Global Warming Increasing Heat-Related Death, Disease Risk: Study

Rising vulnerability to heat-related risks of climate change is mirrored by increased exposure to high temperatures.

Climate change is putting an increasing proportion of the global population at risk of heat-related death and diseases, and causing significant loss of work hours in vulnerable areas like India, sub-Saharan Africa, and South America, according to a study published in The Lancet journal.

The rising vulnerability to the heat-related risks of climate change is mirrored by increased exposure to higher temperatures. Despite a mean global temperature increase of 0.3 degrees Celsius between 1986 and 2017, the average temperature increase people were exposed to was more than double this (0.8 degrees Celsius).

With the pace of climate change outweighing the urgency of the response, the report provides cause for concern.

However, researchers also note promising trends in key areas for health, including the phase-out of coal, the deployment of healthier, cleaner modes of transport, and health system adaptation.

Present day changes in heat waves and labour capacity provide early warning of the compounded and overwhelming impact on public health that is expected if temperatures continue to rise. Trends in the impacts of climate change, exposures and vulnerabilities show unacceptably high risk for health now and in the future.

Hilary Graham, The University of York, UK

“The lack of progress in reducing emissions and building adaptive capacity threatens lives and health systems and must be addressed to avoid disruption to core public health infrastructure and overwhelming health services,” she added.

Despite delays, some sectors are embarking on a low-carbon transition, which is a promising sign. It is clear that the nature and scale of the response to climate change will be the determining factor in shaping the health of nations for centuries to come.

Hilary Graham

The annual report tracks 41 indicators across five areas: climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; finance and economics; and public and political engagement.

The indicators include weather-related disasters, food security, clean fuel use, meat consumption, air pollution and the number of scientific research articles about climate and health.

As a result of increasing temperatures caused by climate change, vulnerable populations (adults over 65 years old, people living in cities, and people with cardiovascular diseases, diabetes, and chronic respiratory diseases) are exposed to heat stress, increasing their risk of cardiovascular disease, and kidney disease.

In 2017, over 157 million vulnerable people over the age of 65 were exposed to heatwaves, and 18 million more people compared to 2016.

Europe and the eastern Mediterranean are more vulnerable than Africa and southeast Asia, most likely due to ageing populations living in cities - 42 per cent of Europeans and 43 per cent of people in the eastern Mediterranean are aged over 65 and vulnerable to heat exposure, compared with 38 per cent in Africa and 34 per cent in southeast Asia.

However, as the prevalence of NCDs increases in low- and middle-income countries, the vulnerability of these populations also increases -particularly in southeast Asia where vulnerability to heat exposure has increased by 3.5 per cent since 1990.

On average, each person was exposed to an additional 1.4 days of heatwave from 2000 to 2017, compared with 1986-2005.

Rising temperatures are a risk in occupational health, and as temperatures regularly increase above physiological limits, sustained work becomes more difficult or impossible.

In 2017, 153 billion hours of labour were lost due to heat exposure, an increase of 62 billion hours relative to 2000. In addition, these changes were concentrated in already vulnerable areas in India, southeast Asia, and sub-Saharan Africa, and South America.

Around 80 per cent of these losses were in the agricultural sector (122 billion hours lost), 17.5 per cent were in the industry sector (27 billion), and 2.5 per cent were in the service sector (4 billion).

Vulnerability to extreme heat has steadily increased around the world since 1990. This has led to vast losses for national economies and household budgets. At a time when national health budgets and health services face a growing epidemic of lifestyle diseases, continued delay in unlocking the potential health benefits of climate change mitigation is short-sighted and damaging for human health. 

Joacim Rocklov, Umea University, Sweden