How is climate change set to exacerbate the triple burden of disease within lower income nations?

People | Human Health

By George Blake, Kingfisher Writer

Published October 18th, 2021

Despite negligible emissions, lower-middle income countries (LMIC) are typically more vulnerable to the health impacts of climate change. Many LMICs are in a state of economic transition and are subject to significant burdens of communicable and non-communicable disease, both of which will be exacerbated under climate change.

The impacts of climate change on human health are multi-faceted, varying greatly from region to region and going far beyond the commonly discussed direct effects of natural hazards. A robust evaluation of health risks associated with climate change requires one to consider a holistic picture with a consideration of the prevalence of communicable and non-communicable diseases (NCD), the latter being diseases that are not transmitted between humans.

Nepal is subject to this ‘triple burden of disease’ and due to its geographical diversity, represents many of the effects of climate change occurring across a range of LMICs. | S Keso / Flickr

The disease regime of any given country is largely dependent on economic conditions, most ‘developed’ countries are characterized by relatively minimal communicable (such as HIV, measles, hepatitis A/B/C) and nutrient deficient disease (such as scurvy, rickets, hypocalcemia) but higher burdens of non-communicable disease (such as stroke, heart disease, and cancer).

Opposingly, many low-to-middle income countries (LMIC) are in a state of transition, where the burden of communicable disease remains high, while economic development is increasing the prevalence of NCDs and injuries. Hence, many LMIC are subject to a ‘triple burden of disease’ of communicable disease, NCD, and injuries, all of which are likely to worsen under climate change.

Of particular concern is the impact of climate change on the spread and prevalence of various parasites and pathogens responsible for serious disease, with projected climatic changes expected to lengthen the transmission seasons of important vector-borne diseases and alter their geographic range.

Higher global temperatures are likely to facilitate range expansions in vector-borne diseases such as dengue fever, malaria, and communicable diarrhoeal diseases and encourage bacterial growth, with evidence already detailing the spread of malaria to regions of higher elevation within the Himalayas.

Flooding in Haiti following Hurricane Tomas, such events can result in sudden disease outbreaks | United Nations Photo / Flickr

Furthermore, while natural hazards, such as flooding, landslides, and wildfires, evidently cause unexpected direct morality, especially among LMICs with limited adaptive capacity and preparedness, they also lead to clustered disease outbreaks and can compound existing health issues associated with water, sanitation, and hygiene (WASH) infrastructure. Such events are set to occur more frequently and less predictably in space and time under climate change.

Climate change also affects environmental determinants of health, such as air quality, safe drinking water, and food security. Around two-thirds of the global population are already subject to water scarcity for at least one month of the year, with climate change likely to further exacerbate water scarcity.

Beyond water availability, climate may also undermine water quality, which is heavily dependent on numerous climatic parameters including rainfall and temperature. Evidence suggests outbreaks of waterborne disease disproportionately occur in response to heavy rainfall events, with such events projected to increase in frequency.

Although all countries will be subject to increased injury and potential mortality associated with natural hazards, changes in communicable disease prevalence will mainly impact LMICs. Furthermore, demographic and lifestyle changes among many LMICs are increasing NCDs, such as cancer and chronic respiratory or cardiovascular disease, as the burden of communicable disease grows.

A mother weighs her child at a health centre in Ethiopia. Malnutrition already accounts for 45% of deaths among children under five. | UNICEF Ethiopia / Flickr

Climate change also further increases the burden of NCDs, with higher temperatures and changing climatic conditions linked to acute respiratory and cardiovascular disease, as well as cancer. Big questions also center around food security under climate change, with any reductions in yield, quality, or affordability likely to lead to malnutrition and chronic disease.

This triple burden of communicable, NCD, and injuries is likely to lead to significant mortality with LMICs. The World Health Organisation (WHO) estimates that between 2030 and 2050, climate change will result in roughly 250,000 additional deaths globally per year; 38,000 due to heat exposure in elderly people, 48,000 due to diarrhoea, 60,000 due to malaria, and 95,000 due to childhood undernutrition. The vast majority of these deaths are projected to occur in economically ‘developing’ countries.

These figures also do not account for premature deaths related to air pollution, which is thought to cause roughly nine million deaths annually. Beyond mortality, climate change is projected to result in direct health costs (excluding costs in health-determining sectors such as agriculture and sanitation) of between two and four billion USD annually by 2030.

Hence, in the run-up to COP26, scientists, professionals, and health organizations are urging world leaders to consider the health benefits of climate actions, especially within LMICs. Although many solutions to address climate change have numerous health co-benefits, there is still a need to ensure climate initiatives are explicitly designed to also deliver health benefits. Efforts must also be made to increase the resilience of healthcare facilities under climate change and to reduce emissions (4% to 5% of global total) associated with health care.

Even climate friendly measures like improving cycling infrastructure will have significant impacts on healthl; if England were to match levels of walking and cycling seen in Copenhagen, the NHS would save £17 billion over 20 years. | M Waterford / Flickr

Given the amplified interest in human disease following the onset of the pandemic, there is clear scope for health to form a central pillar of COP26 negotiations and ‘green’ recoveries. The increased attention on the health costs of climate change further strengthens the argument for early and decisive measures. Although there is still a need for a more holistic approach when it comes to health.

Additive impacts of climate changes on existing disease burdens with LMICs remain largely overlooked, despite the potential of substantial instability and economic losses within these countries. This triple burden of disease represents a plausible barrier to development and requires effective, proactive, and integrated health and climate policy. Given the limited culpability of LMIC in climate change, the failure of richer countries to initiate the urgent measures required would represent a serious moral failure.

Featured Image: UNAMID | Flickr

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