The deadly heat wave that has ravaged large parts of Mexico, Central America and the southern US in recent weeks has become 35 times more likely due to human-induced global warming, according to research from leading climate scientists at World Weather Attribution (WWA).
Tens of millions of people suffered dangerous day and night temperatures as a heat dome engulfed Mexico – a large and persistent high-pressure zone stretching north into Texas, Arizona and Nevada, and south across Belize, Honduras, Guatemala and El Salvador. .
A heat wave can be caused by several factors, including a heat dome, which traps warm air close to the ground, preventing cool air from entering and causing the temperature on the ground to rise and remain high for days or weeks. In May and early June, the heat dome hovered over the region, breaking multiple daily and national records and causing widespread misery and disruption, especially among the poorest and most marginalized communities.
Such extreme heat episodes are four times more likely today than at the turn of the millennium, when the planet was 0.5 degrees cooler, the WWA analysis found.
“It is not surprising that heat waves are becoming increasingly deadly. We have known about the dangers of climate change since the 1970s. But thanks to spineless politicians who time and again give in to lobbying for fossil fuels, the world continues to burn enormous amounts of oil, gas and coal,” said Friederike Otto, co-author of the study and senior lecturer in climate science at the University of California. Grantham Institute, at Imperial College London.
According to the study, without meaningful political action to phase out fossil fuels, deadly heat waves will be “very common in a 2C world.”
Extreme heat increases rates of heart, respiratory and kidney disease, and threatens to overwhelm electricity supplies, health care facilities and other infrastructure.
At least 125 people have died and thousands more have suffered heatstroke since March in Mexico, where temperatures reached nearly 52 degrees Celsius on June 13 – the hottest June day on record in the country. The extreme heat worsened Mexico’s severe drought and air pollution, causing power outages, water shortages, thousands of forest fires and a mass die-off of endangered monkeys and birds. The actual mortality and morbidity rate is still unknown.
In Phoenix, the hottest major city in the U.S., 72 suspected heat deaths were investigated by the Maricopa County Medical Examiner’s Office as of June 8 — an 18% increase from the same period last year. In the southwestern US, more than 34 million people were under a heat warning and dozens of people suffered from heat exhaustion at political rallies.
In Guatemala’s Dry Corridor, the hottest and driest part of the country where most people earn their living by backbreaking farm work, schools were closed as temperatures reached 45 degrees, leaving some of the region’s poorest communities faced with failed harvests and severe water shortages.
In Honduras, electricity has been rationed and smoke from uncontrolled forest fires has contributed to the worst air quality ever recorded in the capital Tegucigalpa.
The death toll across Central America, one of the world’s most vulnerable regions to the impacts of the climate crisis due to its geographic location, high levels of poverty and inequality, poor infrastructure and governance, and a lack of heat warning systems, is unknown.
Previous studies have shown that the frequency and intensity of heat waves, the deadliest form of extreme weather, has increased in recent years due to the climate crisis, which is caused by the burning of fossil fuels and other human activities such as deforestation and industrialized agriculture.
May this year was the warmest May on record worldwide – breaking a record for the warmest month for the thirteenth month in a row.
To quantify the effect of human-induced warming on recent extreme temperatures in North and Central America, a team of international scientists analyzed weather data and climate models using peer-reviewed methods to compare how these types of events have changed between the current climate, with about 1.2°C global warming, and the cooler pre-industrial climate.
The WWA researchers looked at the five-day maximum temperatures in North and Central America in May and June. The analysis found that the climate crisis made daytime extreme heat around 1.4 degrees Celsius hotter – and 35 times more likely than in pre-industrial times.
The effect on nighttime temperatures is even stronger: the analysis shows temperatures are about 1.6 degrees Celsius higher – a 200-fold increase due to global warming. Hot nights are particularly dangerous to human health because the impact of heat is cumulative and the body only begins to rest and recover when the temperature drops below 27 degrees Celsius.
If fossil fuels are not phased out, the frequency and intensity of heat waves will continue to increase, leading to more deaths, diseases, economic losses, hunger, water shortages and forced migration among the world’s hardest-hit communities – those that have contributed the least climate crisis.
“As long as humans fill the atmosphere with fossil fuel emissions, the heat will only get worse – vulnerable people will continue to die and the cost of living will continue to rise,” said Izidine Pinto, co-author and researcher at the Royal Netherlands Meteorological Institute. Institute.
Yet so much damage has already been done to the planet that deaths and disruptions caused by the heat will continue to rise unless local and national governments rethink every aspect of life, including urban planning, water conservation, shade, school sports and the protection of outdoor workers .
Karina Izquierdo, urban advisor for the Latin American and Caribbean region at the Red Cross Climate Center, and co-author of the study, said: “Every fraction of a degree of warming exposes more people to dangerous heat… In addition to reducing emissions, governments and cities must take steps to become more resilient to heat.”