GLASGOW (THOMSON REUTERS FOUNDATION) - From extreme heat to worsening hunger and water shortages, accelerating climate change threatens "unimaginable" health consequences, scientists and health officials warned on Saturday (Nov 6) on the sidelines of the COP26 UN climate talks in Glasgow.

As with the Covid-19 pandemic, "it won't be long before the entire population of the world is affected, directly or indirectly," said former Australian prime minister Julia Gillard, now head of British health charity the Wellcome Trust.

But a big menu of possible changes - from making cycling and walking easier in cities to altering diets and ramping up renewable energy - could together curb warming, protect health and make life better for billions of people, experts said.

Making those shifts happen will require not just investment and efforts to make the health benefits clearer but also, crucially, bringing on board people who do not normally work on health issues.

With huge influence on air pollution and how people choose to travel, for instance, "the minister of transport is probably more a minister of health than the minister of health", noted Richard Smith, president of the UK Health Alliance on Climate Change.

Too often efforts to cut emissions, adapt to climate threats and deal with health problems are carried out separately, but "we need these people to work together for integrated solutions", said Andy Haines of the London School of Hygiene and Tropical Medicine.

Doing so might include things like adding more trees and water-absorbing green areas in poor areas of cities, to address inequity, flooding and heat risks at once, while also boosting nature and improving mental health.

"The solutions are the same for the climate, our health and biodiversity," said Rayan Kassem, West Asia regional director for Youth4Nature, a green non-profit focused on climate and nature solutions.

Air pollution

Climate change is already driving diverse health threats around the world, said Haines, a professor of environmental change and public health.

For instance, the ranges of insect-carried diseases such as malaria and dengue are altering as weather patterns shift, and heat deaths are swiftly rising, with over a third of those recorded from 1990-2018 attributed to climate change, he said.

A rising toll of wildfires, floods, droughts and extreme heat is also having "really devastating effects" on mental health, alongside worries among many people about the future under worsening climate change, Haines said.

As permafrost melts in the fast-warming Arctic, he said, it could even expose "Methuselah organisms" - long frozen and potentially deadly bacteria and viruses.

"As we release these, we don't know what is going to happen to human health," he said.

But some health risks connected to climate change are already well known.

Air pollution, much of it connected to the use of fossil fuels, kills about seven million people a year, said Diarmid Campbell-Lendrum, who heads the World Health Organisation's climate and health unit.

A major step towards reducing that risk would be removing what the International Monetary Fund says are US$5.9 trillion (S$8 trillion) in direct and indirect subsidies to the fossil fuel industry each year, which makes polluting fuels artificially cheaper, he said.

"We need to stop spending money on the wrong things and start spending it on the right things," said Campbell-Lendrum, a keen cyclist who biked 1,600km to the Glasgow summit from Geneva.

Rosamund Adoo-Kissi-Debrah, whose nine-year-old daughter Ella died in London in 2013 of a severe asthma attack that coroners attributed to "excess air pollution", told conference participants that "breathing clean air is a human right".

The UN Human Rights Council in October passed a resolution for the first time recognising access to a healthy and sustainable environment as a universal right.

Poornima Prabhakaran, deputy director of the Centre for Environmental Health at the Public Health Foundation of India, said air pollution also had "huge social and economic costs" for her country, home to 15 of the world's 20 most polluted cities.

"This crisis is real," she said. "We do not want a cosmetic response... We want real and tangible action."

People already disadvantaged and least able to prepare for, respond to and recover from climate change impacts will be hurt worst, warned Susan Aitken, leader of the Glasgow City Council.

"That's as true here in a city like Glasgow as it is on a global scale," she said.

Greener health service for Britain?

As they seek ways to limit growing health threats, doctors and hospitals are also looking at ways to cut their own emissions.

Nick Watts, chief sustainability officer for Britain's National Health Service (NHS), said the US$120-billion-a-year service accounted for roughly 5 per cent of UK greenhouse gas emissions - or about the same as a country like Denmark or Croatia.

To help meet Britain's goal of cutting its emissions 78 per cent by 2035, the service has set an initial one-year goal to eliminate emissions equivalent to those used to power 1.1 million homes in the country annually.

That involves things like making buildings more energy-efficient, asking suppliers to match the NHS' net-zero goals and cutting transport emissions from the service itself and its users through changes like more online appointments.

The NHS' first zero-emissions ambulance, being trialled in Birmingham, also is parked at the COP26 venue in Glasgow.

"This is going to be the future of healthcare in this country and everywhere else," Watts said at the conference.

Jeni Miller, executive director of the Global Climate and Health Alliance, emphasised that many more national climate plans need to take into account health threats - and that cutting emissions will be key to curbing those risks.

"The decisions made at COP26 will define the health and well-being of people... for years to come," she said.