Heat waves have become a significant concern across the United States, posing health, infrastructure, and environmental risks. Characterized by prolonged excessively high temperatures, heat waves are becoming increasingly frequent and intense. As per the United States Environmental Protection Agency, the frequency and intensity of heat waves have shot up, from an average of two heat waves during the 1960s to six per year from 2010 to 2020.
A heat wave is typically defined as scorching weather that lasts two or more days. The temperatures during a heat wave exceed the average maximum temperature for a given region by a significant margin.
Let’s find out 9 things about heat waves in the USA.
Historical Perspective
Heat waves are not a new phenomenon in the USA. The heat waves in July 1936, a part of the period known as the ‘Dust Bowl,’ are considered the most severe in US history, with temperatures above 100°F (38°C) across multiple states. The summer of 2023 is reported as the hottest year on record in the last 2000 years. However, the temperatures of July 2024 are set to break all records as an intense heat wave engulfs the West. Palm Springs hit a never-before-see 124 degrees on 5th July 2024.
Geographic Variations
Heat waves affect various regions of the USA differently. For example, the Southwestern states, including Arizona and Nevada, frequently experience extremely high temperatures due to their arid climates. In contrast, the Northeastern states, such as New York and Massachusetts, have seen increased heat wave occurrences and intensity despite traditionally milder summers.
Climate Change
Rising global temperatures contribute to more intense and prolonged heat waves. According to the Climate Science Special Report, the average temperature in the contiguous United States has increased by 1.2°F (0.7°C) over the past century. It is projected to rise to 2.5°F (1.4°C) for 2021-2050, significantly contributing to the likelihood of an increase in extreme heat waves and a decrease in extreme cold waves. Heat domes, areas of high pressure that push air toward the ground, trapping it and causing it to heat up and temperatures to rise and linger while preventing rain clouds from forming, once rare, are becoming more common.
Urban Heat Islands
Urban areas are particularly susceptible to heat waves due to the urban heat island effect. This phenomenon occurs when cities absorb and retain heat more than rural areas, leading to higher temperatures. Factors contributing to this effect include concrete and asphalt surfaces, reduced vegetation, and heat generated by human activities. According to the EPA, urban areas can be up to 7°F (4°C) warmer than surrounding rural areas.
Wildfires
The correlation between heat waves and wildfires is evident in the United States, where recent years have witnessed some of the most devastating fire seasons. Elevated temperatures, gusty winds, and prolonged dry conditions create an environment conducive to fire ignition and spread. In 2020, a record 10.3 million acres were burned by wildfires across the United States, according to the National Interagency Fire Center (NIFC). As per the California Department of Forestry and Fire Protection, more than 100,000 acres are scorched in the state in the summer of 2024.
Health Risks
The combination of heat waves and wildfires severely impacts human health. Heat waves pose serious health risks, especially for senior citizens, children, expecting mothers, and those with underlying health conditions. Heat stroke is common during extreme heat events, with symptoms including dizziness, nausea, and confusion.
The Centers for Disease Control and Prevention (CDC) confirms that an average of 702 heat-related deaths occur annually in the United States. The smoke from wildfires can lead to respiratory problems, especially for those with asthma or chronic obstructive pulmonary disease (COPD).
Labor Productivity Losses
Heat waves significantly impact labor productivity, particularly in outdoor and non-air-conditioned environments. Rising temperatures lead to heat stress and fatigue, thereby reducing workers’ efficiency and increasing the risk of heat-related maladies. As per the International Labour Organization (ILO), global productivity losses due to heat stress could reach 2.2% of total working hours by 2030, equivalent to 80 million full-time jobs. The construction, agriculture, and manufacturing industries are especially vulnerable in the United States, which faces substantial economic losses during extreme heat events.
Economic Impact
The economic impact of heat waves is substantial. High temperatures can increase energy consumption as people rely more on air conditioning, increasing domestic electricity costs. Agriculture also suffers, with crops and livestock stressed by excessive heat, leading to reduced yields and higher food prices. As per a report, corn, the most widely produced US crop, is losing value. The United States faces annual losses of $100 billion, worsening to $200 billion by 2030 and $500 billion by 2050.
Furthermore, the financial impact of wildfires is substantial. According to the JEC Democratic Majority’s analysis, wildfires in the United States cause annual losses between $394 billion and $893 billion, equivalent to 2.4% of the US GDP. The indirect costs, including healthcare expenses for respiratory issues caused by smoke inhalation and property loss, significantly add to the overall economic toll.
Mitigation Strategies
Various mitigation strategies are being implemented to combat the effects of heat waves. Some approaches include increasing green spaces in urban areas, using green roofs and reflective building materials, and improving public transportation to reduce vehicle emissions. Heat action plans, including public awareness campaigns and the establishment of cooling centers, are crucial in protecting vulnerable populations. Communities are encouraged to develop emergency plans that include provisions for cooling centers, hydration stations, and public advisories. Individuals should also take precautions, such as staying hydrated, wearing light clothing, and avoiding strenuous activities during peak heat hours.
Heat waves are not confined to the United States; they are a global issue. Countries worldwide, from India to Australia, are experiencing more frequent and severe heat events.