While scorching heat may not seem as dramatic as other natural disasters (read: floods and tornadoes), the U.S. National Weather Service has deemed it the deadliest weather hazard over the past 30 years. It's especially dangerous during summer when the northern half of the planet is tilted toward the sun, and the northern hemisphere receives increased daylight hours and warmth.

When it comes to heat waves, there seems to be no universal definition of the term as it is relative to local weather conditions. But the same National Weather Service refers to it as a period of abnormally hot weather generally lasting more than two days with high temperatures of at least 90 degrees.

Heat waves begin when high pressure in the atmosphere (also known as an anticyclone) builds up, moves in, and pushes warm air toward the ground. That creates a sinking column of air that warms up further as it is compressed. While moisture in the earth can blunt the effects of the heat (the same way our bodies evaporate sweat to cool the body), with so little water in the soil, there isn’t as much to soak up the heat. So as the ground warms, it often dries out, trapping the latent heat already absorbed by the landscape to heat up even more.

Then, the high-pressure system acts as a cap or a lid on a pot, otherwise known as a "heat dome". It even pushes out cooler, fast-moving air currents and minimizes wind and cloud cover, which gives the sun an open line of sight to the ground. It’s also why heat waves place themselves over an area for several days or longer.

To learn more about these sweltering heat waves and the effects they have on our health and the state of the world in general, we reached out to Jessica Kleczka, a climate psychologist, environmental social scientist, and climate justice activist. "The current heat wave in Europe has led to droughts, crop failures and thousands of heat deaths," she told Bored Panda.

"The UK was forced to declare a red weather warning for heat for the first time in history, with temperatures breaching 40°C [104 °F] in London. While there is not enough data on this particular heat wave yet, we know that the last major heat wave in 2018 was made 30 times more likely by climate change, and we can expect similar conclusions to this current extreme weather event," Kleczka added.

While it may seem tricky to pinpoint how a specific weather event was influenced by climate change, Kleczka explained, "Climate breakdown is primarily driven by the burning of fossil fuels, which contribute around 90% of global CO2 emissions."

"The International Energy Agency said last year that there can be no new coal, oil and gas if we are to avert dangerous heating," she continued. "What we need to see now are ambitious policies from global political leaders in the run-up to COP27 [The 2022 United Nations Climate Change Conference], away from these dirty fuels and towards renewables and energy efficiency."

The dire reality is that climate change caused by greenhouse gasses from burning fossil fuels is poised to make heat waves longer, stronger, and more common. But Kleczka pointed out that a growing number of studies now show that additional warming can be halted within a few years — but only if we act with urgency.

"Ambitious climate action can be very effective and avert the worst impacts of climate breakdown, if done the right way. Any approach must center the most vulnerable people, those on the frontlines of the climate crisis, and Indigenous communities who protect 80% of global biodiversity," she said.

When it comes to the major cities, however, the summers there shape up to get warmer, according to the U.S. Environmental Protection Agency (EPA). See, hot spells are occurring more often than they used to in the big cities across the country. Their frequency has increased gradually, "From an average of two heat waves per year during the 1960s to six per year during the 2010s and 2020s".

Small wonder, as urban areas further exacerbate the heat, and you can clearly see the examples in this list. Cities like Houston or New Orleans experience higher temperatures than outlying areas because their roads, parking lots, and buildings cover natural areas and absorb more heat than their surroundings. A phenomenon that's also known as the urban heat island effect.

As the EPA stated, "Structures such as buildings, roads, and other infrastructure absorb and re-emit the sun’s heat more than natural landscapes such as forests and water bodies." In these areas, daytime temperatures are about 1–7°F higher than in outlying areas, and nighttime temperatures are about 2-5°F higher.

These numbers affect our health, our lifestyles, and the economy in general. If humanity keeps going down this path, heat waves can turn densely populated parts of the world into uninhabitable territories in the future.

"We're already seeing major losses of fertile land around the world and large areas could become uninhabitable in the coming decades if urgent climate action is not taken — including coastal towns and cities in the global north," Kleczka explained. "These impacts are already happening close to home."

For certain parts of society, the impact will be even more challenging. "Marginalized communities, such as people of color and those living in poverty, tend to be disproportionately affected by heat waves due to poor quality of housing."

Kleczka continued: "In buildings that lack insulation, temperatures can be even higher than outdoors, leading to heat stress and premature death. This poses considerable risk to the elderly, chronically ill and disabled, who are more vulnerable to extreme temperatures as they can exacerbate pre-existing conditions."

Heat waves not only impact our physical health and well-being, but they worsen our mental health, too. "[They] have been linked to a rise in depressive episodes, anxiety, and suicide attempts. Researchers say that for every 1°C increase in monthly temperatures, mental health-related deaths increase by 2.2%."

Moreover, some medications prescribed to people who suffer these conditions "also increase the risk of heat-related death, while others become less effective in rising temperatures."

When these alarming weather phenomena seem on a path to increasingly impact our daily lives, it’s easy to feel like we’re running out of time to act. Thankfully, Kleczka offered some reassuring words on how everyone can strive to mitigate heat waves.

"It's important to remember that all is not lost if we keep pushing for political action," she said. "What we need to see now is a rapid shift away from fossil fuels, major investments in renewables, energy efficiency and home insulation, as well as climate finance and loss and damage to communities on the frontline, who have been made vulnerable by centuries of colonialism and continued exploitation."

"If we don't do these things, heat waves will grow in frequency and severity, but there is definitely still hope." If you want to take action, Kleczka mentioned a note-worthy campaign called the Fossil Fuel Non-Proliferation Treaty. Ever since 2019, this global initiative has aimed to phase-out fossil fuels and build a globally just transition for every worker, community, and country.

"The climate movement is strong and growing. The best thing people can do to tackle the climate crisis is to get involved in their local climate group (or remotely) and help build a political mandate for a just transition and sustainable future for all," Kleczka concluded.