More than 450,000 excess deaths could occur as a result of hotter weather caused by the “Godzilla” El Niño over the next six months, according to climate scientists.

Huge numbers of further deaths are also forecast due to the droughts, wildfires and flooding that the phenomenon is expected to bring.

The projection of 450,000 deaths, published in a report by the Climate Impact Lab at the University of Chicago, is based on the observed relationship between temperature and excess deaths.

El Niño is a natural climate cycle which leads to rising ocean temperatures, with recent data showing the Pacific is around 2.6C above the 30-year average.

It is forecast to peak at around 4C above average by November, according to the average of 14 different models, which has led climate scientists to predict 2027 becoming the hottest year ever recorded.

The heat deaths have been estimated at regional level, with researchers saying the projections have identified where measures to protect people could be put in place and save lives.

These actions could include better heat forecasts, cooling centres where people can shelter, increased staffing for medical facilities, and protections for outdoor workers.

Professor Michael Greenstone, co-founder of the Climate Impact Lab who co-authored the report, said: “The estimate of 451,000 people is such a large number that it can be numbing, but it is made up of parents and children, grandparents and neighbours, people going to work, caring for families, and living their lives.”

The estimate of deaths covers September 2026 to February 2027, when current temperature forecasts end - but higher levels of heat deaths are expected to continue into the middle of next year.

While El Niño will strike across the globe, most of the deaths estimated will be in the southern hemisphere, due to the extra heat during the spring and summer there.

Another wave of deaths in the northern hemisphere’s spring could then come should El Niño persist as expected.

The most affected countries in the next six months are Nigeria, Indonesia, Sudan, India and Brazil.

African and south-east Asian will be most heavily affected, according to the report.

The US is also in the top 20 most impacted nations, with 3,500 projected additional heat deaths.

Italy is the only European nation appearing in the top 50 most affected countries, with 780 additional heat deaths being projected.

Report co-author Dr Tamma Carleton at the University of California, Berkeley said: “Increasing emergency response and better targeting our efforts can save many lives this year.

“But 20 years from now, once today’s extreme temperatures become the new normal, we don’t want to be in a constant state of emergency. We need to mobilise now to design, deploy and evaluate the tools that will save lives in the years ahead.”

Food supplies will also be hit by the event, with the World Food Programme warning that its impacts could push 50 million people into acute hunger and drive prices up.

Prof Greenstone added: “People have been able to forecast when there’s going to be shocks to crops, and give advance warning of that.

“This new report is opening the door to being able to do it for an even more important outcome - I would say the most important outcome - which is death.”