The Conservation: Record heat has hit several countries across the Americas, Europe and Asia in 2024. In Mexico and Central America, weeks of persistent heat, with temperatures as high as 125 degrees Fahrenheit (51.8 Celsius), combined with prolonged drought have led to severe water shortages and dozens of deaths.

Extreme heat turned into tragedy in Saudi Arabia as over 1,000 people on the Hajj, a Muslim pilgrimage to Mecca, collapsed and died. Temperatures reached 125 F (51.8 C) at the Grand Mosque in Mecca on June 17.

In Greece, where temperatures were over 100 F (38 C) for several straight days in June, at least several tourists died or were feared dead after going hiking in dangerous heat and humidity.

India also faced temperatures around 120 F (49 C) for days in April and May that affected millions of people, many of them without air conditioning.

The heat wave that left more than 100 million people sweating across the eastern U.S. in June 2024 hit so fast and was so extreme that forecasters warned a flash drought could follow across wide parts of the region.

Prolonged high temperatures can quickly dry soils, triggering a rapid onset drought that can affect agriculture, water resources and energy supplies. Many regions under the June heat dome quickly developed abnormally dry conditions.

We study weather patterns involving heat. The June 2024 heat wave was unusually early and long-lasting compared with typical patterns for the Northeast U.S.

It was caused by a large high-pressure system called a heat dome that extended from the ground more than 10 miles up through the atmosphere. A heat dome is both a cause and an effect of extreme heat. Very large and strong heat domes, like the Northeast event – which reached higher into the atmosphere than any previous June event – have a greater potential for higher temperatures impacting more people.

It was also part of a global outbreak of early season heat that put lives at risk in many countries around the world.

Pakistan

BBC: The Edhi ambulance service says it usually takes around 30 to 40 people to the Karachi city morgue daily. But over the last six days, it has collected some 568 bodies – 141 of them on Tuesday alone.

It is too early to say exactly what the cause of death was in every case. However, the rising numbers of dead came as temperatures in Karachi soared above 40C (104F), with the high humidity making it feel as hot as 49C, reports said.

Civil Hospital Karachi admitted 267 people with heatstroke between Sunday and Wednesday, said Dr Imran Sarwar Sheikh, head of the emergency department. Twelve of them died.

“Most of the people who we saw coming into the hospital were in their 60s or 70s, although there were some around 45 and even a couple in their 20s,” Dr Sheikh told the BBC. Symptoms including vomiting, diarrhoea and a high fever.

“Many of those we saw had been working outside. We’ve told them to make sure they drink plenty of water and wear light clothes in these high temperatures.”

India

Water tanker drivers a lifeline as Delhi gripped by extreme heat

Context: NEW DELHI – As a scorching heatwave grips northern India, tens of thousands of people in Delhi have to cut back on showers, laundry and washing dishes because of a shortage of water.

With little to no piped water in many areas of Delhi, dozens of especially low-income neighbourhoods rely on tankers due to an acute water shortage the government blames on low levels in the Yamuna River – the capital city’s primary source of water.

People line up with jerry cans, buckets and barrels with temperatures hovering around 40 degrees Celsius (104°F). At the first sight of a tanker, they rush to climb on top and throw in their hoses in a race to fill their containers. Fights frequently break out.

Rise in night temperatures amid relentless heatwave leaves Indians sleepless

The climate connection

This isn’t normal

The Conservation: Although heat waves are a natural part of the climate, the severity and extent of the heat waves so far this year are not “just summer.”

A scientific assessment of the U.S. heat wave estimates that heat this severe and long-lasting was two to four times more likely to occur today because of human-caused climate change than it would have been without it. This conclusion is consistent with the rapid increase over the past several decades in the number of U.S. heat waves and their occurrence outside the peak of summer.

These record heat waves are happening in a climate that’s globally about 2.2 F (1.2 C) warmer than it was before the industrial revolution, when humans began releasing large amounts of greenhouse gas emissions that warm the climate.

Global surface temperatures have risen faster per decade in the past 30 years than over the past 120. NOAA NCEI

While a temperature difference of a degree or two when you walk into a different room might not even be noticeable, even fractions of a degree make a large difference in the global climate.

At the peak of the last ice age, some 20,000 years ago, when the Northeast U.S. was under thousands of feet of ice, the globally averaged temperature was only 10.8 F (6 C) cooler than now. So, it is not surprising that 2.2 F (1.2 C) of warming so far is already rapidly changing the climate.

Countries promised in 2015 as part of the Paris Agreement to keep warming well under 2 C, but current government policies around the world won’t meet those goals. Temperatures are on pace to continue rising, with the increase likely to more than double again by the end of the century.

If you thought this was hot

While this summer is likely be one of the hottest on record, it is important to realize that it may also be one of the coldest summers of the future.

For populations that are especially vulnerable to heat, including young children, older adults and outdoor workers, the risks are even higher. People in lower-income neighborhoods where air conditioning may be unaffordable and renters who often don’t have the same protections for cooling as heating will face increasingly dangerous conditions.

Extreme heat can also affect economies. It can buckle railroad tracks and cause wires to sag, leading to transit delays and disruptions. It can also overload electric systems with high demand and lead to blackouts just when people have the greatest need for cooling.

The good news: There are solutions

Yes, the future in a warming world is daunting. However, countries have made significant progress. In the U.S., the 2022 Inflation Reduction Act has the potential to reduce U.S. greenhouse gas emissions by nearly half by 2035.

Switching air conditioners to heat pumps and network geothermal systems can not only reduce fossil fuel emissions but also provide cooling at a lower cost. The cost of renewable energy continues to plummet, and many countries are increasing policy support and incentives.

There is much that humanity can do to limit future warming if countries, companies and people everywhere act with urgency. Rapidly reducing fossil fuel emissions can help avoid a warmer future with even worse heat waves and droughts, while also providing other benefits, including improving public health, creating jobs and reducing risks to ecosystems.

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