Scientists have said increasingly hot weather is responsible for an average of almost 50,000 years of healthy life lost to cardiovascular disease every year among people in Australia.
The figure equates to around 7.3% of the total burden due to illness and death from cardiovascular disease, with the team warning that this figure could double, or even triple, by the middle of the century, if we continue with the current trend of greenhouse gas emissions.
The research was led by Peng Bi, professor of Public Health and Environmental Medicine at the University of Adelaide, Australia. He said: “When the weather is hot, our hearts have to work harder to help us cool down. This added pressure can be dangerous, especially for people with cardiovascular disease.
“Many of us have experienced how a warming climate can make us feel unwell, particularly during longer periods of extreme heat. However, it’s still not clear exactly how many people are living with serious heart disease or dying early because of higher temperatures, and we need to understand how this burden will increase in the future.”
The authors of the study added since the risk of cardiovascular disease increases with higher temperatures, their findings are also relevant to people around the world.
To calculate the current impact of high temperatures, the researchers used data from the Australian Burden of Disease Database on illness or death caused by cardiovascular disease between 2003 and 2018. Then they used a statistical model to calculate how much cardiovascular disease or death can be attributed to hot weather in different parts of Australia and the country as a whole.
This showed that there was an average of 49,483 years of healthy life lost annually to cardiovascular disease caused by hot weather. Most of these years were lost due to death, rather than illness.
The researchers then used their model to look at the likely impact of climate change driven by greenhouse gas emissions in the future. They used two of the climate change scenarios outlined by the Intergovernmental Panel on Climate Change: a scenario where emissions stabilise (Representative Concentration Pathway 4.5 or RCP4.5) and a scenario with continually rising emissions (RCP8.5).
They also looked at the impact of population growth and how people might adapt to cope with higher temperatures.
The model shows that by 2030, the number of DALYs lost due to cardiovascular disease caused by hot weather will increase by 83.5%, reaching 90,779.7 DALYs, under the RCP4.5 scenario. By 2050, this number is expected to rise further to 139,828.9 DALYs, a 182.6% increase. Under the more severe RCP8.5 scenario, the DALYs are projected to increase by 92.7% to 95,343.0 DALYs in 2030 and by 225.6% to 161,095.1 in 2050.
Bi said: “This study combines several key factors – climate change, population shifts, and adaptation strategies – to give a full picture of the disease burden across Australia. This makes our study one of the first of its kind globally. Predicting future disease burden always comes with some uncertainty, and our models rely on assumptions that may not capture every real-life detail. However, despite these uncertainties, the comprehensive nature of our approach makes the study especially valuable for planning future climate change adaptation and mitigation strategies.
“Although our study is focused on Australia, the fundamental link between higher temperatures and increased cardiovascular risk has been documented globally. While the specific risks may vary depending on local climates, population demographics and levels of adaptation, the overall trend – that higher temperatures lead to more cardiovascular disease burden – is likely relevant in many parts of the world.”
Bi continued: “Our research shows that as climate change brings more frequent and intense heat, the risks associated with higher temperatures are likely to increase, especially for vulnerable groups. It highlights the importance of taking precautions during hot weather, such as staying hydrated, finding cool environments and seeking medical help when needed.
“Our findings also call for urgent investment in adaptation and mitigation strategies, including urban cooling plans, public health campaigns and improved emergency responses during hot weather.”
The study comes after a team from Imperial College London and Johns Hopkins University in the USA released research which predicts that most of the population of the continental United States will be at higher risk of airway inflammation by the latter half of this century, due to higher temperatures and drier air.
Researchers at Imperial College London teamed up with colleagues at Johns Hopkins University and the University of Carolina to find out how breathing dry air affects the mucous surfaces of human airways, including the mouth, nose, larynx, trachea and lungs.
Inflammation of the airways can cause or exacerbate conditions like asthma, chronic bronchitis, allergic rhinitis and chronic cough, and will potentially exacerbate lung diseases. The researchers say that human mucosa dehydration presents a critical threat to human health.