The mortality cost of carbon

Ecologically sustainable benchmarking of AI models for histopathology

Deep learning (DL) holds great promise to improve medical diagnostics, including pathology. Current DL research mainly focuses on performance. DL implementation potentially leads to environmental consequences but approaches for assessment of both performance and carbon footprint are missing. Here, we explored an approach for developing DL for pathology, which considers both diagnostic performance and carbon footprint, calculated as CO2 or equivalent emissions (CO2eq). We evaluated various DL architectures used in computational pathology, including a large foundation model, across two diagnostic tasks of low and high complexity. We proposed a metric termed 'environmentally sustainable performance' (ESPer), which quantitatively integrates performance and operational CO2eq during training and inference. While some DL models showed comparable diagnostic performance, ESPer enabled prioritizing those with less carbon footprint. We also investigated how data reduction approaches can improve the ESPer of individual models. This study provides an approach facilitating the development of environmentally friendly, sustainable medical AI.

Potential impacts of optimised care pathways on carbon impact of anaesthesia consultation-A monocenter prospective study

BACKGROUND

Global warming presents major public health challenges, with healthcare transportation significantly contributing to carbon dioxide equivalent emissions (eCO2). While the greenhouse effects of anaesthetic gases are well-documented, the eCO2 of pre-anaesthesia consultations remains underexplored. This study aims to evaluate and propose strategies to reduce the carbon impact of these consultations at a Tertiary University Hospital.

METHODS

In a prospective, observational study over one month, data were collected from patients attending pre-anaesthesia consultations. ECO2 emissions from transportation and electricity were calculated. To reduce emissions, several modifications to the care pathway were investigated, including teleconsultation, remote consultation, grouping of consultations, carpooling, and the promotion of public transport. The effects of current and optimised care pathways were then compared.

RESULTS

Data from 213 patients showed that 75% attended the hospital solely for pre-anaesthesia consultations, mostly by car (82%). The mean eCO2 per consultation was 22.4 kgCO2 (95% CI: 14.6-30.2). Implementing optimisation strategies in 65% of cases could reduce emissions to 5.6 kg CO2 (95% CI: 0.2-10.9) per consultation, leading to a 74% reduction and an annual saving of 274 t of eCO2.

DISCUSSION

Our study highlights the potential for significant reductions in the eCO2 of pre-anaesthesia consultations. The adaptation of the care pathway would largely involve grouping consultations and developing teleconsultations. These potential savings in greenhouse gas emissions are in the same order of magnitude as not using desflurane in the operating theatre and could be the next step towards greener anaesthesia.

Heat disproportionately kills young people: Evidence from wet-bulb temperature in Mexico

Recent studies project that temperature-related mortality will be the largest source of damage from climate change, with particular concern for the elderly whom it is believed bear the largest heat-related mortality risk. We study heat and mortality in Mexico, a country that exhibits a unique combination of universal mortality microdata and among the most extreme levels of humid heat. Combining detailed measurements of wet-bulb temperature with age-specific mortality data, we find that younger people who are particularly vulnerable to heat: People under 35 years old account for 75% of recent heat-related deaths and 87% of heat-related lost life years, while those 50 and older account for 96% of cold-related deaths and 80% of cold-related lost life years. We develop high-resolution projections of humid heat and associated mortality and find that under the end-of-century SSP 3-7.0 emissions scenario, temperature-related deaths shift from older to younger people. Deaths among under-35-year-olds increase 32% while decreasing by 33% among other age groups.

Association between Diet-Related Greenhouse Gas Emissions and Mortality among Japanese Adults: The Japan Collaborative Cohort Study

BACKGROUND

Planetary and human health are highly intertwined; our current food system is associated with high greenhouse gas emissions (GHGE) and burden of disease.

OBJECTIVE

The aim of this study was to investigate the associations of diet-related GHGE with all-cause and cause-specific mortality in Japan.

METHODS

This study included 58,031 Japanese adults (35,078 women and 22,953 men) 40-79 y of age who participated in the Japan Collaborative Cohort Study during the period 1988-1990. Diet-related GHGE was calculated from dietary intake estimated by a validated food frequency questionnaire and previously developed GHGE tables of each food and beverage. Participants were classified into quintiles of diet-related GHGE per kg food/d. Hazard ratios (HRs) of all-cause and cause-specific mortality were calculated using the Cox proportional hazard and restricted cubic spline models.

RESULTS

The average diet-related GHGE was 1,522   g - CO 2 -eq / kg  food / d . Over a period of 19.3 y (955,819 person-years) of median follow-up, 11,508 deaths were documented. After adjusting for lifestyle and medical history, in comparison with the fourth quintiles of diet-related GHGE, the first and fifth quintiles were associated with a higher risk of all-cause mortality: multivariable HR of all-cause mortality was 1.11 [95% confidence interval (CI): 1.05, 1.18] and 1.09 (95% CI: 1.03, 1.17) for the lowest and highest GHGE, respectively; those of cardiovascular disease mortality were 1.23 (95% CI: 1.10, 1.38) and 1.22 (95% CI: 1.08, 1.37), respectively. The diet-related GHGE range with the lowest HR of all-cause mortality was 1,400 - 1,600   g - CO 2 eq / kg food/d (p for nonlinearity < 0.001 ). Replacing one serving of red meat with one serving of pulses was inversely associated with all-cause mortality (HR = 0.96 ; 95% CI: 0.93, 0.99) and GHGE (mean change, - 347   g - CO 2 -eq / kg / d ; 95% CI: - 353 , - 342 ).

DISCUSSION

Diet-related GHGE was associated with all-cause and cardiovascular disease mortality in a U-shaped fashion. This finding could be useful for creating a policy for sustainable shifts in dietary habits that will benefit the population and environmental health. https://doi.org/10.1289/EHP14935.

Study on the Precise Evaluation of Environmental Impacts of Air Pollution in Cold Regions Using the Cost Control Method

Objective: With the acceleration of industrialization, air pollution has become a global environmental issue, particularly in cold regions where the unique climatic and geographical conditions give rise to distinctive types of air pollution and impacts. Considering the economic evaluation of environmental damage is crucial for effective pollution control policies, this study aims to provide a more precise environmental damage assessment method through the Improved Virtual Control Cost Method (IVCCM) to optimize air pollution governance strategies in cold regions. Method: This study utilizes a case study of a major company producing methanol and coal-based natural gas, where the emissions from the boiler exhaust exceeded the prescribed standards for particulate matter, sulfur dioxide, and nitrogen oxides during a specific period. By employing a segmented counting approach that accounts for downtime, precise calculations were conducted for the actual periods of excess emissions. Adjustments were made to the calculation coefficients within the Virtual Control Cost Method to more accurately reflect the ecological damage caused by air pollution. Results: The IVCCM calculations revealed that the total environmental loss caused by the company’s excessive air pollution emissions amounted to USD 1.6844 million, significantly lower than the original calculation method (USD 2.1885 million). Specifically, the environmental losses due to particulate matter, sulfur dioxide, and nitrogen oxides were USD 0.0032 million, USD 0.3600 million, and USD 1.3212 million, respectively. Conclusions: The IVCCM enables a more precise assessment and prediction of ecological environmental damage caused by air pollution in cold regions. Compared to traditional methods, it effectively reduces assessment costs, mitigates disputes arising from unclear parameter values and calculation methods, and facilitates the development of more rational environmental protection policies and measures.

Assessing the Environmental and Downstream Human Health Impacts of Decentralizing Cancer Care

Importance

Greenhouse gas (GHG) emissions from health care are substantial and disproportionately harm persons with cancer. Emissions from a central component of oncology care, outpatient clinician visits, are not well described, nor are the reductions in emissions and human harms that could be obtained through decentralizing this aspect of cancer care (ie, telemedicine and local clinician care when possible).

Objective

To assess potential reductions in GHG emissions and downstream health harms associated with telemedicine and fully decentralized cancer care.

Design, Setting, and Participants

This population-based cohort study and counterfactual analyses using life cycle assessment methods analyzed persons receiving cancer care at Dana-Farber Cancer Institute between May 2015 and December 2020 as well as persons diagnosed with cancer over the same period from the Cancer in North America (CiNA) public dataset. Data were analyzed from October 2023 to April 2024.

Main Outcomes and Measures

The adjusted per-visit day difference in GHG emissions in kilograms of carbon dioxide (CO2) equivalents between 2 periods: an in-person care model period (May 2015 to February 2020; preperiod) and a telemedicine period (March to December 2020; postperiod), and the annual decrease in disability-adjusted life-years in a counterfactual model where care during the preperiod was maximally decentralized nationwide.

Results

Of 123 890 included patients, 73 988 (59.7%) were female, and the median (IQR) age at first diagnosis was 59 (48-68) years. Patients were seen over 1.6 million visit days. In mixed-effects log-linear regression, the mean absolute reduction in per-visit day CO2 equivalent emissions between the preperiod and postperiod was 36.4 kg (95% CI, 36.2-36.6), a reduction of 81.3% (95% CI, 80.8-81.7) compared with the baseline model. In a counterfactual decentralized care model of the preperiod, there was a relative emissions reduction of 33.1% (95% CI, 32.9-33.3). When demographically matched to 10.3 million persons in the CiNA dataset, decentralized care would have reduced national emissions by 75.3 million kg of CO2 equivalents annually; this corresponded to an estimated annual reduction of 15.0 to 47.7 disability-adjusted life-years.

Conclusions and Relevance

This cohort study found that using decentralization through telemedicine and local care may substantially reduce cancer care's GHG emissions; this corresponds to small reductions in human mortality.

Policy approaches to decarbonising the transport sector in Aotearoa New Zealand: modelling equity, population health, and health-system effects

BACKGROUND

Health co-benefits are a key potential advantage of transport decarbonisation policy. However, health effects will occur in the context of existing transport-health inequities and decarbonisation policies will themselves affect inequities. This research examines the effects of national decarbonisation pathways for transport on population health, health inequity, and health-system costs in Aotearoa New Zealand.

METHODS

We modelled the health, health-system, and environmental impacts of two pathways to net zero for transport developed by the New Zealand Climate Change Commission using a proportional multistate lifetable model. The behaviour pathway emphasises a mixed approach, including reduced driving, increased cycling and use of public transport, and light vehicle electrification, and the technology pathway focuses on vehicle electrification. We used data from transport, environmental, population health, and health-care sources to populate the model. We simulated changes in health effects through the pathways of physical activity, air pollution (PM2·5 and NO2), and injury for the Aotearoa New Zealand population from 2018 to 2050. We modelled impacts for Māori (the Indigenous People of Aotearoa) and non-Māori. For each pathway to net zero, we calculated changes in overall health-adjusted life-years (HALYs), age-standardised HALYs, and rate ratios for Māori and non-Māori. We also calculated changes in health-system costs and transport greenhouse gas emissions. 95% uncertainty intervals (95% UIs) were derived for all model outputs by use of a Monte Carlo simulation.

FINDINGS

Both pathways show improvements in population health, reductions in health-system costs, and reduced lifecycle greenhouse gas emissions compared with baseline, although health gains were substantially larger in the behaviour pathway. For example, an extra 2100 HALYs (95% UI 1500-3100) were gained in the behaviour scenario compared with baseline. Health gains were 20-30% larger for Māori than non-Māori in both pathways, although more HALYs were gained by Māori in the behaviour pathway. For the cohort aged 0-4 years in 2018, healthy life expectancy differences between Māori and non-Māori reduced by 0·5% in the behaviour pathway over their lifetime. HALYs gained by Māori and non-Māori were altered substantially depending on assumptions about the equity of the implemented pathway.

INTERPRETATION

Decarbonising transport might improve overall population health, save the health system money, and reduce health inequities between Māori and non-Māori. Pathways that increase physical activity have a larger effect on population health than those that rely on low-emission vehicles. The effects on inequity between Māori and non-Māori are larger in the behaviour pathway than in the technology pathway but dependent on how equitably policies supporting decarbonisation are implemented.

FUNDING

Health Research Council of New Zealand and University of Otago.

Measuring and valuing the health co-benefits of climate change mitigation: a scoping review

Despite growing interest in the health co-benefits of climate change mitigation actions, there is little recent evidence on the appropriateness of the measurement techniques being used to estimate them. We did a scoping review to identify the different approaches that have been used to measure and value health co-benefits in the climate change mitigation literature. We searched three databases (EBSCOhost, Web of Science, and MEDLINE Ovid) to identify relevant papers published between 2010 and 2023, and identified 267 studies that met our inclusion criteria to be included in the review. We found that health co-benefit studies are more typically published in the environmental science literature than in health journals. Despite calls going back many years for greater standardisation in methods, we found a highly diverse set of health measures and valuation approaches still in use. The majority of studies (232 [87%]) measured only near-term health co-benefits from reduced air pollution, and only 13 (5%) studies incorporated the longer term health benefits from mitigating the future health harms of climate change. Just over half the studies included monetary valuation of health co-benefits, using a variety of valuation approaches. Public and planetary health researchers, epidemiologists, and health economists should seek to engage more actively with those undertaking research in health co-benefits. This would allow consideration of how best to reconcile differing perspectives and techniques, how to achieve better standardisation of measurement and valuation, and how to extend the generally narrow focus of current health co-benefit studies to become more holistic and comprehensive.

Projected environmental and public health benefits of extended-interval dosing: an analysis of pembrolizumab use in a US national health system

BACKGROUND

Health care is a major source of greenhouse gas emissions, leading to climate change and public health harms. Changes are needed to improve the environmental sustainability of health-care practices, but such changes should not sacrifice patient outcomes or financial sustainability. Alternative dosing strategies that reduce the frequency with which specialty drugs are administered, without sacrificing patient outcomes, are an attractive possibility for improving environmental sustainability. We sought to inform environmentally sustainable cancer care by estimating and comparing the environmental and financial effects of alternative, clinically equivalent strategies for pembrolizumab administration.

METHODS

We conducted a retrospective analysis using a cohort of patients from the Veterans Health Administration (VHA) in the USA who received one or more pembrolizumab doses between May 1, 2020, and Sept 30, 2022. Using baseline, real-world administration of pembrolizumab, we generated simulated pembrolizumab use data under three near-equivalent counterfactual pembrolizumab administration strategies defined by combinations of weight-based dosing, pharmacy-level vial sharing and dose rounding, and extended-interval dosing (ie, every 6 weeks). For each counterfactual dosing strategy, we estimated greenhouse gas emissions related to pembrolizumab use across the VHA cohort using a deterministic environmental impact model that estimated greenhouse gas emissions due to patient travel, drug manufacture, and medical waste as the primary outcome measure.

FINDINGS

We identified 7813 veterans who received at least one dose of pembrolizumab-containing therapy in the VHA during the study period. 59 140 pembrolizumab administrations occurred in the study period, of which 46 255 (78·2%) were dosed at 200 mg every 3 weeks, 12 885 (21·8%) at 400 mg every 6 weeks, and 14 955 (25·3%) were coadministered with infusional chemotherapies. Adoption of weight-based, extended-interval pembrolizumab dosing (4 mg/kg every 6 weeks) and pharmacy-level stewardship strategies (ie, dose rounding and vial sharing) for all pembrolizumab infusions would have resulted in 24·7% fewer administration events than baseline dosing (44 533 events vs 59 140 events) and an estimated 200 metric tons less CO2 emitted per year as a result of pembrolizumab use within the VHA (650 tons vs 850 tons of CO2, a relative reduction of 24%), largely due to reductions in distance travelled by patients to receive treatment. Similar results were observed when weight-based and extended-interval dosing were applied only to pembrolizumab monotherapy and pembrolizumab in combination with oral therapies.

INTERPRETATION

Alternative pembrolizumab administration strategies might have environmental advantages over the current dosing and compounding paradigms. Specialty medication dosing can be optimised for health-care spending and environmental sustainability without sacrificing clinical outcomes.

FUNDING

None.

Evaluating the Impact of Telehealth on Carbon Footprint During Three Phases of the Pandemic at a Rural Academic Medical Center

Background: Climate change is primarily driven by greenhouse gases, such as carbon dioxide (CO2). Telehealth visits have been found to mitigate carbon emissions by reducing patient and physician transport. Dartmouth Hitchcock Medical Center (DHMC) is the most rural academic medical center in the country, serving a population where the majority of patients reach the hospital by car. No large study or systematic review has evaluated the impact of telehealth visits on CO2 emissions (CO2e) across multiple specialties in a purely rural setting. Further, no sizable rurally focused study has compared CO2e avoided during the various stages of the pandemic. Methods: We extracted data for all outpatient telehealth visits at DHMC from three periods: prepandemic, early pandemic, and late pandemic. The extracted data included the pandemic stage of the virtual visit, the type of visit (video or telephone), the specialty, and the distance from the patient's home to DHMC. Results: The total CO2e avoided among all three pandemic stages analyzed in this study was 23,658,898 kg (n = 251,832). During period 1, the mean driving distance = 159.0 miles; CO2e avoided per encounter = 128.3 kg; period 2, mean distance = 84.85 miles; average CO2e avoided per encounter = 68.47 CO2e kg; and period 3, mean distance = 112.9 miles; average CO2e avoided per encounter = 91.08 kg. Conclusions: This data supported long distances to the medical center and large savings in CO2e avoided across multiple specialties that spanned all pandemic periods. Further, this level of averted emissions could translate to over $3M in saved fuel costs and the avoidance of six excess deaths. While discussions of the future of telehealth commonly focus on access, use cases, technology, costs, and satisfaction, the impact on carbon footprint is an additional important metric, particularly in largely rural regions.

Reducing the carbon footprint of general anaesthesia: a comparison of total intravenous anaesthesia vs. a mixed anaesthetic strategy in 47,157 adult patients

Global warming is a major public health concern. Volatile anaesthetics are greenhouse gases that increase the carbon footprint of healthcare. Modelling studies indicate that total intravenous anaesthesia is less carbon intensive than volatile anaesthesia, with equivalent quality of care. In this observational study, we aimed to apply the findings of previous modelling studies to compare the carbon footprint per general anaesthetic of an exclusive TIVA strategy vs. a mixed TIVA-volatile strategy. This comparative retrospective study was conducted over 2 years in two French hospitals, one using total intravenous anaesthesia only and one using a mixed strategy including both intravenous and inhalation anaesthetic techniques. Based on pharmacy procurement records, the quantity of anaesthetic sedative drugs was converted to carbon dioxide equivalents. The primary outcome was the difference in carbon footprint of hypnotic drugs per intervention between the two strategies. From 1 January 2021 to 31 December 2022, 25,137 patients received general anaesthesia in the hospital using the total intravenous anaesthesia strategy and 22,020 in the hospital using the mixed strategy. The carbon dioxide equivalent footprint of hypnotic drugs per intervention in the hospital using the total intravenous anaesthesia strategy was 20 times lower than in the hospital using the mixed strategy (emissions of 2.42 kg vs. 48.85 kg carbon dioxide equivalent per intervention, respectively). The total intravenous anaesthesia strategy significantly reduces the carbon footprint of hypnotic drugs in general anaesthesia in adult patients compared with a mixed strategy. Further research is warranted to assess the risk-benefit ratio of the widespread adoption of total intravenous anaesthesia.

Improving consistency in estimating future health burdens from environmental risk factors: Case study for ambient air pollution

Future changes in exposure to risk factors should impact mortality rates and population. However, studies commonly use mortality rates and population projections developed exogenously to the health impact assessment model used to quantify future health burdens attributable to environmental risks that are therefore invariant to projected exposure levels. This impacts the robustness of many future health burden estimates for environmental risk factors. This work describes an alternative methodology that more consistently represents the interaction between risk factor exposure, population and mortality rates, using ambient particulate air pollution (PM2.5) as a case study. A demographic model is described that estimates future population based on projected births, mortality and migration. Mortality rates are disaggregated between the fraction due to PM2.5 exposure and other factors for a historic year, and projected independently. Accounting for feedbacks between future risk factor exposure and population and mortality rates can greatly affect estimated future attributable health burdens. The demographic model estimates much larger PM2.5-attributable health burdens with constant 2019 PM2.5 (∼10.8 million deaths in 2050) compared to a model using exogenous population and mortality rate projections (∼7.3 million), largely due to differences in mortality rate projection methods. Demographic model-projected PM2.5-attributable mortality can accumulate substantially over time. For example, ∼71 million more people are estimated to be alive in 2050 when WHO guidelines (5 µg m-3) are achieved compared to constant 2019 PM2.5 concentrations. Accounting for feedbacks is more important in applications with relatively high future PM2.5 concentrations, and relatively large changes in non-PM2.5 mortality rates.

Carbon footprint of hospital laundry: a life-cycle assessment

OBJECTIVES

To assess greenhouse gas (GHG) emissions from a regional hospital laundry unit, and model ways in which these can be reduced.

DESIGN

A cradle to grave process-based attributional life-cycle assessment.

SETTING

A large hospital laundry unit supplying hospitals in Southwest England.

POPULATION

All laundry processed through the unit in 2020-21 and 2021-22 financial years.

PRIMARY OUTCOME MEASURE

The mean carbon footprint of processing one laundry item, expressed as in terms of the global warming potential over 100 years, as carbon dioxide equivalents (CO2e).

RESULTS

Average annual laundry unit GHG emissions were 2947 t CO2e. Average GHG emissions were 0.225 kg CO2e per item-use and 0.5080 kg CO2e/kg of laundry. Natural gas use contributed 75.7% of on-site GHG emissions. Boiler electrification using national grid electricity for 2020-2022 would have increased GHG emissions by 9.1%, however by 2030 this would reduce annual emissions by 31.9% based on the national grid decarbonisation trend. Per-item transport-related GHG emissions reduce substantially when heavy goods vehicles are filled at ≥50% payload capacity. Single-use laundry item alternatives cause significantly higher per-use GHG emissions, even if reusable laundry were transported long distances and incinerated at the end of its lifetime.

CONCLUSIONS

The laundry unit has a large carbon footprint, however the per-item GHG emissions are modest and significantly lower than using single-use alternatives. Future electrification of boilers and optimal delivery vehicle loading can reduce the GHG emissions per laundry item.

The carbon cost of inappropriate endoscopy

BACKGROUND AND AIMS

Digestive endoscopy is a resource-intensive activity with a conspicuous carbon footprint and an estimated rate of inappropriateness. However, the carbon costs of inappropriate endoscopic procedures still remain obscure. Here we evaluated the environmental impact of inappropriate endoscopic examinations.

METHODS

We calculated the carbon cost of a standard endoscopic procedure (EGD and colonoscopy [CLS]), taking into account the items (eg, disposable materials, personal protective equipment) and energy required for the endoscopy procedure itself and the cleaning process. The rates of inappropriateness and the mortality cost of carbon (MCC) of endoscopic examinations in different scenarios were calculated.

RESULTS

EGD and CLS presented a carbon cost of 5.43 kg and 6.71 kg of CO2, respectively. Different scenarios were evaluated, according to the number of endoscopic procedures performed in Italy per 1000 inhabitants and the reported data on their inappropriateness. The carbon cost of inappropriate EGD and CLS in Italy was 4133 CO2 metric tons per year (MCC, .93), ranging from 3527 to 4749, and equivalent to 1,760,446 L of gasoline consumed. Applying the same data to the European population, the estimated carbon footprint of inappropriate digestive endoscopy in Europe was 30,804 metric tons.

CONCLUSIONS

The environmental impact of inappropriate endoscopic procedures in Europe is remarkable. These results highlight the need to adopt novel strategies aimed at reducing both the carbon footprint of digestive endoscopy and the rate of inappropriate procedures.

Economic valuation of temperature-related mortality attributed to urban heat islands in European cities

As the climate warms, increasing heat-related health risks are expected, and can be exacerbated by the urban heat island (UHI) effect. UHIs can also offer protection against cold weather, but a clear quantification of their impacts on human health across diverse cities and seasons is still being explored. Here we provide a 500 m resolution assessment of mortality risks associated with UHIs for 85 European cities in 2015-2017. Acute impacts are found during heat extremes, with a 45% median increase in mortality risk associated with UHI, compared to a 7% decrease during cold extremes. However, protracted cold seasons result in greater integrated protective effects. On average, UHI-induced heat-/cold-related mortality is associated with economic impacts of €192/€ - 314 per adult urban inhabitant per year in Europe, comparable to air pollution and transit costs. These findings urge strategies aimed at designing healthier cities to consider the seasonality of UHI impacts, and to account for social costs, their controlling factors, and intra-urban variability.

Economic uncertainty and population health: insights from emerging markets and developing countries

This study employs a Bayesian panel vector autoregressive model to examine the impact of economic uncertainty on public health, using an annual, country-level panel dataset of 103 emerging markets and developing countries spanning the years 1995 through 2019. The results from the full sample suggest that the immediate effects of heightened economic uncertainty on health are marginal, yet it may engender prolonged life expectancy and lowered mortality rates. The analysis unveils considerable heterogeneities among various country classifications. The health-enhancing effects of economic uncertainty are predominantly discernible in emerging markets, low-income and upper-middle-income countries. Additionally, a diminution in suicide rates, attributed to escalated economic uncertainty, is uniquely detected in upper-middle-income countries. Furthermore, economic growth and healthcare expenditure emerge as paramount determinants in bolstering overall population health, particularly in lower-middle-income countries. The detrimental effect of environmental pollution on health is more pronounced in emerging markets and middle-income nations. Excluding high-income countries, it is essential to emphasize the beneficial health outcomes resulting from financial development and globalization, as well as the deleterious effects of environmental pollution. Lastly, several policy implications aligned with the findings are outlined, providing a roadmap for decision-makers in these diverse economies to promote better health outcomes.

Mitigating the effects of climate change on human health with vaccines and vaccinations

Climate change represents an unprecedented threat to humanity and will be the ultimate challenge of the 21st century. As a public health consequence, the World Health Organization estimates an additional 250,000 deaths annually by 2030, with resource-poor countries being predominantly affected. Although climate change's direct and indirect consequences on human health are manifold and far from fully explored, a growing body of evidence demonstrates its potential to exacerbate the frequency and spread of transmissible infectious diseases. Effective, high-impact mitigation measures are critical in combating this global crisis. While vaccines and vaccination are among the most cost-effective public health interventions, they have yet to be established as a major strategy in climate change-related health effect mitigation. In this narrative review, we synthesize the available evidence on the effect of climate change on vaccine-preventable diseases. This review examines the direct effect of climate change on water-related diseases such as cholera and other enteropathogens, helminthic infections and leptospirosis. It also explores the effects of rising temperatures on vector-borne diseases like dengue, chikungunya, and malaria, as well as the impact of temperature and humidity on airborne diseases like influenza and respiratory syncytial virus infection. Recent advances in global vaccine development facilitate the use of vaccines and vaccination as a mitigation strategy in the agenda against climate change consequences. A focused evaluation of vaccine research and development, funding, and distribution related to climate change is required.

Recommendations Emerging from Carbon Emissions Estimations of the Society for Neuroscience Annual Meeting

The annual Society for Neuroscience (SfN) meeting yields significant, measurable impacts that conflict with the environmental commitment of the Society and the Intergovernmental Panel on Climate Change (IPCC) recommendations to address the climate emergency (IPCC, 2018). We used 12,761 presenters' origins, two online carbon calculators, and benchmark values to estimate 2018 meeting-related travel, event venue operations, and hotel accommodation emissions. Presenters' conference travel resulted in between 17,298 and 8690 tons of atmospheric carbon dioxide (t CO2), with or without radiative forcing index factors. Over 92% of authors traveled by air and were responsible for >99% of total travel-related emissions. Extrapolations based on 28,691 registrants yielded between 69,592.60 metric tons of carbon dioxide equivalents (t CO2e) and 38,010.85 t CO2 from travel. Comparatively, authors' and registrants' hotel accommodation emissions equaled 429 and 965 t CO2e, whereas operation of the San Diego Convention Center equaled ∼107 t CO2e. We relate SfN meeting-related emissions to potential September Arctic Sea ice loss, labor productivity loss in lower-income equatorial countries, and future temperature-related deaths. We estimate emissions reductions of between 23% and 78% by incentivizing between 10% and 50% of the most distant registrants to attend virtually or connecting between two and seven in-person hubs virtually. Completely virtual meetings may yield a reduction of >99% relative to centralized in-person meetings and increase participation of women, queer and transgender scientists, and scientists from low- and middle-income countries. We strongly recommend adopting alternative meeting modes such as four or more in-person global hubs connected virtually by 2030 and fully virtual by 2050.

Alternative Trastuzumab Dosing Schedules Are Associated With Reductions in Health Care Greenhouse Gas Emissions

PURPOSE

Cancer care-related greenhouse gas (GHG) emissions harm human health. Many cancer drugs are administered at greater-than-necessary doses, frequencies, and durations. Alternative dosing strategies may enable reductions in cancer care GHG emissions without compromising patient outcomes.

MATERIALS AND METHODS

We used streamlined life-cycle analysis in a case-control simulation to estimate the relative reductions in GHG emissions that would be expected to result from using each of three alternative dosing strategies of trastuzumab (6-month adjuvant treatment duration, once every 4-week dosing, and both) in human epidermal growth factor receptor 2 (HER2)+ breast cancer. Using primary data and conversion factors from the environmental science literature, we estimated per-patient relative reduction in GHG emissions and, using SEER data, health impacts (in terms of disability-adjusted life-years [DALYs] and excess mortality per kg CO2) on bystanders for each alternative dosing strategy.

RESULTS

Compared with the trastuzumab dosing strategy commonly used at baseline (12-month duration of adjuvant therapy and once every 3-week dosing in all settings), adoption of both 6-month adjuvant trastuzumab and once every 4-week trastuzumab dosing would reduce GHG emissions by 4.5%, 18.7%, and 14.6% in the neoadjuvant, adjuvant, and metastatic settings, respectively. We estimate that US-based adoption of alternative trastuzumab dosing would reduce annual DALYs and excess lives lost due to environmental impact of US-based trastuzumab therapy for HER2+ breast cancer by 1.5 and 0.9, respectively.

CONCLUSION

Alternative dosing strategies may materially reduce the population health impacts of cancer care by reducing environmental impact. Regulatory decision making and health technology assessments should consider a treatment's environmental and population health impacts. Clinical trials of alternative dosing strategies are justified on the basis of environmental and population health impacts.

Climate change views examined through a behavioral medicine frame: are there potential target mechanisms for change beyond political ideology?

The threat of climate change is associated with both profound health consequences and failures by many individuals to take preventive actions. Behavioral science research on health behavior engagement may serve as a lens through which to better understand attitudes associated with the threat of climate change. This study was designed to examine individual differences in attitudinal responses to climate change, understanding the degree to which these responses can be predicted by both political beliefs and more readily modified psychological factors commonly associated with health behavior engagement: locus of control, anxiety sensitivity, delay discounting, and intolerance of uncertainty. Participants (N = 234) were US adults (62% male; 57% Non-Hispanic White; 44% Democrat) who completed an online survey. Stepwise multiple linear regressions examined which variables provided non-redundant prediction in models of climate change beliefs and concerns. In addition to providing support for the role of political affiliation and related ideology in climate change views (9-23% variance), this study underscores the importance of a behavioral health frame in understanding climate change concerns and beliefs. Known risk factors for negative health behaviors - prominently, locus of control, anxiety sensitivity, and delay discounting - contributed strongly to the understanding of these views, accounting for 4-28% of variance. Our findings encourage greater attention to health behavior-related constructs for understanding attitudes relevant to climate change action.

Fair pathways to net-zero healthcare

Over the past decade, it has become clear that the health sector is not only at risk from climate change but also a major polluter of greenhouse gases. In November 2021, the World Health Organization and partners launched the COP26 Health Programme for sustainable, climate-resilient and low-carbon health systems, and have since established the Alliance for Transformative Action on Climate and Health to support its implementation. Given the wide variation in health financing, carbon emissions and unmet health needs across the world, fair sharing of the remaining carbon budget and health gains will be critical. In this Perspective, we explore the challenges and opportunities of healthcare decarbonization, outlining the principles of fair pathways to net-zero healthcare that are attentive to health and socioeconomic inequalities within and between countries.

Nuclear power generation phase-outs redistribute US air quality and climate-related mortality risk

We explore how nuclear shut-downs in the United States could affect air pollution, climate and health with existing and alternative grid infrastructure. We develop a dispatch model to estimate emissions of CO2, NO x and SO2 from each electricity-generating unit, feeding these emissions into a chemical transport model to calculate effects on ground-level ozone and fine particulate matter (PM2.5). Our scenario of removing nuclear power results in compensation by coal, gas and oil, resulting in increases in PM2.5 and ozone that lead to an extra 5,200 annual mortalities. Changes in CO2 emissions lead to an order of magnitude higher mortalities throughout the twenty-first century, incurring US$11-180 billion of damages from 1 year of emissions. A scenario exploring simultaneous closures of nuclear and coal plants redistributes health impacts and a scenario with increased penetration of renewables reduces health impacts. Inequities in exposure to pollution are persistent across all scenarios-Black or African American people are exposed to the highest relative levels of pollution.

Interview Without Harm: Reimagining Medical Training's Financially and Environmentally Costly Interview Practices

The looming threat of climate change urgently calls for reimagining unsustainable systems and practices, including academia's culture of emissions-intensive travel. Given that medical educators are uniquely invested in the future of the trainees they represent, this reimagination can and should begin with medical education. Making significant reforms to the application process has historically been challenging, but the COVID-19 pandemic catalyzed an abrupt shift from in-person to virtual interviews for medical school, residency, and fellowship. Programs and applicants alike demonstrated resilience, innovation, and satisfaction in adapting to virtual interviews during 2 full application cycles. This restructuring has prompted consideration of the necessity of environmentally costly, expensive, and time-consuming cross-country travel for single-day interviews. However, evolving conversations about the future of medical training interviews have not prioritized environmental impact, despite the sizeable historical emissions generated by interview-related travel and the incompatibility between ecological damage and population health. Beyond environmental impact, virtual interviews are more equitable, with significantly fewer financial costs, and they are more efficient, requiring less time off from school or work. Many concerns associated with virtual interviews, including interview inflation and limited applicant exposure to programs and their surrounding areas, can be addressed via creative and structural solutions, such as interview caps and in-person second-look programs. The medical training interview process underwent a forced restructuring due to the unprecedented disruption caused by COVID-19. This moment presents a strategic inflection point for medical education leadership to build on the momentum and permanently transform the process by focusing on sustainability and equity.

HealthcareLCA: an open-access living database of health-care environmental impact assessments

Anthropogenic environmental change negatively effects human health and is increasing health-care system demand. Paradoxically, the provision of health care, which itself is a substantial contributor to environmental degradation, is compounding this problem. There is increasing willingness to transition towards sustainable health-care systems globally and ensuring that strategy and action are informed by best available evidence is imperative. In this Personal View, we present an interactive, open-access database designed to support this effort. Functioning as a living repository of environmental impact assessments within health care, the HealthcareLCA database collates 152 studies, predominantly peer-reviewed journal articles, into one centralised and publicly accessible location, providing impact estimates (currently totalling 3671 numerical values) across 1288 health-care products and processes. The database brings together research generated over the past two decades and indicates exponential field growth.

Minimizing sevoflurane wastage by sensible use of automated gas control technology in the flow-i workstation: an economic and ecological assessment

Both ecological and economic considerations dictate minimising wastage of volatile anaesthetics. To reconcile apparent opposing stakes between ecological/economical concerns and stability of anaesthetic delivery, new workstations feature automated software that continually optimizes the FGF to reliably obtain the requested gas mixture with minimal volatile anaesthetic waste. The aim of this study is to analyse the kinetics and consumption pattern of different approaches of sevoflurane delivery with the same 2% end-tidal goal in all patients. The consumption patterns of sevoflurane of a Flow-i were retrospectively studied in cases with a target end-tidal sevoflurane concentration (Etsevo) of 2%. For each setting, 25 cases were included in the analysis. In Automatic Gas Control (AGC) regulation with software version V4.04, a speed setting 6 was observed; in AGC software version V4.07, speed settings 2, 4, 6 and 8 were observed, as well as a group where a minimal FGF was manually pursued and a group with a fixed 2 L/min FGF. In 45 min, an average of 14.5 mL was consumed in the 2L-FGF group, 5.0 mL in the minimal-manual group, 7.1 mL in the AGC4.04 group and 6.3 mL in the AGC4.07 group. Faster speed AGC-settings resulted in higher consumption, from 6.0 mL in speed 2 to 7.3 mL in speed 8. The Etsevo target was acquired fastest in the 2L-FGF group and the Etsevo was more stable in the AGC groups and the 2L-FGF groups. In all AGC groups, the consumption in the first 8 min was significantly higher than in the minimal flow group, but then decreased to a comparable rate. The more recent AGC4.07 algorithm was more efficient than the older AGC4.04 algorithm. This study indicates that the AGC technology permits very significant economic and ecological benefits, combined with excellent stability and convenience, over conventional FGF settings and should be favoured. While manually regulated minimal flow is still slightly more economical compared to the automated algorithm, this comes with a cost of lower precision of the Etsevo. Further optimization of the AGC algorithms, particularly in the early wash-in period seems feasible. In AGC mode, lower speed settings result in significantly lower consumption of sevoflurane. Routine clinical practice using what historically is called "low flow anaesthesia" (e.g. 2 L/min FGF) should be abandoned, and all anaesthesia machines should be upgraded as soon as possible with automatic delivery technology to minimize atmospheric pollution with volatile anaesthetics.

Improving executive compensation in the fossil fuel sector to influence green behaviors

The effects of climate change are being felt around the world, and the calls to mitigate are growing louder. In hopes of responding to this call, we examine strategic compensation practices as innovative solutions for tackling climate change. We employ a fixed panel analysis and examine organizational data from an array of global fossil fuel organizations—arguably the principal climate change contributors. Our findings suggest that executive stock-option compensation oriented around a 3-year or more vesting period will enhance organizational green behaviors. The contributions of this study add to the green human resource management literature in offering new perspectives on how compensation practices can enhance green behaviors and clarify key misconceptions related to linking sustainability targets to firm-level compensation schemes.

The biospheric emergency calls for scientists to change tactics

Our current economic and political structures have an increasingly devastating impact on the Earth's climate and ecosystems: we are facing a biospheric emergency, with catastrophic consequences for both humans and the natural world on which we depend. Life scientists - including biologists, medical scientists, psychologists and public health experts - have had a crucial role in documenting the impacts of this emergency, but they have failed to drive governments to take action in order to prevent the situation from getting worse. Here we, as members of the movement Scientist Rebellion, call on life scientists to re-embrace advocacy and activism - which were once hallmarks of academia - in order to highlight the urgency and necessity of systemic change across our societies. We particularly emphasise the need for scientists to engage in nonviolent civil resistance, a form of public engagement which has proven to be highly effective in social struggles throughout history.

Measurement of China's provincial social cost of carbon under the integrated socioeconomic-climate framework

The social cost of carbon is a tool for assessing the appropriateness of emission reduction measures and climate policy, and is affected by socioeconomic and climatic factors. This study aimed to explore the impact of socioeconomic factors and climate on the social cost of carbon; to this end, this study considered Chinese provinces as the focus of research. This study constructed an integrated framework for carbon emissions considering socioeconomic and climatic factors, which consisted of shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs). Subsequently, social cost of the carbon estimation model was used to calculate the social cost of carbon for China's provinces from 2022 to 2100 under different carbon emission scenarios. The results show that: under most carbon emission scenarios, provinces with a high social cost of carbon are located in the eastern developed region. For instance, Jiangsu and Guangdong had the highest values of 6.31 $/tC. Second, SSPs that are highly dependent on fossil fuels have a high social cost of carbon, which is higher than 60 $/tC in 2022 in China. The social cost of carbon under other SSPs is at a fluctuating value of 40 $/tC. Third, in terms of RCPs, the social cost of carbon for the middle baseline emission scenario (RCP6.0) is considerably lower than that for the high baseline emission scenario (RCP8.0), and the difference between them is 3.7 times that of two medium emission scenarios (RCP6.0 and RCP4.5). Fourth, there is a substantial difference between the dynamic and fixed discount rates in the social cost of carbon in the same scenario. Studying the impact of socioeconomic and climatic factors on the social cost of carbon will help in its regulation and provide a scientific basis for Chinese provinces to optimize climate policies and emission reduction measures.

Evaluation of the potential use of e-fuels in the European aviation sector: a comprehensive economic and environmental assessment including externalities

The decarbonisation of the transportation sector is key to meeting the climate goals. Whilst the electrification of road passenger transportation is proving to be a viable low-carbon solution in many contexts, a viable pathway towards a decarbonised aviation sector remains opaque. In this context, so-called e-fuels produced via the combination of H2O, CO2 and renewable energy may have promise owing to their compatibility with existing infrastructure. Most studies on e-fuels focus only on the economic dimension, neglecting their environmental performance and associated costs. Here, we present a techno-economic evaluation and cradle-to-grave life cycle assessment of Fischer-Tropsch (FT) e-jet fuels produced at different locations in Europe from a range of CO2 and green H2 sources to comprehensively assess their potential in aviation, explicitly accounting for externalities. Our results show that e-jet fuel is at present much more expensive (at least 5.4-fold) than its fossil analogue, even when externalities are included (i.e., at least 2.3 fold the current cost of fossil jet fuel). Furthermore, e-jet fuels could exacerbate the damage to human health and ecosystems despite showing lower carbon footprint and resource scarcity impacts than their fossil counterparts. Overall, e-jet fuel could become more economically and environmentally attractive by reducing the cost and impact of CO2 and green H2 and, more specifically, the electricity used in their production processes. In this regard, the production plant's location emerges as a critical factor due to the costs associated with balancing the intermittency of site-specific renewables.

Comprehensive evidence implies a higher social cost of CO2

The social cost of carbon dioxide (SC-CO2) measures the monetized value of the damages to society caused by an incremental metric tonne of CO2 emissions and is a key metric informing climate policy. Used by governments and other decision-makers in benefit-cost analysis for over a decade, SC-CO2 estimates draw on climate science, economics, demography and other disciplines. However, a 2017 report by the US National Academies of Sciences, Engineering, and Medicine1 (NASEM) highlighted that current SC-CO2 estimates no longer reflect the latest research. The report provided a series of recommendations for improving the scientific basis, transparency and uncertainty characterization of SC-CO2 estimates. Here we show that improved probabilistic socioeconomic projections, climate models, damage functions, and discounting methods that collectively reflect theoretically consistent valuation of risk, substantially increase estimates of the SC-CO2. Our preferred mean SC-CO2 estimate is $185 per tonne of CO2 ($44-$413 per tCO2: 5%-95% range, 2020 US dollars) at a near-term risk-free discount rate of 2%, a value 3.6 times higher than the US government's current value of $51 per tCO2. Our estimates incorporate updated scientific understanding throughout all components of SC-CO2 estimation in the new open-source Greenhouse Gas Impact Value Estimator (GIVE) model, in a manner fully responsive to the near-term NASEM recommendations. Our higher SC-CO2 values, compared with estimates currently used in policy evaluation, substantially increase the estimated benefits of greenhouse gas mitigation and thereby increase the expected net benefits of more stringent climate policies.

Embedding nature-based solutions into the social cost of carbon

China, the world's largest CO₂ emitter, is making every effort to transition to a low-carbon economy and fulfill its part of a concerted global commitment to combating climate change. In tandem with decarbonizing energy and industries, feasible supplementary measures are urgently needed to help remove anthropogenic CO₂ from the atmosphere. A burgeoning literature has emphasized the CO₂ removal capability of land re-naturalization (such as afforestation and wetland restoration), thereby regarding cognate land-use conversions as Nature-based Solutions (NbS) and potential climate policy options. However, little empirical evidence exists concerning the effectiveness of different land re-naturalization pathways (such as converting wetlands to forests or agricultural lands to grasslands), and it also remains unclear how NbS alternatives (i.e., land-use conversions resulting in negative CO₂ emission) and non-NbS options (i.e., land-use conversions resulting in positive CO₂ emission) could affect the social cost of carbon (SCC), a conventional measurement for prescribing carbon mitigation approaches. This study aims to fill in this knowledge gap via embedding NbS into the dynamic integrated climate-economics (DICE) model to quantify their impacts on the SCC. Using the Pearl River Delta region (south China) as a case study for the temporal horizon during 2000-2020, we find that both positive and negative CO₂ fluxes have been brought by different natural/semi-natural land conversions, affecting the SCC correspondingly. A total of 7 out of 17 types of land-use conversions could be identified as feasible NbS interventions, including forest restoration, forest-to-wetland, grassland-to-forest, grassland-to-wetland, grassland-to-cropland, cropland-to-forest, and cropland-to-wetland conversions, which could reduce the SCC values (comparing 2020 base-year with 2000 base-year) by 0.0132, 0.0009, 0.0033, 0.0030, 0.0001, 0.0082, and 0.0001 (USD/tCO₂), respectively. While the SCC is mainly determined by energy and industrial structure, the overall effect of NbS is larger than the sum of land urbanization and non-NbS land-use conversions. Via embedding the real-world inter-dynamics of land-use conversions into the SCC quantification, this study presents a pioneer assessment of the impacts of NbS on the SCC in an integrated framework, sheds important insights into the effectiveness of NbS, and offers practical implications for policy-makers to devise comprehensive policies covering all feasible CO₂ abatement options.

The global temperature-related mortality impact of earlier decarbonization for the Australian health sector and economy: A modelling study

Background

Sustained elevated concentration of GHGs is predicted to increase global mortality. With the Australian health sector responsible for 7% of the nation’s GHG emissions, the benefits and costs of various decarbonisation trajectories are currently being investigated. To assist with this effort, we model the impact earlier decarbonisation has on temperature-related mortality.

Design

We used DICE-EMR, an Integrated Assessment Model with an endogenous mortality response, to simulate Australian GHG trajectories and estimate the temperature-related mortality impact of early decarbonisation. We modelled a linear decline of the Australian health sector’s and economy’s GHG annual emissions to net-zero targets of 2040 and 2050.

Main outcome measure

Deaths averted and monetary-equivalent welfare gain.

Results

Decarbonisation of the Australian health sector by 2050 and 2040 is projected to avert an estimated 69,000 and 77,000 global temperature-related deaths respectively in a Baseline global emissions scenario. Australian economy decarbonisation by 2050 and 2040 is projected to avert an estimated 988,000 and 1,101,000 global deaths respectively. Assuming a low discount rate and high global emissions trajectory, we estimate a monetary equivalent welfare gain of $151 billion if the Australian health sector decarbonises by 2040, only accounting for the benefits in reducing temperature-related mortality.

Conclusions

Earlier decarbonisation has a significant impact on temperature-related mortality. Many uncertainties exist and health impacts other than temperature-related mortality are not captured by this analysis. Nevertheless, such models can help communicate the health risk of climate change and improve climate policy decision making.

Health and sustainability co-benefits of eating behaviors: Towards a science of dietary eco-wellness

Two of the greatest challenges of our times - climate change and the linked epidemics of obesity, diabetes, and cardiovascular disease - are fueled in part by the over-consumption of carbon-intensive high calorie foodstuffs. Converging evidence from hundreds of studies has confirmed that transitioning from diets high in meat and dairy to largely plant-based diets not only is necessary for climate change mitigation but will also lead to substantive reductions in morbidity and mortality. Nevertheless, there are only the faintest beginnings of a robust science of behavioral eco-wellness, defined here as the study of how individual choices, behaviors, and habits impact both personal health and environmental sustainability. This paper focusses on the sub-field of dietary eco-wellness, which looks at health and sustainability impacts of food production, procurement, preparation, and consumption. To advance this crucial agenda, investigators will need to invent, develop, and assess approaches aimed at helping people transition towards healthier and more sustainable diets. In order to accurately and reliably assess appropriate outcomes, existing assessment methods will need to be refined, new techniques will need to be advanced, and all measurement methods will need to be validated. Local conditions will influence the effectiveness of various approaches, and so it is important that scientists and communities share their stories of success and challenge for others to learn from. This paper reviews emerging evidence from relevant studies in dozens of countries, suggesting next steps, potential pathways, and a framework for interpretation.

Quantifying the climate benefits of a virtual versus an in-person format for an international conference

BACKGROUND

Academic institutions across the globe routinely sponsor large conferences. During the COVID-19 pandemic, many conferences have used all- or partially virtual formats. The conversion of the 2021 Consortium of Universities for Global Health (CUGH) conference, originally planned in-person for Houston, TX USA to an all-virtual format provided an opportunity to quantify the climate-related impacts of in-person versus virtual conferences.

METHODS

From the 2021 CUGH conference registration data, we determined each registrant's distance from Houston. Using widely available, open-source formulas, we calculated the carbon footprint of each registrant's round-trip drive or flight had they traveled to Houston. We assumed that registrants traveling more than 300 miles would have flown, with the remainder traveling by automobile.

RESULTS

Of 1909 registrants, 1447 would have traveled less than 4000 miles, and 389 would have traveled more than 10,000 miles round trip. Total travel-related carbon emissions were estimated at 2436 metric tons of CO₂, equivalent to the conservation of 2994 acres of forest for a year.

CONCLUSIONS

Organizations can now readily quantify the climate cost of annual conferences. CUGH's annual international conference, when held in-person, contributes significantly to carbon emissions. With its focus on promoting global health equity, CUGH may play a lead role in understanding the pros and cons for planetary health of in-person versus virtual conferences. CUGH and other organizations could routinely measure and publish the climate costs of their annual conferences.

Impact of Environmental Quality on Health Outcomes in Saudi Arabia: Does Research and Development Matter?

Recent literature on the health impacts of CO₂ emissions suggests a variety of factors that may establish a more robust link. However, no previous study has explored the role of research and development (R&D) in explaining the nexus between CO₂ emissions and health outcomes. Using data for Saudi Arabia over the period 2000–2018, this paper investigates the ability of R&D (expenditures and environmentally related R&D) to reduce the incidence of emissions on population health outcomes, particularly infant mortality and life expectancy. We find (i) negative impacts of CO₂ emissions on health outcomes; (ii) R&D expenditures have a weak positive impact on health outcomes; (iii) additionally to their direct effects on health outcomes, R&D expenditures remarkably enhanced health outcomes through reducing per capita CO₂ emissions; (iv) R&D expenditures interact with CO₂ from electricity and heat production and from electricity and heat production to negatively influence health outcomes. Similarly, environmentally related R&D, measured by patents environmental-related technologies, interacts with per capita CO₂ emissions to negatively influence health outcomes. To address these negative impacts, we calculated the corresponding R&D thresholds. Policymakers in Saudi Arabia are therefore called to give more and more incentives for R&D to reduce emissions and then improve population health outcomes.

Feasibility of the Olympic marathon under climatic and socioeconomic change

There are concerns about the impact of climate change on Olympic Games, especially endurance events, such as marathons. In recent competitions, many marathon runners dropped out of their races due to extreme heat, and it is expected that more areas will be unable to host the Games due to climate change. Here, we show the feasibility of the Olympic marathon considering the variations in climate factors, socioeconomic conditions, and adaptation measures. The number of current possible host cities will decline by up to 27% worldwide by the late twenty-first century. Dozens of emerging cities, especially in Asia, will not be capable of hosting the marathon under the highest emission scenario. Moving the marathon from August to October and holding the Games in multiple cities in the country are effective measures, and they should be considered if we are to maintain the regional diversity of the Games.

Climate Change and Infections on the Move in North America

Climate change is increasingly recognized for its impacts on human health, including how biotic and abiotic factors are driving shifts in infectious disease. Changes in ecological conditions and processes due to temperature and precipitation fluctuations and intensified disturbance regimes are affecting infectious pathogen transmission, habitat, hosts, and the characteristics of pathogens themselves. Understanding the relationships between climate change and infectious diseases can help clinicians broaden the scope of differential diagnoses when interviewing, diagnosing, and treating patients presenting with infections lacking obvious agents or transmission pathways. Here, we highlight key examples of how the mechanisms of climate change affect infectious diseases associated with water, fire, land, insects, and human transmission pathways in the hope of expanding the analytical framework for infectious disease diagnoses. Increased awareness of these relationships can help prepare both clinical physicians and epidemiologists for continued impacts of climate change on infectious disease in the future.

Estimates of country level temperature-related mortality damage functions

Many studies project that climate change is expected to cause a significant number of excess deaths. Yet, in integrated assessment models that determine the social cost of carbon (SCC), human mortality impacts do not reflect the latest scientific understanding. We address this issue by estimating country-level mortality damage functions for temperature-related mortality with global spatial coverage. We rely on projections from the most comprehensive published study in the epidemiology literature of future temperature impacts on mortality (Gasparrini et al. in Lancet Planet Health 1:e360–e367, 2017), which estimated changes in heat- and cold-related mortality for 23 countries over the twenty-first century. We model variation in these mortality projections as a function of baseline climate, future temperature change, and income variables and then project future changes in mortality for every country. We find significant spatial heterogeneity in projected mortality impacts, with hotter and poorer places more adversely affected than colder and richer places. In the absence of income-based adaptation, the global mortality rate in 2080–2099 is expected to increase by 1.8% [95% CI 0.8–2.8%] under a lower-emissions RCP 4.5 scenario and by 6.2% [95% CI 2.5–10.0%] in the very high-emissions RCP 8.5 scenario relative to 2001–2020. When the reduced sensitivity to heat associated with rising incomes, such as greater ability to invest in air conditioning, is accounted for, the expected end-of-century increase in the global mortality rate is 1.1% [95% CI 0.4–1.9%] in RCP 4.5 and 4.2% [95% CI 1.8–6.7%] in RCP 8.5. In addition, we compare recent estimates of climate-change induced excess mortality from diarrheal disease, malaria and dengue fever in 2030 and 2050 with current estimates used in SCC calculations and show these are likely underestimated in current SCC estimates, but are also small compared to more direct temperature effects.