OBJECTIVE: The objective of this research is to develop and implement the Change and Health Evaluation and Response System (CHEERS) as a methodological framework, designed to facilitate the generation and ongoing monitoring of climate change and health-related data within existing Health and Demographic Surveillance Sites (HDSSs) and comparable research infrastructures.

METHODS: CHEERS uses a multi-tiered approach to assess health and environmental exposures at the individual, household, and community levels, utilizing digital tools such as wearable devices, indoor temperature and humidity measurements, remotely sensed satellite data, and 3D-printed weather stations. The CHEERS framework utilizes a graph database to efficiently manage and analyze diverse data types, leveraging graph algorithms to understand the complex interplay between health and environmental exposures.

RESULTS: The Nouna CHEERS site, established in 2022, has yielded significant preliminary findings. By using remotely-sensed data, the site has been able to predict crop yield at a household level in Nouna and explore the relationships between yield, socioeconomic factors, and health outcomes. The feasibility and acceptability of wearable technology have been confirmed in rural Burkina Faso for obtaining individual-level data, despite the presence of technical challenges. The use of wearables to study the impact of extreme weather on health has shown significant effects of heat exposure on sleep and daily activity, highlighting the urgent need for interventions to mitigate adverse health consequences.

MATERIALS AND METHODS: The cross-sectional study was conducted through cloud-data-based digital questionnaires completed by randomly selected residents in the Johor River Basin (n=647). Data was analysed with descriptive statistics using SPSS 27 (IBM®) Software. Comparisons between indigenous and non-indigenous communities were performed using Chi square analysis.

RESULTS: Respondents in this study consisted of indigenous people (n=79) and non-indigenous people (n=568). Indigenous respondents generally perceived more frequent occurrence of extreme weather events in the next 20 years, even for the phenomena unfamiliar in Malaysian settings. All respondents showed similar concerns for health impacts of global warming, although the non-indigenous respondents perceived the risk further into the future (25 years) compared to the indigenous respondents who perceived current or imminent (<10 years) risks. Intense concerns for self, children, family members and community were shown by nearly all indigenous respondents (97-99%), while the non-indigenous people in this study expressed stronger concerns at country level and for future generations. During the last haze episode, most indigenous respondents (85%) did not notice any change in air quality nor discomfort among family members, in contrast 70% of the nonindigenous respondents claimed to have suffered from breathing problems themselves as well as others in the family. All respondents were concerned about air quality in their surroundings, indigenous people were concerned for the near future (<10 years), and non-indigenous people were concerned for the next 25 years.

A DEBILITATED FIRST LINE OF DEFENCE: With the worsening health impacts of climate change compounding other coexisting crises, populations worldwide increasingly rely on health systems as their first line of defence. However, just as the need for healthcare rises, health systems worldwide are debilitated by the effects of the COVID-19 pandemic and the energy and cost-of-living crises. Urgent action is therefore needed to strengthen health-system resilience and to prevent a rapidly escalating loss of lives and to prevent suffering in a changing climate. However, only 48 (51%) of 95 countries reported having assessed their climate change adaptation needs (indicator 2.1.1) and, even after the profound impacts of COVID-19, only 60 (63%) countries reported a high to very high implementation status for health emergency management in 2021 (indicator 2.2.4). The scarcity of proactive adaptation is shown in the response to extreme heat. Despite the local cooling and overall health benefits of urban greenspaces, only 277 (27%) of 1038 global urban centres were at least moderately green in 2021 (indicator 2.2.3), and the number of households with air conditioning increased by 66% from 2000 to 2020, a maladaptive response that worsens the energy crisis and further increases urban heat, air pollution, and greenhouse gas emissions. As converging crises further threaten the world’s life-supporting systems, rapid, decisive, and coherent intersectoral action is essential to protect human health from the hazards of the rapidly changing climate.

HEALTH AT THE MERCY OF FOSSIL FUELS: The year 2022 marks the 30th anniversary of the signing of the UN Framework Convention on Climate Change, in which countries agreed to prevent dangerous anthropogenic climate change and its deleterious effects on human health and welfare. However, little meaningful action has since followed. The carbon intensity of the global energy system has decreased by less than 1% since the UNFCCC was established, and global electricity generation is still dominated by fossil fuels, with renewable energy contributing to only 8·2% of the global total (indicator 3.1). Simultaneously, the total energy demand has risen by 59%, increasing energy-related emissions to a historical high in 2021. Current policies put the world on track to a catastrophic 2·7°C increase by the end of the century. Even with the commitments that countries set in the Nationally Determined Contributions (NDCs) updated up until November 2021, global emissions could be 13·7% above 2010 levels by 2030—far from the 43% decrease from current levels required to meet Paris Agreement goals and keep temperatures within the limits of adaptation. Fossil fuel dependence is not only undermining global health through increased climate change impacts, but also affects human health and wellbeing directly, through volatile and unpredictable fossil fuel markets, frail supply chains, and geopolitical conflicts. As a result, millions of people do not have access to the energy needed to keep their homes at healthy temperatures, preserve food and medication, and meet the seventh Sustainable Development Goal (to ensure access to affordable, reliable, sustainable, and modern energy for all). Without sufficient support, access to clean energy has been particularly slow in low HDI countries, and only 1·4% of their electricity came from modern renewables (mostly wind and solar power) in 2020 (indicator 3.1). An estimated 59% of healthcare facilities in low and middle-income countries still do not have access to the reliable electricity needed to provide basic care. Meanwhile, biomass accounts for as much as 31% of the energy consumed in the domestic sector globally, mostly from traditional sources—a proportion that increases to 96% in low HDI countries (indicator 3.2). The associated burden of disease is substantial, with the air in people’s homes exceeding WHO guidelines for safe concentrations of small particulate air pollution (PM2·5) in 2020 by 30-fold on average in the 62 countries assessed (indicator 3.2). After 6 years of improvement, the number of people without access to electricity increased in 2020 as a result of the socioeconomic pressures of the COVID-19 pandemic. The current energy and cost-of-living crises now threaten to reverse progress toward affordable, reliable, and sustainable energy, further undermining the socioeconomic determinants of health. Simultaneously, oil and gas companies are registering record profits, while their production strategies continue to undermine people’s lives and wellbeing. An analysis of the production strategies of 15 of the world’s largest oil and gas companies, as of February 2022, revealed they exceed their share of emissions consistent with 1·5°C of global heating (indicator 4.2.6) by 37% in 2030 and 103% in 2040, continuing to undermine efforts to deliver a low carbon, healthy, liveable future. Aggravating this situation even further, governments continue to incentivise fossil fuel production and consumption: 69 (80%) of 86 countries reviewed had net-negative carbon prices (ie, provided a net subsidy to fossil fuels) for a net total of US$400 billion in 2019, allocating amounts often comparable with or even exceeding their total health budgets (indicator 4.2.4). Simultaneously, wealthier countries failed to meet their commitment of mobilising the considerably lower sum of $100 billion annually by 2020 as agreed at the 2009 Copenhagen Accord to support climate action in “developing countries”, and climate efforts are being undercut by a profound scarcity of funding (indicator 2.1.1). The impacts of climate change on global economies, together with the recession triggered by COVID-19 and worsened by geopolitical instability, could paradoxically further reduce the willingness of countries to allocate the funds needed to enable a just climate transition.

A HEALTH-CENTRED RESPONSE FOR A THRIVING FUTURE: The world is at a critical juncture. With countries facing concurrent crises, the implementation of long-term emissions-reduction policies risks being deflected or defeated by challenges wrongly perceived as more immediate. Addressing each of the concurrent crises in isolation risks alleviating one, while worsening another. Such a situation is emerging from the response to COVID-19, which has so far has not delivered the green recovery that the health community proposed, and, on the contrary, is aggravating climate change-related health risks. Less than one third of $3·11 trillion allocated to COVID-19 economic recovery is likely to reduce greenhouse gas emissions or air pollution, with the net effect likely to increase emissions. The COVID-19 pandemic affected climate action at the city level, and 239 (30%) of 798 cities reported that COVID-19 reduced financing available for climate action (indicator 2.1.3). As countries search for alternatives to Russian oil and gas, many continue to favour the burning of fossil fuels, with some even turning back to coal. Shifts in global energy supplies threaten to increase fossil fuel production. Even if implemented as a temporary transition, these responses could reverse progress on air quality improvement, irreversibly push the world off track from meeting the commitments set out in the Paris Agreement, and guarantee a future of accelerated climate change that threatens human survival. On the contrary, in this pivotal moment, a health-centred response to the current crises would still provide the opportunity for a low-carbon, resilient future, which not only avoids the health harms of accelerated climate change, but also delivers improved health and wellbeing through the associated co-benefits of climate action. Such response would see countries promptly shifting away from fossil fuels, reducing their dependence on fragile international oil and gas markets, and accelerating a just transition to clean energy sources. A health-centred response would reduce the likelihood of the most catastrophic climate change impacts, while improving energy security, creating an opportunity for economic recovery, and offering immediate health benefits. Improvements in air quality would help to prevent the 1·2 million deaths resulting from exposure to fossil fuel-derived ambient PM2·5 in 2020 alone (indicator 3.3), and a health-centred energy transition would enhance low-carbon travel and increase urban green spaces, promoting physical activity, and improving physical and mental health. In the food sector, an accelerated transition to balanced and more plant-based diets would not only help reduce the 55% of agricultural sector emissions coming from red meat and milk production (indicator 3.5.1), but also prevent up to 11·5 million diet-related deaths annually (indicator 3.5.2), and substantially reduce the risk of zoonotic diseases. These health-focused shifts would reduce the burden of communicable and non-communicable diseases, reducing the strain on overwhelmed health-care providers. Importantly, accelerating climate change adaptation would lead to more robust health systems, minimising the negative impacts of future infectious disease outbreaks and geopolitical conflicts, and restoring the first line of defence of global populations.

EMERGING GLIMMERS OF HOPE: Despite decades of insufficient action, emerging, albeit few, signs of change provide some hope that a health-centred response might be starting to emerge. Individual engagement with the health dimensions of climate change, essential to drive and enable an accelerated response, increased from 2020 to 2021 (indicator 5.2), and coverage of health and climate change in the media reached a new record high in 2021, with a 27% increase from 2020 (indicator 5.1). This engagement is also reflected by country leaders, with a record 60% of 194 countries focusing their attention on the links between climate change and health in the 2021 UN General Debate, and with 86% of national updated or new NDCs making references to health (indicator 5.4). At the city level, local authorities are progressively identifying risks of climate change on the health of their populations (indicator 2.1.3), a first step to delivering a tailored response that strengthens local health systems. Although the health sector is responsible for 5·2% of all global emissions (indicator 3.6), it has shown impressive climate leadership, and 60 countries had committed to transitioning to climate-resilient and/or low-carbon or net-zero carbon health systems as part of the COP26 Health Programme, as of July, 2022. Signs of change are also emerging in the energy sector. Although total clean energy generation remains grossly insufficient, record high levels were reached in 2020 (indicator 3.1). Zero-carbon sources accounted for 80% of investment in electricity generation in 2021 (indicator 4.2.1), and renewable energies have reached cost parity with fossil fuel energies. As some of the highest emitting countries attempt to cut their dependence on oil and gas in response to the war in Ukraine and soaring energy prices, many are focusing on increasing renewable energy generation, raising hopes for a health-centred response. However, increased awareness and commitments should be urgently translated into action for hope to turn into reality.

DESIGN: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 flow checklist. A population-exposure-outcome framework was established. Population referred to the general global population of all ages, the exposure of interest was air pollution and its projection, and the outcome was the occurrence of NCDs attributable to air pollution and burden of disease (BoD) based on the health indices of mortality, morbidity, disability-adjusted life years, years of life lost and years lived with disability.

DATA SOURCES: The Web of Science, Ovid MEDLINE and EBSCOhost databases were searched for articles published from 2005 to 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES: The eligible articles were evaluated using the modified scale of a checklist for assessing the quality of ecological studies.

DATA EXTRACTION AND SYNTHESIS: Two reviewers searched, screened and selected the included studies independently using standardised methods. The risk of bias was assessed using the modified scale of a checklist for ecological studies. The results were summarised based on the projection of the BoD of NCDs attributable to air pollution.

RESULTS: This review included 11 studies from various countries. Most studies specifically investigated various air pollutants, specifically particulate matter <2.5 µm (PM2.5), nitrogen oxides and ozone. The studies used coupled-air quality and climate modelling approaches, and mainly projected health effects using the concentration-response function model. The NCDs attributable to air pollution included cardiovascular disease (CVD), respiratory disease, stroke, ischaemic heart disease, coronary heart disease and lower respiratory infections. Notably, the BoD of NCDs attributable to air pollution was projected to decrease in a scenario that promotes reduced air pollution, carbon emissions and land use and sustainable socioeconomics. Contrastingly, the BoD of NCDs was projected to increase in a scenario involving increasing population numbers, social deprivation and an ageing population.

CONCLUSION: The included studies widely reported increased premature mortality, CVD and respiratory disease attributable to PM2.5. Future NCD projection studies should consider emission and population changes in projecting the BoD of NCDs attributable to air pollution in the climate change era.