one another's approaches to work on the wicked problems that need to be solved?" This study demonstrates how disciplinary divisions can be successfully bridged by open-minded and committed collaborators who are prepared to recognize the academic bias they bring to their research and use this as a platform of strength.

The rapid and extensive changes in household consumption patterns during the coronavirus disease 2019 (COVID-19) pandemic can serve as a natural experiment for exploring the environmental outcomes of changing human behavior. Here, we assess the carbon footprint of household consumption in Japan during the early stages of the COVID-19 pandemic (January-May 2020), which were characterized by moderate confinement measures. The associated lifestyle changes did not have a significant effect on the overall household carbon footprint compared with 2015-2019 levels. However, there were significant trade-offs between individual consumption categories such that the carbon footprint increased for some categories (e.g., eating at home) or declined (e.g., eating out, transportation, clothing, and entertainment) or remained relatively unchanged (e.g., housing) for others. Furthermore, carbon footprint patterns between age groups were largely consistent with 2015-2019 levels. However, changes in food-related carbon footprints were visible for all age groups since March and, in some cases, since February.