Sun rises in Encinitas
The sun rises over Encinitas on a hot morning. REUTERS/Mike Blake/file photo

Recently, “Zoe” became the world’s first named heatwave, and in just one week, sixty heat records were broken across the nation. We are in a “global weirding,” a term popularized by Thomas Friedman back in 2010, except now “weird” has become the new normal. 

While daily headlines may make it seem like extreme heat patterns are a new phenomenon, scientists have been predicting the effects of global warming since the early 19th century. Despite the warning bells, greenhouse gasses like carbon dioxide and methane (which has a global warming impact that is 84 times higher than CO2) have led to high levels of heat trapping — roughly double today compared to 15 years ago.

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This amount of heat trapping is leading the world on a steady track beyond the current 1.1 degree Celsius rise in global temperature. Soon we could reach a 1.5 degree warming, and with it, blistering heat waves that will happen four times as often rather than the typical once-in-decade phenomenon.

As a physician, the effects of this weirding on health, particularly with extreme heat, is deeply concerning.  

Human bodies are designed to withstand heat through sweating, but the extremes of climate change are driving us to a point where sweating may not be enough. Climate scientists track this ability using “wet-bulb temperature.” Wet-bulb temperature reflects the amount of heat and water that are present in the air. 

As the temperature increases, it becomes more difficult for the body to sweat and prevent overheating. The body’s temperature can reach 106 degrees or higher within 10 minutes — a temperature that is essentially incompatible with living. 

With overheating comes a number of health dangers: increased risks of skin cancer, dehydration, heatstroke, kidney disease, and heart disease. Many of the patients I care for, who suffer from respiratory conditions like asthma, find that hot weather makes breathing even more difficult.

Additionally, high temperatures are often found in the setting of still air, allowing air pollutants like ground-level ozone to stagnate. Ozone can reduce lung function. For every one degree Celsius rise in temperature, ozone can kill an additional 22,000 people. 

Unfortunately, extreme heat impacts the health of certain populations more than others.  Children are particularly vulnerable to heat stress, as they are unable to regulate their body temperature in the same way as adults. Pregnant people, whose body temperatures are already higher at baseline, are at greater risk for heat exhaustion and heat stroke when their bodies reach 102 degrees.

Outdoor workers in industries like construction and agriculture face grueling hours in extreme temperatures, exposing them to more work-related injuries. Homeless populations face a 200 times higher risk of dying from heat-associated causes than sheltered people. For those with chronic mental health conditions, studies have shown that rising temperatures could be linked to higher suicide rates.  

Black Americans also unjustly face the burden of extreme heat, despite their households producing far less CO2 than their white counterparts. Historically racist practices such as redlining have forced Black communities to live in urban heat islands. With little tree cover, large amounts of sun-absorbing concrete, and less access to air-conditioning, Black Americans are more likely to suffer the dire consequences of extreme heat.

One study found that the rate of emergency department visits for heat-related causes increased by 67% for Black people in comparison to 23% for white people. Another found that cardiovascular mortality from extreme heat was higher in Black adults when compared to white adults.  

The recent triple-digit heatwave led my own patients to search for cooler temperatures wherever they could. Many worried that their access to air-conditioning was at risk in such high temperatures.  

In order to prevent the health problems that can come from extreme heat, state and local interventions could help to protect those who are the most vulnerable. The recently signed Extreme Heat Action Plan will create the nation’s first extreme heat advance warning and ranking system, which will allow communities to better prepare for heat waves. Cities and counties will receive funding to build climate resilience districts, which could include creating more tree cover in neighborhoods or requiring the use of heat-resistant building materials.  

There are also energy collectives like San Diego Community Power that help communities take back control of energy from private corporations. Additionally, to reduce fossil fuel emissions beyond electric vehicle use, cities could follow the San Diego Association of Governments’ mission to encourage active transportation methods like walking and biking.

At one point, more than 100 million Americans have been under an excessive heat advisory.  Without serious, decisive climate action, the number of people and the frequency of these advisories will only increase. And we will jump past the point of adaptability, losing our chance to survive. 

Christine James, M.D., M.Sc., is an allergist-immunologist with UC San Diego Health and a member of the Public Health Advisory Council of Climate Action Campaign. She is a Public Voices Fellow with The OpEd Project and the Yale Program on Climate Change Communication. Follow her on Twitter @ChristineRJames.