It said that the global land area affected by extreme drought had increased by nearly a third in the last 50 years, putting hundreds of millions of people at risk of water insecurity.

“Climate change is already having a negative impact on food security, with worrying implications for malnutrition and under-nourishment,” said Elizabeth Robinson, director of the Grantham Research Institute at the London School of Economics and a lead contributor to the Countdown.

“Further increases in temperature, frequency and intensity of extreme weather events, and carbon dioxide concentrations, will put yet more pressure on availability of and access to nutritious food, especially for the most vulnerable.”

Robinson said supply shocks triggered by Russia’s invasion of Ukraine in February highlighted the world’s susceptibility to food chain disruptions.

‘Deep failure’

The assessment showed that heat-related deaths increased by 68 per cent between 2017-2021 compared to 2000-2004, and human exposure to days of high fire risk rose 61 per cent over similar time periods.

Climate change is also affecting the spread of infectious diseases, the report showed.

For example, the length of time suitable for malaria transmission rose by almost a third (32.1 per cent) in some parts of the Americas, and 14.0 per cent in Africa over the past decade, compared to 1951-1960.

Furthermore, the Countdown showed how governments are themselves contributing to health crises in the form of fossil fuel subsidies.

Sixty-nine of the 86 governments analysed were found to be subsidising fossil fuel production and consumption, for a net total of $400 billion in 2019.

At a time when fossil fuel companies are posting record profits and consumers are struggling with soaring energy bills, the Lancet report said that the plans of the 15 largest oil and gas companies were incompatible with safe levels of global warming.

It found that the firms were set to produce more than double their share of greenhouse gas emissions compatible with 1.5 degrees Celsius of warming by 2040. Capping warming at 1.5C is the more ambitious target of the Paris climate deal.

At the current rate it would take 150 years to fully decarbonise the energy system, a far cry from international 2050 net-zero target.

“Current strategies from many governments and companies will lock the world into a fatally warmer future, tying us to the use of fossil fuels that are rapidly closing off prospects for a liveable world,” said Paul Ekins, professor of Resources and Policy at University College London’s Bartlett School.

He said climate and health emergencies were the result of a “deep failure” by governments to recognise the urgent need to work towards a zero-carbon world.

The authors called for a “health-centred response” to the energy, cost of living and climate crises.

Improving air quality would help prevent deaths resulting from fossil fuel exposure, of which there were 1.3 million in 2020 alone.

Accelerating the move towards plant-based diets would reduce 55 per cent of agricultural emissions and prevent up to 11.5 million diet-related deaths annually, the authors said.

UN chief Antonio Guterres, responding to the report, said that the world’s fossil fuel “addiction” was “out of control”.

“The science is clear: massive, common sense in renewable energy and climate resilience will secure a healthier, safer life for people in every country.”