Climate activists take part in a rally to create awareness about global warming in New York. (File)

Jonathan Ashworth, The Independent

The ethical case for combatting climate change is incontestable, the economic one, indisputable. I would argue that the health case for achieving our climate goals is equally strong.

It seems the WHO agree. In advance of Cop26, it released a special report emphasising the need to ensure that health is at the forefront of the climate change agenda. It’s very clear why.

Between 2030 and 2050, climate change is expected to cause approximately 250,000 additional deaths per year worldwide.

Flooding resulting from extreme weather events and rising sea levels brings with it water-borne diseases and takes a huge toll on the mental health of those affected.

Extreme heat causes dehydration, heat stroke and exacerbates cardiovascular disease.Air pollution has been linked to cancer, neurological conditions including dementia, and increased susceptibility to asthma and respiratory diseases.

And human destruction of the natural world heightens the threat of future pandemics.

Every minute, forests the size of 35 football pitches are destroyed. Less than 10 per cent of the earth’s land surface can now be said to be “natural” and since 1970, the majority of the world’s wild land animals have been wiped out.

The dramatic loss of host species has forced many parasites to look for alternative hosts - either livestock or humans. Deforestation and intensive agriculture are also leading to increased contact between humans and animals, making it easier for pathogens to pass between them, causing disease “spillover” events. Rising temperatures and annual rainfall resulting from climate change is also widening the distribution of disease carrying animals such as malarial mosquitoes, and increased urbanisation and international travel serve only to accelerate the pace at which infections can spread.

Now, 75 per cent of emerging infections in human populations have come from animals and future outbreaks of new diseases are likely. Viruses even more deadly or contagious than Covid-19 could make the jump.

Biodiversity loss also undermines food security and destroys the habitat of plant life harbouring undiscovered medicines.Here in the UK, it is very clear that we are vulnerable to the effects of the climate crisis. For every 1°C increase in temperature over 20°C, ambulance call outs for the NHS increase by 1 per cent. The 2020 heatwaves in the UK were estimated to have led to more than 2,500 deaths. Deaths due to extreme heat are projected to double by the 2050s.

1.8 million people in Britain are living in areas at significant risk of flooding; air pollution causes 40,000 deaths a year.

Evidently, climate change needs to be tackled as a priority, with the same urgency as the response to the Covid-19. Continued negligence puts us all in danger.

To guard against the next pandemic, we should be taking a government-wide “health in all policies” approach, with properly funded public health services to improve population health and tackle growing inequalities. Buttressing this by undertaking regular pandemic planning and leading the way on global disease surveillance and R&D will ensure we are prepared.

Not only will we need a health system that is resilient in the face of the growing challenge of climate change, we need one that is actively part of the solution. The NHS currently contributes 4 per cent of the UK’s total greenhouse gas emissions. Globally, if healthcare were a country, it would be the fifth largest emitter on the planet.

I welcome NHS England’s pledge to reach net zero by 2040. But achieving a green recovery from COVID is not just about building a few new hospitals in a carbon neutral way, while existing infrastructure is left crumbling with a £9.2bn repair backlog.

Sustainability must become central to every aspect of how the system operates, from service delivery to energy consumption. NHS staff, who are continually asked to do ever more with even less, must be fully involved to make sure the changes work for them.

Even just by planting trees across the NHS estate, we can capture carbon and improve the surroundings for patients and staff. Instead, the Conservatives have missed tree-planting targets by over 50 per cent and one in seven native British species is now at risk of extinction.

As well as setting an example here at home, we have a duty to reach beyond our own shores and protect the world’s most vulnerable. They will likely be hit hardest by the climate crisis. But the government’s decision to cut overseas aid will have a disastrous effect on many countries on the frontline of the climate emergency, which are among the world’s poorest. It undermines our role as hosts of Cop26, as well as our international standing and moral authority.