Deaths from heat among older people have more than doubled in the UK since the early 2000s, as the effects of climate change on health worsen, a report has warned.

The Lancet Countdown’s fifth annual report tracking the links between climate change and health warns that no country, rich or poor, is immune from the impacts of rising temperatures.

The assessment of more than 40 global indicators measuring the impact of the changing climate warned that, without urgent action, it will increasingly threaten health, disrupt lives and overwhelm health services.

But action which helps cut the emissions driving rising temperatures, such as reducing excess red meat consumption and reducing the sources of air pollution such as coal plants and traffic, can benefit health.

The report, published in The Lancet, is a collaboration between experts from more than 35 institutions, including the World Health Organisation (WHO) and World Bank, and led by University College London.

Heatwaves are one of the major health impacts of climate change, causing deaths and illness from heat stress and heat stroke and worsening heart and breathing diseases, with the over-65s among the most vulnerable, it warns.

Because of its ageing and largely urban population and levels of chronic disease, the UK has one of the highest levels of vulnerability to the health effects of heat in the world.

There were an estimated 8,500 heat-related deaths among the over-65s in the UK in 2018, more than double the average for 2000-04, with growing numbers of older people increasingly exposed to heatwaves.

The UK also experienced 5.6 million hours of potential lost work in 2019 due to heatwaves, the report said.

Across the world, heat-related deaths of vulnerable people have increased by 54% in the last two decades, claiming 296,000 lives in 2018, while hot conditions are also affecting people’s ability to work outside in many places.

Wildfires, a lack of green space to help reduce hot conditions in cities, displacement due to flooding, and threats to food security are all among the increasing climate impacts which affect health, the report said.

But aligning climate action and the recovery from the pandemic by investing in a shift to clean energy and transport could help the world deliver immediate and long-term health benefits.

That includes cutting combustion of fossil fuels, from coal-fired power plants to home heating systems, industry and vehicles, which contribute to seven million deaths a year worldwide from air pollution.

In the UK, there were an estimated 17,700 deaths linked to ambient fine particulate air pollution, known as PM2.5, from human activities in 2018, from sources including households, agriculture, transport, and power plants.

The report said the food system is responsible for 20%-30% of global greenhouse gas emissions, most of which come from meat and dairy livestock.

At the same time, excess red meat-eating has a growing impact worldwide and was linked to almost a million premature deaths in 2017.

In the UK, red meat eating accounted for 12,270 deaths in 2017 out of a total of nearly 116,000 deaths attributable to diet-related risk factor, the experts said.

Reducing reliance on red meat consumption and prioritising healthier alternatives – with choices available depending on the region, individual and cultural context – as part of a range of measures in the food system could help tackle climate change, the report said.

Dr Ian Hamilton, executive director of the Lancet Countdown, said: “The pandemic has shown us that when health is threatened on a global scale, our economies and ways of life can come to a standstill.

“The threats to human health are multiplying and intensifying due to climate change and, unless we change course, our healthcare systems are at risk of being overwhelmed in the future.”

An editorial published alongside the report in the Lancet said curbing the drivers of climate change such as intensive farming and encroaching into wild areas such as forests would help stop future pandemics which arise in animals from emerging.