A recent study published in the journal Nature Medicine shows that more than 60,000 people died of heat-related causes in Europe last summer.
According to the study, only a small share of heat-related deaths come from heatstroke. In most cases, hot weather kills people by stopping the body from coping with existing health problems like heart and lung disease.
2022 was the fifth warmest year on record globally.
However, this year is already forecast to be hotter than 2022. What's worse, a new analysis done by Berkeley Earth concludes that there's now an 81 percent chance this year will be the warmest on record.
People walk with parasols in the scorching sun in central Tokyo's Ginza district, Japan, July 16, 2023. /CFP
With an ongoing heat wave engulfing the Northern Hemisphere, countries like the U.S., Spain, Italy and Greece have seen extremely high temperatures in recent weeks.
On July 18, the UN World Meteorological Organization (WMO) warned that heat waves are among the deadliest natural hazards, and the dangers associated with the heat wave aren't over yet.
"Repeated high night-time temperatures are particularly dangerous for human health because the body is unable to recover from sustained heat," said John Nairn, WMO senior heat advisor. "This leads to increased cases of heart attacks and death."
During hot weather, the body has to work harder to keep its core temperature at normal levels, which puts extra strain on the heart, lungs and kidneys.
A traffic warden manages his street corner under the hot sun in Las Vegas, U.S., on July 12, 2023. /CFP
Extremely high temperatures not only increase the risk of heart disease, but they also increase the risk of dengue.
More than three million cases of dengue have been reported in the Americas so far this year, which means 2023 already has the second-highest annual incidence of the disease since 1980, according to the journal Nature.
Dengue's main vector, the Aedes aegypti mosquito, thrives at temperatures around 30 degrees Celsius and in humid conditions, which have become more frequent in the past few years as a result of record heat and extreme weather events.
A worker fumigates against the dengue virus in Dhaka, Bangladesh, on Sunday, July 9, 2023. /CFP
The increasing temperatures contribute to longer dengue seasons and could drive the geographical expansion of the disease.
In Brazil, where nearly 2.4 million cases have been reported this year, the disease is expanding into southern states that were previously too cold for mosquitoes. Over the past five years, 481 Brazilian municipalities have registered sustained local transmission of dengue for the first time, according to an analysis by Cláudia Codeço, an epidemiologist at the Oswaldo Cruz Foundation, a biosciences and public-health institution in Brazil.
Also, as global temperatures increase, the seasons of the typically seasonal dengue (case numbers tend to go up in the summer or the rainy season and down in the winter or the dry season) might get longer.
"We found that the transmission seasons generally increased by about a month on either end," said Andrew Brouwer, a computational epidemiologist at the University of Michigan.
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