Living With Climate Change: July 2023 is the hottest month ever recorded. Blame global warming and El Niño.

All three say the combined temperature data for July so far and projections for continued extreme heat in the final days of the month position this July as the hottest month ever — and by a wide margin.

Related: ‘The hottest I ever remember’: Phoenix scorches above 110 for a record 19th straight day

A release from Leipzig University and another from the WMO and the Copernicus Climate Change Service, known as C3S, said July temperatures were about 1.5 degrees Celsius (2.2 degrees Fahrenheit) above preindustrial levels. That rise is tied to human-caused global warming and includes a boost to temperatures from El Niño, the recurring weather phenomenon whose latest impact, scientists say, is only beginning.

Related: Here comes El Nino: It’s early, likely to be sloppy and add even more heat to a warming world

Read: Already roasting in extreme heat? 2024 could be even hotter, NASA scientists warn.

More than 100 million Americans have routinely been under heat warnings over the past few weeks. Globally, July is the hottest month on average in any given year, but even regular hot spots like Phoenix, Ariz., and parts of Texas have suffered under unrelenting strings of days when the mercury has been well above 100 degrees Fahrenheit, and “real-feel” factors including humidity make conditions even more brutal.

Phoenix, where residents have received third-degree burns from sidewalks and pavement, will be the first major city in the U.S. to average 100 degrees for an entire month. It has seen a record 26 days — and counting — with highs above 115 degrees. 

Notably, July’s global temperature gain matches the overall atmospheric warming limit that most countries have pledged to maintain under the voluntary Paris climate accord, a 2015 pact that takes aim at climate change caused by the burning of fossil fuels such as coal, oil
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July’s temperatures do not mean the world has passed that point permanently — overall, the planet has warmed by about 1.2 degrees Celsius, or 2.2 degrees Fahrenheit, since preindustrial times — but extremes like this month, which followed a sizzling June, tell scientists that Earth is likely to reach that alarming number without immediate and significant reductions in emissions of greenhouse gases such as carbon dioxide and methane.

Related: What if heat waves were named like hurricanes? New push draws mega insurers, Athens and Miami mayors, Red Cross and dozens more stakeholders

“The extreme weather which has affected many millions of people in July is unfortunately the harsh reality of climate change and a foretaste of the future,” said WMO Secretary-General Petteri Taalas in a press release. “The need to reduce greenhouse gas emissions is more urgent than ever before. Climate action is not a luxury but a must.”

July also follows the planet’s hottest June on record, making for dangerous conditions for many parts of the world this summer.

A silent killer

There is no doubt that extreme heat is already harming people around the world. So far in 2023, heat waves across three continents in the Northern Hemisphere have broken records, made many people sick and caused deaths from heat stroke, heat exhaustion, dehydration and related illnesses — and this extreme heat is likely to continue through August.

Heat waves, sometimes called silent killers, are already the leading cause of weather-related deaths in the U.S. and will intensify in frequency and severity as human-caused climate change increases global temperatures. Leading public-health journals and medical organizations have said climate change poses the biggest threat to public health in the coming years.

And because high healthcare costs already burden some U.S. families more than others, recent climate-change research has focused on heat and health.

A report from the public-policy research group Center for American Progress estimates that extreme heat will result in $1 billion in additional healthcare-related costs in the U.S. this summer alone.

That group projects that excessive heat will prompt roughly 235,000 emergency-department visits and more than 56,000 hospital admissions for conditions related to increased body temperature this summer.

Read: The cost of extreme heat in the U.S.? 235,000 ER visits and $1 billion in healthcare bills this summer alone.

Last year in Europe — during the continent’s hottest summer on record — an estimated 61,600 people died from heat-related causes, another indication that heat-preparedness strategies are falling short. Last year’s extremes in parts of Europe are being followed by another round of high temperatures this year.

It’s the specifics of this run of extreme temperatures that have observers on alert. High nighttime temperatures — a hallmark of human-caused climate change, according to some scientists — makes the heat even more dangerous, because it deprives our bodies of the chance to cool down if air conditioning is not available.

A global-warming wake-up call

Whether it’s because they’re experiencing the brutality of so many extremely hot days or paying greater attention to how it affects people who work outside or who can’t afford air conditioning, Americans have stepped up their level of concern about the heat.

A survey in the spring of 2023 by Yale University’s Program on Climate Change Communication found that 72% of Americans are at least “a little” worried about the effects of extreme heat in their local area. And extreme heat tops the list of worries about climate impacts such as drought, flooding and water shortages.

Additionally, 75% of Americans think that global warming is affecting extreme heat at least “a little,” including 42% who say global warming is affecting it “a lot.” 

According to the Yale researchers, “it’s important for communicators to emphasize the connection between climate change and extreme weather events (e.g., heat waves, wildfires) and how these events directly impact people’s health, the economy and public infrastructure. Experience with climate impacts can be a powerful teacher.”

Research indicates that hot, dry days have been more likely than other extreme weather events to cause people to say they have experienced global warming.

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