Temperatures of 25 ° C (77 ° F) are expected early in some places next week.
It is a heat that is most easily associated with half a bright summer day.
But while record-setting daytime temperatures are usually the headlines, when it comes to health, nighttime temperatures can be just as important.
People have little chance of recovering if temperatures remain high overnight, putting prolonged stress on the body. Next week’s suffocating nights could lead to an increase in heat-related health issues and it all comes at a time when the NHS is under unprecedented summer stress.
High night temperatures forecast for next week would mean more “tropical nights” are recorded in the UK, defined as when the temperature stays above 20ºC (68F).
The summer of 1975 was the first time the UK experienced four tropical nights in a single year, shows our analysis of Met Office data.
That August was also the first time the country’s more than 550 square miles experienced multiple suffocating nights.
Two decades later, the UK had one of the warmest summers on record. Northwest areas such as Manchester, Cheshire East, Copeland and Barrow-in-Furness were especially affected.
An additional 619 people died during July and August of the year in England and Wales. In addition, the mortality rate rose 16.1% in Greater London during the heat wave.
The 2004 heat wave is largely forgotten, as it happened a year in which more than 20,000 people died across Europe due to extreme heat.
On August 9 of that year temperatures remained above 20ºC overnight in 63 areas of the UK. Almost all of the East Midlands, East Yorkshire and Norfolk were affected by the heat wave.
In the last 10 years, high temperatures have been recorded in 27 nights. That’s three times more than in the 1960s.
Is this a trend? The Met Office says tropical nights are too infrequent in the UK to say for sure.
Why do hot temperatures cause death?
The heat does not affect us all equally.
As with COVID-19, some groups are more vulnerable than others.
Dr Sandy Robertson, emergency physician and chairman of the environmental group at the Royal College of Emergency Medicine, told Sky News that cardiovascular problems become more frequent during heat waves.
“Your body is able to catch a cold from sweat and that means your body dehydrates, which makes your blood thicker. This causes all kinds of heart problems and increases the risk of stroke. “Dr. Robertson said.
Respiratory problems are also aggravated by heat, which can get worse as air pollution often increases with warmer weather.
The result is that those with underlying health conditions, who also tend to be older, are at greater risk during periods of heat.
The excess of deaths attributed to three heat waves in 2020, which killed more than 2,500, show that those over 65 were disproportionately affected.
But age is not the only factor that determines who is vulnerable.
Some studies suggest that older women have a higher risk. In 2003 a heat wave in northern France killed 15,000 people, 65% of whom were women.
It has also been found that people with mental health problems have a slightly higher risk of heat-related problems.
Dr. Robertson said there is some evidence that suicidal ideation increases with heat: “Research looking at Mexico and the United States has shown that by 2050, if we follow the current course of climate change, there will be between 9,000 and an additional 40,000 suicides in these countries. “
It is also believed that those who live alone and in poorly ventilated homes are at higher risk, as are those who live in large cities.
The following map shows the areas of England and Wales where heat-related mortality rates have been highest since 2000. Darker spots around London, Birmingham and Manchester show that the people from these cities have been one of the hardest hit.
The exact explanation of some of the geographical patterns is not yet clear.
The quality of housing, people’s access to information about what they should do during heat waves, and other socioeconomic factors probably play an important role.
“We know many of the correlates associated with the increase in deaths due to heat, but we don’t always know the exact causal mechanisms through which these things take effect,” said Professor Antonio Gasparrini, a biostatistician at the London School of Hygiene and Medicina Tropical.
Another influence that explains city-countryside disparities is likely to be the effects of urban heat island. It is when roads and city buildings absorb and then emit heat, making urban areas warmer.
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1:41 What is the urban heat island effect?
Dr. Eunice Lo, a climate scientist at the University of Bristol, says this is likely to get worse, especially at night, as the weather continues to warm the planet.
“We are projecting an intensified urban heat island effect at night. Warm nighttime temperatures are important because they should be when we recover from the daytime heating load,” he said.
The possibility of more frequent heat waves and warm nights is especially worrying given the relationship between people dying and very high temperatures.
The following graph shows how the risk ratio (the probability of dying from any cause) increases dramatically with small temperature changes at the warmer end of the temperature graph.
“The rate of increase in mortality risk is much higher at extremely warm temperatures, compared to relatively warm temperatures,” Dr. Lo said.
However, it is not inevitable that higher temperatures will cause thousands of deaths. Studies have shown that in warmer countries than the UK, fewer heat-related deaths tend to occur at the same temperatures.
He suggests that adaptation, both in the form of people’s behavior and in building infrastructure more able to cope with warm weather, can help save lives.
Methodology
The 5 km Met Office HadUK-Grid minimum temperature data set was used for the analysis. According to the Met Office, grid data smooths out peaks captured by individual weather stations. This means that the analysis of Sky News temperature data is likely to underestimate areas where temperatures could have risen beyond 20ºC.
The Data and Forensics team is a multi-purpose unit dedicated to providing transparent Sky News journalism. We collect, analyze, and visualize data to tell data-based stories. We combine traditional reporting skills with advanced analysis of satellite imagery, social media, and other open source information. Through multimedia narration we aim to better explain the world while showing how our journalism is done.
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