Opinion: Global warming will bring more heat waves — and greater health risks

The sun rises in Encinitas
The sun rises over Encinitas on a warm morning. REUTERS/Mike Blake/File Photo

Recently, “Zoe” became the first named heat waveand in just one week, sixty heat records were broken across the country. We are in a “global odditya term popularized by Thomas Friedman in 2010, except now “weird” has become the new norm.

While daily headlines may make extreme heat patterns seem like a new phenomenon, scientists have been predicting the effects of global warming since the beginning 19th century. Despite the alarm bells, greenhouse gases such as carbon dioxide and methane (which have an impact on global warming which is 84 times higher than CO2) led to high levels of heat trapping – approximately double today compared to 15 years ago.

This amount of heat trapping leads the world on a steady path beyond the current Increase of 1.1 degrees Celsius in global temperature. Soon we might reach a 1.5 degree warmingand with it, scorching heat waves that will occur four times more often than the typical decade-long phenomenon.

As a physician, the health effects of this weirdness, especially with extreme heat, are deeply concerning.

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

As the temperature rises, it becomes more difficult for the body to sweat and avoid overheating. Body temperature can reach 106 degrees or more in 10 minutes – a temperature that is essentially incompatible with life.

Overheating comes with a number of health hazards: increased risk of skin cancer, dehydration, heat stroke, kidney disease, and heart disease. Many of the patients I care for who suffer from respiratory conditions such as asthma find that the hot weather makes it even harder to breathe.

Additionally, high temperatures are often found as part of still air, allowing air pollutants like ground-level ozone to stagnate. Ozone can reduce lung function. For each degree Celsius increase in temperature, ozone can kill 22,000 additional people.

Unfortunately, oppressive heat affects the health of some populations more than others. Children are particularly vulnerable to heat stress, as they are unable to regulate body temperature the same as adults. Pregnant women, whose body temperature is already higher to begin with, are more at risk of heat exhaustion and heat stroke when their body reaches 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-related causes than those housed. For people with chronic mental disorders, studies have shown that rising temperatures may be linked to higher suicide rates.

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

A study found that the emergency room visit rate for heat-related causes increased by 67% for blacks compared to 23% for whites. Another found that cardiovascular mortality extreme heat was higher in black adults than in white adults.

The recent triple digit heatwave led my own patients to look for for cooler temperatures wherever they could. Many feared that their access to air conditioning would be at risk at such high temperatures.

In order to prevent the health problems that can come from oppressive heat, state and local interventions could help protect those most vulnerable. The recently signed Extreme Heat Action Plan create the first national extreme heat warning and rating system, which will allow communities to better prepare for heat waves. Cities and counties will receive funding to build climate-resilient neighborhoods, which could include creating tree canopy in neighborhoods or using heat-resistant building materials.

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

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

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

Teresa H. Sadler