BACKGROUND:Health is an essential component of climate adaptation and should be integrated into national policies to build resilient and effective systems. We aimed to review national climate adaptation policies to assess health integration globally, regionally, nationally, and sub-nationally. METHODS:In this global policy analysis, we systematically identified national climate adaptation policies for 198 countries in English and 14 other languages. We reviewed Health National Adaptation Plans (HNAPs), National Adaptation Plans (NAPs) or National Adaptation Programmes of Action (NAPAs) when NAPs did not exist, Nationally Determined Contributions (NDCs), and National Communications (NCs). We created a Python application to increase the accuracy of identification of health-related text and applied a standardised scoring metric that assessed five domains-health analysis, health-related actions, planned institutional leads, dedicated budgets and funding mechanisms, and measurement indicators for monitoring and evaluation (M&E)-to compare health integration across documents and countries. FINDINGS:197 countries, all except Libya, were found to have national climate adaptation policies (36 HNAPs, 123 NAPs or NAPAs, 200 NDCs, and 223 NCs). Across these policies, 458 (88% of 522 policies) mentioned health. 159 (81% of 197 countries) further referenced other national health policies. 191 (97%) identified populations disproportionately affected by climate change, whereas only 24 (12%) involved such populations in decision making. Six (3%) countries outlined budgets for health-related actions. Insufficient budgeting and fiscal planning emerged as the weakest aspects of health integration, and sexual and reproductive health and rights, allergies, injuries, violence, and mental health were found to be under-represented in policies. INTERPRETATION:Climate adaptation policies should be comprehensive and outline clear structures to translate plans into action. We need evidence-based inclusion of diseases and health conditions linked to concrete strategies, national and sub-national measurement to track progress, and designated leads to spearhead coordination. Involvement of disproportionately affected groups further bolsters policy relevance and equity, and adequate financing is central to ensuring implementation. FUNDING:None.
BACKGROUND:In river-dependent regions such as the Brazilian Amazon, severe droughts can disrupt care continuity by isolating municipalities and fragmenting supply chains. We assessed how four major droughts affected tuberculosis and HIV care cascades in Amazonas state. METHODS:We analysed monthly data (Jan 1, 2001, to Dec 31, 2024) from all 62 municipalities of the Amazonas state, Brazil, grouped into nine river basins and stratified by sex when available. Droughts were defined by the relative maximum cumulative water deficit value being below -2·0 or river discharge at or below the fifth historical percentile. We prespecified four major drought episodes affecting Amazonas at a monthly resolution: May to June, 2005; May to June, 2010; August, 2015, to April, 2016; and October, 2023, to February, 2024. Outcomes were primary-care consultations, tuberculosis and HIV notifications, treatment interruption, and disease-specific mortality. Additionally, we did a prespecified subgroup analysis stratified by sex for both diseases' indicators to assess whether drought-associated deviations differed systematically between men and women. We fitted Bayesian hierarchical negative binomial models to estimate counterfactual trajectories and summarised effects as incidence rate ratios (IRRs) and excess events per 100 000 population. FINDINGS:The 2015-16 drought coincided with widespread consultation deficits (statewide peak IRR 0·78 [95% credible interval 0·68-0·89]) and pronounced increases in HIV treatment interruption across all basins (statewide peak IRR 6·01 [2·12-15·33]), particularly among men (Rio Negro peak IRR 5·57 [3·02-9·78]). By contrast, the 2023-24 drought coincided with increased care consultations statewide (peak IRR 1·63 [1·25-2·11]) but persistent treatment interruption and mortality signals, including female-predominant increases in HIV treatment interruption in Rio Negro (peak IRR 2·87 [1·27-5·63]) and female mortality statewide (1·97 [1·05-3·39]), with additional basin-level mortality increases in Alto Solimões, Baixo Amazonas, and Médio Amazonas. Tuberculosis notifications increased mainly in 2023-24 in specific basins, especially in Baixo Amazonas (peak IRR 2·09 [1·54-2·76]), Médio Amazonas (1·74 [1·30-2·28]), and Baixo Solimões (1·60 [1·24-2·07]). INTERPRETATION:Severe droughts were associated with basin-specific disruptions in tuberculosis and HIV care cascades in the Brazilian Amazon, with clearer signals in adherence-dependent and downstream outcomes than in case detection. Strengthening resilience will require anticipatory, continuity-focused strategies that safeguard treatment access during climate-related transport constraints. FUNDING:Fundação de Amparo à Pesquisa do Estado do Amazonas and Brazilian National Council for Scientific and Technological Development.
BACKGROUND:The desiccation of the Great Salt Lake (UT, USA), driven by water use and diversion, has reduced water inflow and exposed vast areas of lakebed. Exposed lakebed can release airborne PM2·5, degrading air quality in surrounding communities. Previous research has established links between air pollution and mental health outcomes, but there is little research on the specific mental health effects of declining lake levels and associated dust exposure. We aimed to examine the association between Great Salt Lake water levels, PM2·5 concentration, and major depressive episodes in the surrounding population. METHODS:In this ecological study, we investigated relationships between Great Salt Lake decline, PM2·5 exposure, and mental health outcomes across all Utah counties using hydrological, atmospheric, and epidemiological datasets between 2006 and 2018. These data included in-situ lake measurements (from the US Geological Survey), PM2·5 from ground-based monitoring and reanalysis datasets (from MERRA-2 and AirNow network stations), the Social Vulnerability Index (from US Centers for Disease Control and Prevention), and records of major depressive episodes (from the Substance Abuse and Mental Health Services Administration). All datasets underwent quality control, variable preparation, and calculation of Z scores, and were harmonised both spatially and temporally. We calculated PM2·5 exceedance days based on US Environmental Protection Agency and WHO thresholds for harms, namely more than 15 μg/m3 and more than 35 μg/m3. Statistical analyses included Kruskal-Wallis tests for non-parametric group comparisons, followed by Dunn's post-hoc tests for pairwise comparisons. An ANOVA examined direct (main) and indirect (interaction) effects between factors, with F statistics measuring between-group versus within-group variance ratios. FINDINGS:Great Salt Lake shrinkage was linked to poorer air quality, with decreasing lake area (r=-0·28; p<0·0001) and volume (r=-0·31; p<0·0001) associated with more PM2·5 exceedance days. A dose-response relationship was found between depression severity and pollution exposure: individuals who had fewer high PM2·5 exceedance days had very low depression scores, whereas those exposed to more exceedance days had high and very high scores (H 28·9574; p<0·0001). This relationship showed nuanced differences across seasons (H 152·4771; p<0·0001) and age groups (H 51·8269; p<0·0001). Finally, our analysis showed a direct association between PM2·5 exceedance days and depression severity (F 12·341; p=0·0005), whereas social vulnerability acted as a significant moderator (F 6·979; p=0·0084). This interaction indicates that for a given level of PM2·5 exposure, socially vulnerable populations have a disproportionately higher prevalence of major depressive episodes. INTERPRETATION:This study found associations between PM2·5 exposure and depressive episodes are concerning and warrant further longitudinal investigations, including more precise exposure measurements. Our findings underscore the complex interconnections between environmental degradation, air quality deterioration, and population mental health. By establishing this desiccated air pollution to mental health association, our results show that preventing lakebed exposure is not only an ecological necessity but a crucial public health intervention. Public health protections should focus on proactive watershed management alongside targeted mental health support for the most affected downwind and socially vulnerable communities. FUNDING:US National Aeronautics and Space Administration.
BACKGROUND:Food security is central to global nutrition improvement and public health goals, and healthy diets represent a higher-level aspiration beyond merely avoiding hunger. Climate change poses an increasing threat to food systems by affecting crop yields and food prices. Although climate change-driven risks to hunger have been widely studied, the extent to which climate change undermines the affordability of healthy diets while accounting for socioeconomic responses and regional inequalities remains insufficiently understood. This study aimed to quantify the effects of climate change on the future affordability of healthy diets under alternative socioeconomic and climate scenarios. METHODS:We developed an integrated modelling framework that explicitly couples multimodel crop-yield projections with an integrated assessment model (Global Change Analysis Model [GCAM]). Yield responses from six global gridded crop models driven by four climate models were integrated into GCAM, allowing endogenous socioeconomic adjustments such as land-use shifts, production reallocation, and price responses to emerge under shared socioeconomic pathways (SSPs). Diet affordability was then assessed using the Food and Agriculture Organization of the UN's Cost and Affordability of a Healthy Diet framework across three socioeconomic-climate scenarios (SSP1-2.6, SSP2-4.5, and SSP3-6.0). FINDINGS:Under a high-emissions pathway (ie, SSP3-6.0), climate change was projected to render healthy diets unaffordable for a model-mean of 119 million people globally by 2100, even when CO2 fertilisation effects are included, with the upper end of the model ensemble reaching about 1·6 billion people. In contrast, climate-induced affordability losses were found to be negligible under both a low-emissions pathway (ie, SSP1-2.6; -0·3 million) and a medium-emission pathway (SSP2-4.5; +0·2 million). Under a high-emission pathway, model-mean projections indicated that diet costs could increase by up to 12% in the most affected regions by the end of the century. Under medium emissions, cost increases were projected to remain below 4%, whereas under low emissions, affordability changes were projected to be minimum across regions (within approximately 0·5%). Substantial regional disparities emerged, with the largest and most consistent affordability losses concentrated in low-income regions that contributed least to historical greenhouse gas emissions. Under SSP3-6.0, these disparities persisted particularly in regions of Africa and Asia despite projected three-to-five-fold increases in income over the century, with climate-induced disruptions to food systems increasing the number of people unable to afford a healthy diet through mid-century. INTERPRETATION:Climate change is likely to exacerbate global nutritional inequalities by disproportionately increasing the affordability risks of healthy diets in regions that have contributed least to historical greenhouse gas emissions. Under high-warming scenarios, socioeconomic development alone is insufficient to fully offset these risks, highlighting the structural vulnerability of low-income food systems to climate-driven price shocks. These findings suggest that in the absence of targeted interventions, climate change could continue to undermine progress towards equitable and health-oriented nutrition outcomes. FUNDING:Ministry of Science and Technology of the People's Republic of China; National Natural Science Foundation of China; National Aeronautics and Space Administration Goddard Institute for Space Studies Climate Impacts Group; Future of Life Institute; and Global Alliance for Improved Nutrition.
