In December 2019, JPA published an editorial considering the convergence of climate change with population ageing (Harper, 2019). The subsequent Covid-19 pandemic turned the world’s attention away from climate change for several months. JPA is now returning to the debate on older persons and climate change, with the publication of a Special Issue on The Implications of Climate Change for the Health of Older Adults. We are thus calling for submissions to this issue, further details are available on the Springer JPA website and on the website of the Oxford Institute of Population Ageing.

As the February 2022 report from the IPCC stated, current trends predict a definite rise of more than 1.5°C. This constitutes a “critical level” beyond which the impacts of the climate crisis accelerate strongly and some become irreversible. Everywhere on earth is now affected, with no inhabited region escaping impacts from rising temperatures and increasingly extreme weather. In addition, some three and a half million people, around half the entire global population, now live in areas “highly vulnerable” to climate change. Millions of people face food and water shortages owing to climate change, and coastal areas around the globe, and small, low-lying islands, confront inundation.

The Lancet Countdown 2021 vividly describes the situation:

The world is now 1·2 °C warmer than in the pre-industrial period (1850–1900), the past 7 years have been the hottest 7 years on record, and 2020 tied with 2016 as the hottest year yet. Atmospheric CO2 concentrations have reached a concerning milestone and are now 50% higher than in the pre-industrial era. Changes, such as reduced soil moisture, could limit the Earth’s carbon reuptake, resulting in increased CO2 concentrations in the atmosphere.20 Furthermore, some critical tipping points are close or might have been surpassed, which could destabilise the Earth’s climate system. Although the large reductions in transport use and industrial manufacturing during the pandemic resulted in energy-related emissions for 2020 falling by 5·8% (the largest annual percentage decline since World War 2), this reduction was short-lived and emissions have risen in 2021. Without an adequate response, the health effects of climate change will worsen throughout the coming decades (Romanello et al., 2021).

The WHO, 2017 listed the health hazards for human health due to climatic changes into the following items: (1) direct and indirect effects of global warming, (2) stratospheric ozone depletion, (3) disturbance in terrestrial and marine ecosystems, (4) loss of biodiversity, (5) changes in the hydrological systems and freshwater supply, (6) Land degradation and loss of river deltas and coastal cities, (7) urbanization, deforestation and population dislocation/immigration, and finally (8) limited food production (WHO, 2017).

There is now considerable evidence that climate change and increased climate variability are having both direct and indirect effects. Direct effects of environmental changes have a particular impact on the health of older adults such as extreme weather events - heat and cold waves, and natural disasters. Indirect environmental effects such as polluted air and water; ecosystem effects such as the environmental conditions which are advantageous for the transmission of water-borne, airborne, food-borne, and vector-borne pathogens, and for species which are carriers of disease and destruction; and socio-economic effects such as water and food dislocation and competition.

There is now robust evidence that both these direct and indirect effects may lead to rising morbidity and mortality arising from chronic diseases, infectious and water-borne diseases, malnutrition, and mental health problems. We also know that older adults face higher risks from climate change compared to the rest of the population. In particular, older adults are vulnerable to being trapped both in poor environments and after extreme events such as flooding or drought, through lack of income, mobility, disability or frailty. They are at increased risk of both heat-related and cold related illnesses, compounded by living alone, co-morbidities, and medication. They are at higher risk of dehydration than young people, due to the physiological changes that occur as part of the ageing process, and particular vulnerable to viral and bacterial diseases.

In general, it can be said that the impact of these effects on the health of older populations vary in their impact, timing and durability. So that extreme events such as heat waves tend to lead to immediate cardiovascular events, while cold waves often result in delayed respiratory diseases. Extreme water events, such as flooding lead to mortality by drowning, but may result in higher levels of resilience, while drought is associated with longer term mal and under-nutrition, mental illness, and the exacerbation of underlying chronic diseases.

Even mild dehydration of older people adversely affects mental performance and memory, leading to weakness, dizziness and increased risk of falls, while acute dehydration leads to loss of kidney function and cardiac function. Consequently, any reduction in access to fresh water, during a drought for example, has severe implications for older adults. Indirect effects such as increased air pollution and reduced air-quality are associated with the incidence of chronic obstructive pulmonary disease (COPD), chronic bronchitis (CB), asthma, and emphysema; contaminated water leads to diarrheal diseases such dysentery, Hepatitis E, cholera and typhoid which are frequently fatal in older people.

In addition, the low nourishment from the poor diets during a drought compounds the impact and long term implications for health. In LMICs older people have a high exposure to food insecurity and a lack of access to resources for food production. They often consume low nutrient foods and contaminated foods, leading to high levels of exposure to disease and death from contamination. There is also now evidence for malnutrition among older people in many high income countries. Even mild reduction in nutrients for older adults arising from food depletion and famine has the longer term impact of increases in diabetes, heart disease, depression, falls and frailty.

The emergence over the past decade of climate gerontology (Haq & Gutman, 2014) has identified a wide range of climate change impacts on the health of older adults (Leyva, Beaman, & Davidson, 2017). However, it should be noted that this evidence while robust in its methods and findings, has tended to be biased by the questions it to focuses on and the associations it examines. For example, over one fifth of the studies of the impact of climate change on older adult health focused on mortality from cardiovascular diseases. 10% looked at death from respiratory disease and 10% mental health challenges (Ayalon et al., 2021). Few analysed data on issues such as drowning due to flooding, vector-borne diseases arising from environmental change, impact on nutrition, or declining overall health arising from long term climate changes.

While as a percentage of the population, more younger than older people live in coastal cities, the numbers and percentages of older people are increasing. Older adults will be affected by an inability to make the long-term migratory moves to escape the double impact of heat and flooding in these zones. While few studies have assessed older populations specifically in terms of increased pollution, most have shown higher risks in the older adults compared to the rest of the population. This appears due to long term exposure, comorbidities and frailty increase cumulative associations between air pollution and lung function. Research has shown that older people face particular challenges during humanitarian crises bought on by climate events, including difficulty in accessing distant relief and service points. In addition most disaster response programmes lack explicit focus on older people, compounded by the view that families will provide for older members. Older populations are therefore likely to continue to be at higher risk and vulnerability with lower levels of resilience.

These environmental changes are occurring in the context of a world order which is becoming more fragile and unpredictable. The once viewed unstoppable linear progression towards greater democracy of the 1990s, with more open markets and peaceful international cooperation, appears to be weakening. The Covid-19 Pandemic of the early 2020’s reveals global vulnerability to disease. The Ukrainian invasion by Russia early in 2022 has questioned global political frameworks and security in operation for the previous 30 years. Globalisation may well be driven by a new set of powers, within a new framework of understandings and values. The nature of globalisation will change, with the rise of Asia operating within different paradigms. The challenges of climate change and access to changing environmental resources will place increasing pressure on a multilateral framework developed under very different conditions. States such as Russia, North Korea and some in the Middle East, will be joined by no-state players, many fuelled by religious and cultural extremism, to act as disrupters to the accepted rules of international co-operation. Both the Covid-19 pandemic and the Russian invasion of Ukraine have highlighted this. The potential for increased global inequality and a reduced global ability to tackle climate change will only increase the future impact on the world’s older population, one of the earth’s most vulnerable populations.

We look forward to contributing to this important discussion and development of evidence through the publication of a Special JPA Issue on The Implications of Climate Change for the Health of Older Adults.