A better approach is needed to assess potential impact and feasibility of proposals.

The ongoing climate change is expected to lead to a significant increase in the frequency and intensity of climate extremes. However, the impact of cold and hot temperatures on labour loss, through causing premature deaths in the future, remains largely unknown. We collected historic daily all-cause mortality data during 1986-2019 from 1066 locations in seven countries. A two-stage time-series approach was applied to estimate associations between non-optimum temperatures and the productivity-adjusted life year (PALY) loss due to premature deaths. These associations were then combined with projected daily temperatures under three climate change scenarios from 2021 to 2100 to quantify future PALY losses attributable to temperatures. Overall, we projected an increase in heat-related PALY loss and a decrease in cold-related PALY loss in the future. Under the SSP5-8.5 scenario, the heat-related PALY loss is projected to increase by 7.5% by the end of 2100 compared to the historical period (2001-2020), resulting in a net increase in excess PALY loss of 6.8%, greater than the net changes projected under the SSP3-7.0 (5.7%) and SSP1-2.6 (0.6%) scenarios. Brazil and Thailand were projected to experience an increase in excess heat-related PALY loss, while a reduction in excess cold-related PALY loss was projected to be most prominent in Thailand. The magnitude of the change in both heat- and cold-related PALY loss was largely affected by socioeconomic factors, such as GDP per capita and the deprivation level. This study provides a better understanding of the impacts of climate change on labour loss and provides evidence to inform targeted adaptation strategies and policy responses aimed at mitigating the socioeconomic impacts of climate change.

Background:Non-optimum temperatures have been linked to increased mortality, but the cause-, age-, and sex-specific impacts remain largely unclear. This study investigates the temperature-mortality relationships for nine causes of death across multiple countries/territories and explores subgroup differences by sex and age. Methods:We analysed the non-linear and lagged associations between temperature and mortality in 1117 locations from ten countries or territories (Australia, Brazil, Canada, Chile, Mexico, New Zealand, Philippines, South Korea, Taiwan, and Thailand) covering country-specific periods within 2000-2019, using a two-stage time-series design. In the first stage, a quasi-Poisson generalised linear regression with a distributed lag non-linear model was fitted to estimate the location-specific mortality risk associated with temperature. We then applied a meta-regression model in the second stage to synthesise the associations for cause-specific mortality. Stratified analyses were conducted by sex and age group, and the attributable fraction (AF) of mortality was subsequently estimated. Findings:We identified three distinct exposure-response patterns: an inverse J-shaped curve with higher risks from extreme cold for most causes, a U-shaped curve for all-cause and respiratory mortality, and a J-shaped curve for injury and external causes with greater risks at extreme heat. Significant differences in temperature-related mortality risks were observed across age and sex groups, with the direction and magnitude of these differences varying by cause of death. We estimated that 2.03 million deaths were attributable to non-optimum temperatures during the study period, corresponding to 4.38% (95% CI: 2.02, 6.59) of all-cause mortality. The highest AFs were observed for mental disorders (6.53%), nervous (6.40%), and cardiovascular causes (5.71%). For most causes of death, cold temperatures accounted for the largest proportion of mortality. However, for deaths related to infectious as well as injury and external causes, heat exposure contributed to the majority of the mortality. Interpretation:Our findings demonstrated substantial variations in temperature-related mortality by cause of death, sex, and age. This analysis highlights the need for tailored public health strategies that address the unique vulnerabilities of specific demographic groups across different causes of death, with targeted interventions to mitigate temperature-related health risks. Future work should focus on improving estimation in data-sparse subgroups and developing cause-, age-, and sex-specific projections of temperature-related health risks under future climate scenarios. Funding:The Australian Research Council, Australian National Health and Medical Research Council, VicHealth, and National Research Council of Thailand.

Heatwaves are increasing in frequency and intensity, yet their impacts on hospitalizations for mental and behavioural disorders remain insufficiently quantified across countries. Here we show, using a time-stratified case-crossover analysis of 2,618,307 warm-season hospitalization records from 852 locations in Brazil, Canada, Chile and New Zealand from 2000 to 2019, that sustained extreme heat was associated with increased hospitalization risk. Heatwaves were primarily defined as periods with daily mean temperature above the location-specific 97.5th percentile for at least 4 consecutive days. Under this definition, the relative risk was 1.033 (95% confidence interval, 1.007–1.059) on the same day and 1.056 (1.011–1.103) cumulatively from the same day through the next 8 days. Associations were stronger among older adults and residents of low-population-density areas. These findings indicate that prolonged extreme heat can acutely increase mental health-related hospital demand and support targeted preparedness during severe heatwaves. In an analysis of more than 2 million hospitalizations during warm seasons in four countries, extreme and prolonged heatwaves were associated with increased risk of hospitalization for mental and behavioural disorders.

Extreme heat is intensifying under climate change, yet evidence on regional and temporal variation in heat-related morbidity remains limited. Here we analyzed over 100 million emergency department (ED) visits across five countries and territories from 2000 to 2019 using a time-stratified case-crossover design to quantify associations between summer temperature and acute healthcare demand. Here we show that higher summer temperatures are associated with increased risks of ED visits across all study regions. At the 95th percentile of local daily maximum temperature, cumulative excess odds ratios are highest in Australia (42.1%, 95% confidence interval 38.1-46.2) and Taiwan (25.7%, 16.7-35.3), followed by Brazil (18.0%, 17.6-18.4), New Zealand (16.6%, 13.5-19.7), and Canada (6.1%, 4.1-8.1). Over time, heat-related risks declined in Australia but increased in Brazil. These findings reveal substantial regional and temporal heterogeneity in vulnerability and underscore the need for locally tailored heat-health adaptation strategies under a warming climate.

Adolescents are the future leaders of our world. Ensuring their health and wellbeing-now and in the future-is one of the strongest mechanisms available to safeguard the collective future of humanity and to secure a more just society and a healthier and more productive planet. Investments in the current generation of 10-24-year-olds will reap a triple dividend, with benefits for young people today, the adults they will become, and the next generation of children they will parent. These potential benefits are particularly relevant for Africa and Asia, where around 82% of the world's adolescents currently live, a proportion that is projected to rise to 85% by 2100.

Evaluating the short-term exposure to wildfire-specific fine particulate matter (PM2.5) showed greater risks of hospitalization for all major respiratory diseases than non-wildfire PM2.5. When developing air quality guidelines, it is also important to consider that PM2.5 from varying sources can have different health effects, which require targeted health and environmental policy approaches.

This secondary analysis of a crossover trial examines how fan use affects body temperature, sweating, and thermal perceptions among older adults in extreme heat.

The MJA-Lancet Countdown on health and climate change in Australia was established in 2017 and produced its first national assessment in 2018 and annual updates in 2019, 2020, 2021, 2022 and 2023. It examines five broad domains: health hazards, exposures and impacts; adaptation, planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. In this, the seventh report of the MJA-Lancet Countdown, we track progress on an extensive suite of indicators across these five domains, accessing and presenting the latest data and further refining and developing our analyses. We also examine selected indicators of trends in health and climate change in New Zealand. Our analyses show the exposure to heatwaves is growing in Australia, increasing the risk of heat stress and other health threats such as bushfires and drought. Our analyses also highlight continuing deficiencies in Australia's response to the health and climate change threat. A key component of Australia's capacity to respond to bushfires, its number of firefighting volunteers, is in decline, dropping by 38 442 people (17%) in just seven years. Australia's total energy supply remains dominated by fossil fuels (coal, oil and natural gas), and although energy from coal decreased from 2021 to 2023, energy from oil increased, and transport energy from petrol grew substantially in 2021-22 (the most recent year for which data are available). Greenhouse gas emissions from Australia's health care sector in 2021 rose to their highest level since 2010. In other areas some progress is being made. The Australian Government completed the first pass of the National Climate Risk Assessment, which included health and social support as one of the eleven priority risks, based in part on the assessed severity of impact. Renewable sources such as wind and solar now provide almost 40% of Australia's electricity, with growth in both large-scale and small-scale (eg, household) renewable generation and battery storage systems. The sale of electric vehicles reached an all-time high in 2023 of 98 436, accounting for 8.47% of all new vehicle sales. Although Australia had a reprieve from major catastrophic climate events in 2023, New Zealand experienced cyclone Gabrielle and unprecedented floods, which contributed to the highest displacement of people and insured economic losses over the period of our analyses (ie, since the year 2010 and 2000 respectively). Nationally, regionally and globally, the next five years are pivotal in reducing greenhouse gas emissions and transitioning energy production to renewables. Australia is now making progress in this direction. This progress must continue and accelerate, and the remaining deficiencies in Australia's response to the health and climate change threat must be addressed. There are strong signs that Australians are increasingly engaged and acting on health and climate change, and our new indicator on health and climate change litigation in Australia demonstrates the legal system is active on this issue in this country. Our 2022 and 2023 reports signalled our intentions to introduce indicators on Aboriginal and Torres Strait Islander health and climate change, and mental health and climate change in Australia. Although the development of appropriate indicators is challenging, these are key areas and we expect our reporting on them will commence in our next report.

BACKGROUND AND AIMS:Cardiovascular disease (CVD), the leading cause of death globally and in Australia, is sensitive to heat exposure. This study assesses the burden of CVD attributable to high temperatures across Australia and projects future burden in the context of climate change. METHODS:Disability-adjusted life years for CVD, including years of life lost and years lived with disability, were sourced from the Australian Burden of Disease database. A meta-regression model was constructed using location-specific predictors and relative risks from prior literature to estimate relative risks of CVD mortality and morbidity due to high temperatures in the Australian context. The baseline CVD burden attributable to high temperatures in Australia for 2003-18 was calculated, and future burdens under two greenhouse gas emissions scenarios [Representative Concentration Pathways (RCP4.5 and RCP8.5)] for the 2030s and 2050s were projected, considering demographic changes and human adaptation. RESULTS:During the baseline period, high temperatures accounted for 7.3% (95% confidence interval: 7.0%-7.6%) of the CVD burden in Australia, equivalent to 223.8 Disability-adjusted life years (95% confidence interval: 221.0-226.6) per 100 000 population. Future projections suggest a steady increase in the CVD burden across all scenarios examined. By the 2050s, under the RCP8.5 scenario that considers population growth and no adaptation, the total attributable burden of CVD is projected to more than double compared with the baseline, with the Northern Territory facing the most significant increase. These impacts could be mitigated with effective human adaptation to the warming climate. CONCLUSIONS:Higher temperatures are expected to exacerbate the burden of CVD. This study highlights the need for urgent adaptation and mitigation efforts to minimize the negative health impacts of a warming climate on CVD.

Transdisciplinary research has been increasingly advocated as necessary to address complex planetary health challenges spanning environmental and human health in different socio-economic contexts. Recognising global interdependence, such research must engage in equitable co-production for lasting, meaningful impact. Existing transdisciplinarity frameworks and practices from the environment, health, and development fields primarily focus on research processes and outcomes, generically mentioning ‘collaboration’ without sufficiently expanding how the process can be designed to facilitate equitable and sustained outcomes. This case study undertakes an empirical deep-dive into a planetary health research in Indonesia to better understand transdisciplinary collaboration from participants' experiences. Deductive and inductive analyses of the enabling and constraining factors offer novel insights into the collaborative process of stakeholder engagement, interaction, and integration. Rich examples from the case study were then synthesised into process design strategies to overcome structural constraints through boundary spanning, adaptive project management, and creating spaces for social learning and reflexivity. (150 words).

Under a warming climate, wildfires are becoming more frequent and severe. Multicountry studies evaluating associations between wildfire fine particulate matter (PM2.5) and respiratory hospitalizations are lacking. Here we evaluate the short-term effects of wildfire-specific PM2.5 on respiratory hospitalizations from 1,052 communities across Australia, Brazil, Canada, Chile, New Zealand, Vietnam, Thailand and Taiwan, during 2000-2019. A 1 mu g m-3 increase in wildfire-specific PM2.5 was associated with increased hospitalization risks for all-cause respiratory, asthma, chronic obstructive pulmonary disease, acute upper respiratory infection, influenza and pneumonia by 0.36%, 0.48%, 0.38%, 0.42%, 0.79% and 0.36%, respectively. Higher risks were observed among populations <= 19 or >= 60 years old, from low-income or high non-wildfire PM2.5 communities, and residing in Brazil, Thailand, Taiwan and Vietnam. Australia and New Zealand exhibited a greater hospitalization risk for asthma associated with wildfire-specific PM2.5. Compared with non-wildfire PM2.5, wildfire-specific PM2.5 posed greater hospitalization risks for all respiratory diseases and a greater burden of asthma. Wildfire-specific PM2.5 contributed to 42.4% of PM2.5-linked respiratory hospitalizations, dominating in Thailand. Overall, the substantial contribution of wildfire-specific PM2.5 to respiratory hospitalizations demands continued mitigation and adaptation efforts across most countries. Intervention should be prioritized for influenza, children, adolescents, the elderly and populations in low-income or high-polluted communities.

BACKGROUND:Bangladesh frequently experiences extreme heat and humidity, which threatens the health, wellbeing, and productivity of ready-made garment workers. Scalable, sustainable, and low-cost cooling strategies are urgently needed to protect this workforce in low-income and middle-income countries. Therefore, we examined the effects of building-level and personal-level cooling alternatives to air conditioning on worker heat strain in a simulated Bangladesh ready-made garment factory. METHODS:In a randomised cross over trial (ACTRN12622000457741), healthy participants (aged 18-40 years) recruited from a convenience sample of volunteers from diverse ethnic backgrounds completed six 3-h gender-specific ready-made garment work simulations (males ironed and females sewed) in a climate chamber at the University of Sydney: (1) current factory (control [CON]=40°C, 38% relative humidity); (2) CON with fan (FAN); (3) FAN with drinking water (FAN+HYD); (4) modified rooftop (ROOF=37·5°C, 38% relative humidity); (5) ROOF with fan (ROOF+FAN); and (6) air conditioning (AC=24°C, 40% relative humidity). Primary outcomes were end-trial core temperature, heart rate, and sweat loss fluid deficit. Linear mixed models with fixed effects of intervention and sex and random effects of participant were used for analysis. Pre-planned contrasts compared each intervention to CON, with Dunnett's correction for multiple testing. FINDINGS:Between March 16, 2022, and Nov 25, 2023, 42 participants (20 identifying as females, 22 as males) completed 247 trials. Compared to CON, male core temperature decreased with FAN+HYD (-0·27°C [99% CI -0·44 to -0·09]), ROOF (-0·35°C [-0·53 to -0·17]), ROOF+FAN (-0·28°C [-0·45 to -0·10]), and AC (-0·71°C [-0·89 to -0·53]), but in females, core temperature decreased only with AC (-0·42°C [-0·60 to -0·24]). Male heart rate was lower with FAN (-6 beats per minute [-12 to 0]), FAN+HYD (-13 beats per minute [-19 to -7]), ROOF (-8 beats per minute [-14 to -2]), ROOF+FAN (-11 beats per minute [-17 to -5]), and AC (-34 beats per minute [-41 to -28]), and female heart rate was lower with FAN+HYD (-7 beats per minute [-13 to 0]), ROOF (-8 beats per minute [-15 to -2]), ROOF+FAN (-10 beats per minute [-16 to -4]), and AC (-25 beats per minute [-31 to -18]). Male sweat loss fluid deficit was reduced with FAN+HYD (-704 g [-817 to -591]), ROOF (-205 g [-317 to -93]), and AC (-853 g [-966 to -741]), and in females with FAN+HYD (-439 g [-554 to -324]), ROOF (-131g [-246 to -16]), and AC (-513g [-628 to -398]). INTERPRETATION:Sustainable cooling interventions can reduce physiological heat strain under peak heat stress conditions in a typical non-airconditioned Bangladeshi ready-made garment factory. Cooling benefits were greater in males, highlighting potential gender-based workplace heat stress inequalities. FUNDING:Wellcome Trust.

The modern field of 'planetary health' was instigated in 2015 by the Rockefeller Foundation-Lancet Commission, which defined it as 'the health of human civilisation and the state of the natural systems on which it depends'. However, this view of human health in relation to natural systems is not really new at all. Rather, it is (re)emerging as the environmental impacts of human activities and their effects on the health of all life on Earth, now and in the future, become increasingly clear. A planetary health approach requires us to rethink dominant perspectives about how we feed, move, house, power and care for the world, as well as the implications for wellbeing and equity across generations and locations. This shift in understanding of our place as humans in relation to the planet is fundamental to addressing the polycrises of the 21st century. Planetary health approaches are increasingly embraced but not yet fully realised or embedded. More organisations and collaborations, in the health sector and beyond, are incorporating these ideas into their methods, plans and training, including concepts that are part of, but not synonymous with planetary health, such as one health, global health, environmental health, climate health and sustainable healthcare. Yet, we are still far from the collective cultural transformation needed to achieve the promise of planetary health as a movement that puts the health of people and the planet at the centre of all policy and action. Education and training in the Western tradition encourage 'human-centred' or 'colonial' thinking. There is much to (re)learn from First Nations peoples, and other non-Western worldviews, about the interdependence of all species and what that means for sustainable health and wellbeing. We offer proposals for how public health policymakers, researchers and practitioners, might support the transformation needed and address the conceptual, knowledge and governance challenges identified by the Rockefeller Foundation-Lancet Commission.

High-temperature exposure has important implications for mental and behavioural disorders (MBDs), which could lead to increased risks under climate change. However, knowledge gaps exist in quantifying the attributable burden. Here we assessed the burden of MBDs attributable to temperatures above the location-specific thresholds from 2003 to 2018 using disability-adjusted life years and projected future burdens under the climate scenarios representative concentration pathways RCP 4.5 and 8.5 across Australia, considering various climatic, demographic and adaptation scenarios. We show that high temperatures contributed to an annual loss of 8,458 disability-adjusted life years, representing 1.8% of total MBD burden in Australia. Our findings project a consistent upward trend in the high-temperature-attributable burden of MBDs over time. Specifically, this burden is expected to increase by 11.0-17.2% in the 2030s and by 27.5-48.9% in the 2050s compared to the baseline. Our study underscores the need for both adaptation and mitigation strategies to counteract the adverse effects of warming climate on mental health.