It’s getting hot out there

Not surprisingly, 2024 recorded the highest temperatures in recent human history. I am talking to a 12-year-old about it, and I realize this paradox:

By the time they reach my age, they will fondly look back to 2024 as having the lowest temperatures in their memory!

The faster our world heats up, the faster the divide between the cooled and the cooked will widen. It is symptomatic of the larger injustice of the rising temperatures on our planet that the people who have done the least to cause it are the ones who will suffer the most from its impacts. The rising temperatures are not only changing our world; it is also dividing it further.

In the United States, those suffering the consequences of high temperature are often people of color and immigrants. Latinos account for one-third of all worker heat fatalities, while farmworkers (such as those working with a H2A visa) face the highest rates of death from heat-related injuries and illnesses. All in all, low-paid workers suffer five times as many heat-related injuries as their highest-paid counterparts.

Jeff Goodell’s 2023 book, The Heat Will Kill You First: Life and Death on a Scorched Planet puts the division between the cooled and the cooked in stark perspective. The book details catastrophic consequences of heatwaves, such as the 2003 European heatwave that killed an estimated 72,000 people, including 15,000 in Paris, and the 2021 Western North American heatwave that resulted in 1,400 deaths, including 600 in British Columbia, Canada. Goodell also reports on the deaths of individuals like Jonathan Gerrish, Ellen Chung, and their infant child, who died during a hike in California as temperatures reached 109°F (43°C), and Sebastian Perez, an undocumented worker who died while working in 107°F (42°C) heat in British Columbia.

For outdoor work most agree that temperature above 32°C (90°F) are particularly hazardous.

Biology

The risk of heat-related illness increases significantly especially when both the temperature and humidity rises. High humidity hampers the ability of the body to evaporate fluids from the skin, which is how it cools itself. When the so-called wet bulb temperatures exceed 35°C (95°F) it makes it impossible for the body to cool down without external intervention like air conditioning.

There’s increasing evidence that prolonged exposure to high temperatures can permanently damage your kidneys. It may speed up your biological clock and age you as much as smoking or drinking.

As core body temperature rises, proteins begin to denature above approximately 42°C (107°F), disrupting cellular function and leading to heat stroke, a life-threatening condition that can cause permanent brain damage in up to 20% of survivors.

Cellular stress from heat exposure impairs protective systems like heat shock proteins and autophagy, especially in older adults, leading to the accumulation of damaged proteins and increased inflammation, which heightens vulnerability to severe health impacts.

Long-term exposure to heatwaves has been linked to lasting epigenetic changes in DNA, such as altered methylation patterns, which can persist after recovery and affect gene expression related to immune function and heat resilience, potentially impacting future generations.

Heat stress also contributes to dehydration, electrolyte imbalance, and increased blood viscosity, all of which strain the heart and kidneys, and are associated with higher risks of heart attack, stroke, and acute kidney injury.

Heat exhaustion, can lead to dizziness, nausea, fainting, and ultimately heatstroke.

The body can recover from the effects of high temperature given a long enough period of lower temperatures. Higher nighttime temperature limit the time the body has to recover from daytime heat.

In summary: Extreme high temperatures pose a serious challenge to having and maintaining a healthy body.

How hot is too hot?

Guidance derived from medical research suggests that a reasonable comfortable work temperature indoors is generally considered to be between 16°C and 24°C (61°F and 76°F). For outdoor work most agree that temperature above 32°C (90°F) are particularly hazardous.

In the UK, the Trades Union Congress (TUC) recommends a legal maximum indoor temperature of 30°C (86°F), or 27°C (80°F) for physically demanding work.

In the US, there is no universal legal temperature limit. It is generally considered too hot to work outdoors safely when the heat index reaches 90°F (32°C), with the risk escalating significantly above 100°F (38°C)

In the US, OSHA (Occupational Safety and Health Administration) provides guidance and recommendations. The agency’s Heat Safety Tool app advises increased precautions when temperatures exceed 80°F (27°C), and identifies temperatures above 90°F (32°C) as particularly hazardous. The app recommends that employers implement protective measures when the heat index exceeds 90°F (32°C).

The US CDC (Centers for Disease Control and Prevention) further recommends reducing work schedules when the heat index reaches between 100°F (38°C) and 107°F (42°C), and suggests that outdoor work should be cancelled or rescheduled above 108°F due to the grave health risks.

Should government set boundaries?

While not bound by heat index numbers, in the US employers are legally required under the General Duty Clause to provide a workplace free from recognized hazards, which should include excessive heat.

Whether legal limits should be put on working in high temperatures to prevent fatalities and injuries seems separate from climate change opinions. Like at the time of the introduction of seatbelt laws, there are those that feel government should stay out of the business of telling employers how to handle this reality, while others argue that setting legal boundaries to protect workers is justified.

In the summer 2024, the US department of Labor published a proposed federal rule. It suggests requiring employers to develop heat injury and illness prevention plans, implement cooling measures and train workers on heat risks. Since the publication of these proposed rules, a new government has come into power. Given the tendencies of that new administration, it doesn’t seem likely that this rule will get the force of law as initially intended.

A handful of US states, including California and Colorado, have passed laws to protect workers from extreme heat. Others, notably Florida and Texas, have gone the opposite way. The Texas law, for example, prohibits cities and counties from requiring water breaks for outdoor workers. Instead, as one boss explained it to me: being ‘Texas tough’ is the solution.

More air conditioning means escalating the warming climate trend

It is somewhat ironic that our primary defense against living and working in hotter temperatures is air conditioning technology, which in itself contributes to global warming. As the planet warms, air conditioning becomes a necessity, allowing people to live in or migrate to extremely warm climates. Thus, the use of air conditioning grows exponentially and so does its contribution to global warming with increasing electricity use and greenhouse gas emissions. It’s a mean, vicious, circle.

Reducing emission of CO2 and other gasses.

Ultimately, the only way out is taming the hot temperatures. And that, it seems inevitably so, requires reducing the emission of the gasses that fuel the warming of the planet. And that in turn means there is not much room for fossil fuels in our future.

It’s as simple and as complicated as that.