When the climate threatens health: The Lancet Countdown report

No country – whether rich or poor – is immune from the health impacts of worsening climate change. Unless urgent action is taken, climate change will increasingly threaten global health, disrupt lives and livelihoods, and overwhelm healthcare systems, according to the 2020 Report of the Lancet Countdown on Health and Climate Change, recently published in The Lancet.

The authors say that the recovery from the COVID-19 pandemic offers a key moment to act on climate change. Together, a joint response to converging crises offers the chance to improve public health, create a sustainable economy, and protect the environment.

Health threatened on a global scale

“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,” says Dr Ian Hamilton, executive director of the Lancet Countdown. “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. This year’s devastating US wildfires and tropical storms in the Caribbean and Pacific, coinciding with the pandemic, have tragically illustrated that the world doesn’t have the luxury of dealing with one crisis at a time.”

New evidence from the Countdown report shows that the last two decades have seen a 54% increase in heat-related deaths in older people, with a record 2.9 billion additional days of heatwave exposure affecting over-65s in 2019 – almost twice the previous high.

However, the 120 world-leading health and climate change academics and clinicians behind the new report say that if we take urgent action to tackle climate change – by implementing plans to deliver commitments of limiting global temperature increases to well below 2 °C – we can mitigate these shocks and achieve health and economic benefits instead. At the same time, these actions could reduce the risk of future pandemics because the drivers of climate change can also drive zoonotic pandemic risk, caused by infectious diseases that jump animals to humans.

The 5th anniversary of the Paris Agreement

The report –a collaboration between experts from more than 35 institutions including the World Health Organization (WHO), World Meteorological Organization, led by University College London – publishes on the 5th anniversary of the Paris Agreement, when the world pledged to limit global warming to well below 2 °C.

Dr Wenjia Cai, director of the newly-launched Lancet Countdown Regional Centre for Asia, based within Tsinghua University in Beijing, China, said: “On the occasion of the 5th anniversary of the Paris Agreement, we must confront the worst outlook for public health our generation has seen. Failure to meet our climate commitments could take some key Sustainable Development Goals out of reach as well as our ability to limit warming.”

Climate-related health shocks globally and across Europe

From small islands to big cities, climate-related health shocks may arise in the future due to difficulties anticipating the impacts of extreme heat and finding successful ways to adapt.

Impacts of this include growing levels of heat-related mortality among vulnerable people in all parts of the world, with 296,000 lives claimed in 2018. Livelihoods are at risk too as heat is increasingly affecting people’s ability to work outdoors in developing regions, with significant economic implications. Last year saw a continued loss in productivity, with India accounting for 40% of the total 302 billion work hours lost.

Europe, with its ageing city-dominated population, has the highest score of any region, at 41%, on the report’s heat vulnerability index, which combines heatwave exposure with data on population susceptibility and the ability of health systems to cope. It also accounts for more than a third of heat-related mortality in the elderly with 104,000 out of 296,000 deaths globally in 2018.

The region also suffered the greatest economic fallout from these deaths with costs equal to the average income of 11 million citizens or 1.2% of Gross National Income. The highest costs were observed in Germany, where they were equivalent to the average income of 1.75m citizens.

A sharp increase in exposure to wildfires

Heat and drought are also driving sharp increases in exposure to wildfires, resulting in burns, heart and lung damage from smoke, and the displacement of communities. Some 128 countries have experienced an increase in population exposure to wildfires since the early 2000s, with the USA seeing one of the largest increases. By the end of the century, meanwhile, the report finds that projected sea level rise could threaten the displacement of up to 565 million people, exposing them to a wide range of health harms.

Professor Hugh Montgomery, Lancet Countdown co-chair and an intensive care doctor, based at University College London, said: “Climate change drives a cruel wedge which widens existing health inequalities between and within countries. Our report shows that – just as for Covid-19 – older people are particularly vulnerable, and those with a range of pre-existing conditions including asthma and diabetes are at even greater risk.”


Half of countries have drawn up national health and climate plans

New data in the report highlight that healthcare capacity to deal with these future health shocks is still not enough, despite improvements. Only half of countries surveyed have drawn up national health and climate plans, with just four reporting adequate national funding, and less than half of countries have conducted vulnerability and adaptation assessments for health. Meanwhile, two thirds of global cities surveyed expect climate change to seriously compromise public health infrastructure.

Professor Hugh Montgomery added “The COVID-19 pandemic has thrown a spotlight on the current ability of healthcare and wider health systems to cope with the sorts of future health shocks that climate change may generate. Flames, floods and famine do not respect national borders or bank accounts: a nation’s wealth offers no protection against the health impacts of even a 1.2C global average temperature rise.”

Pandemic and climate crises

A Lancet editorial, published alongside the new report, highlights that climate change and zoonotic pandemic risk share common drivers, making them inextricably entwined so that they must be handled together. Climate change and its drivers damage the environment through urbanization, intensive agriculture and unsustainable food systems, air travel and tourism, trade, and lifestyles powered by fossil fuels, in turn creating conditions that encourage zoonoses.

Dr Richard Horton, editor-in-chief of The Lancet, said: “If we wish to reduce the risk of future pandemics, we must prioritise action on the climate crisis – one of the most powerful forces driving zoonoses today. Now is the time for us all to take the environmental determinants of health more seriously – we must address the climate emergency, protect biodiversity, and strengthen the natural systems on which our civilisation depends. This is a moment we cannot afford to ignore. Just as we have seen with COVID-19, delayed action will cause avoidable deaths.”

The new Lancet Countdown report explains that climate change is leading to more favorable conditions for the spread of deadly infectious diseases such as dengue fever, malaria, and vibriosis – putting at risk the decades of progress in tackling these diseases.

Since 1950, the suitability for malaria transmission in highland areas was 39% higher in the WHO African region.

Seven million annual deaths from air pollution

By limiting temperature increases to well below 2 °C, and aligning climate and pandemic recovery, the world can deliver near-term and long-term health benefits, according to the new report. Health gains could in turn deliver many billions in economic benefit, which could more than pay for the costs of mitigation and bolster the case for green stimulus measures.

The seven million annual deaths from air pollution associated with the combustion of fossil fuels point to the potential. With fossil-fueled transport systems still dominating urban areas, some 40 million people in the 115 largest EU cities are exposed to pollution levels exceeding WHO guidelines. In the WHO Europe region modest steps to promote cleaner energy and transport sectors saw deaths from ambient PM 2.5 air pollution fall from 62 per 100,000 in 2015 to 59 per 100,000 in 2018. Globally, deaths from ambient PM 2.5 associated with coal fell by 50,000 in the same year.

Health gains could in turn deliver many billions in economic benefit, which could more than pay for the costs of mitigation and bolster the case for green stimulus measures. For example, the European Union’s marginal air quality improvements from 2015 to 2018, could be worth an estimated US$ 8.8bn every year, if held constant. Stemming from the annual average reduction in years of life lost, the figure will grow with further improvements in air quality.

2.3 million annual deaths are attributable to diet related risk factors


Given that food production is the source of a quarter of the world’s GHG emissions, the report suggests there is a similar opportunity to address some of the 9 million annual deaths linked to poor diet. With livestock being particularly emissions-intensive, the report examined deaths from excess red meat eating. The authors found that mortality has risen 70% over the last 30 years, with the majority of the now almost 1 million annual deaths occurring in the regions of the Western Pacific and Europe.

In Europe 2.3 million annual deaths are attributable to diet related risk factors, of which almost 307,000, are due to excess red meat consumption.

Dr Maria Neira, director of the Department of Environment, Climate Change and Health at the World Health Organization, said: “With trillions being invested globally in economic support and stimulus there is a genuine opportunity to align the responses to the pandemic and climate change to deliver a triple win – one that improves public health, creates a sustainable economy and protects the environment. But time is short. Failure to tackle these converging crises in tandem will lock in huge amounts of fossil fuels, moving the world’s 1.5C target out of reach and condemning the world to a future of climate-induced health shocks.”


This post is also available in: Chinese (Simplified)

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