Hundreds of millions of people struggled to keep cool amid a sweltering summer heat wave as cities across the U.S. and mainland Europe experienced record-high temperatures. In the U.K., thermometers topped 104 Fahrenheit (40 degrees Celsius) on July 19, 2022, the highest ever recorded.

While all this broiling heat is surely punishing on a personal level, it also has significant impacts on the broader economy.

As an economist who has studied the effects of weather and climate change, I have examined a large body of work that links heat to economic outcomes. Here are four ways extreme heat hurts the economy.

1. Growth takes a hit

Research has found that extreme heat can directly hurt economic growth.

For example, a 2018 study found that the economies of U.S. states tend to grow at a slower pace during relatively hot summers. The data shows that annual economic growth falls 0.15 to 0.25 percentage points for every 1 degree Fahrenheit (0.56 C) that a state’s average summer temperature is above normal.

Laborers in weather-exposed industries such as construction work fewer hours when it’s hotter. But higher summer temperatures also reduce growth in many industries that tend to involve indoor work, including retail, services and finance. Workers are less productive when it’s hotter out.

2. Crop yields drop

Agriculture is obviously exposed to weather: After all, crops grow outdoors.

While temperatures up to around 85 F to 90 F (29-32 C) can benefit crop growth, yields fall sharply when thermostats rise further. Some of the crops that can be hit hard by extreme heat include corn, soybeans and cotton. These reductions in yields could be costly for U.S. agriculture.

For example, a recent study I conducted found that an additional 2 degrees C (3.6 F) of global warming would eliminate profits from an average acre of farmland in the eastern U.S.

A prominent example of this was the collapse of the Russian wheat harvest in response to the country’s 2010 heat wave, which raised wheat prices throughout the world.

3. Energy use soars

Of course, when it’s hot, energy use goes up as people and businesses run their air conditioners and other cooling equipment at full blast.

A 2011 study found that just one extra day with temperatures above 90 F (32 C) increases annual household energy use by 0.4%. More recent research shows that energy use increases the most in places that tend to be hotter, probably because more households have air conditioning.

This increase in electricity use on hot days stresses electric grids right when people depend on them most, as seen in California and Texas during past heat waves. Blackouts can be quite costly for the economy, as inventories of food and other goods can spoil and many businesses either have to run generators or shut down. For instance, the 2019 California blackouts cost an estimated US$10 billion.

4. Education and earnings suffer

A long-term impact of increasingly hotter weather involves how it affects children’s ability to learn – and thus their future earnings.

Research has shown that hot weather during the school year reduces test scores. Math scores decrease more and more as the temperature rises beyond 70 F (21 C). Reading scores are more resistant to high temperatures, which this research claims is consistent with how different regions of the brain respond to heat.

One study suggested that students in schools that lack air conditioning learn 1% less for every 1 degree Fahrenheit (0.56 C) increase in the school year’s average temperature. It also found that minority students are especially affected by hotter school years, as their schools are more likely to lack air conditioning.

Lost learning results in lower lifetime earnings and hurts future economic growth.

The impact of extreme heat on development, in fact, begins before we’re even born. Research has found that adults who were exposed to extreme heat as fetuses earn less during their lifetimes. Each extra day with average temperature above 90 F (32 C) reduces earnings 30 years later by 0.1%.

Air conditioning can help – to a point

Air conditioning can offset some of these effects.

For example, studies have found that having a working air conditioner means fewer people die, student learning isn’t compromised and extreme heat outside during pregnancy doesn’t hurt fetuses.

Not everyone has air conditioners, however, especially in states such as Oregon and countries such as the U.K. that have more temperate climates but have nonetheless recently experienced unusually extreme temperatures. And many people can’t afford to own or operate them. Survey data from 2017 found that around half of homes in the U.S. Pacific Northwest lacked air conditioning. And about 42% of U.S. classrooms lack an air conditioner.

While heat waves are shown to induce more households to install air conditioning, it’s hardly a panacea. By 2100, higher use of air conditioning could increase residential energy consumption by 83% globally. If that energy comes from fossil fuels, it could end up amplifying the heat waves that are causing the higher demand in the first place.

And in the U.S. South, where air conditioning is omnipresent, hotter-than-usual summers still take the greatest toll on states’ economic growth.

In other words, as temperatures rise, economies will continue to suffer.

This is an updated version of an article originally published on Aug. 2, 2021.

Derek Lemoine, Associate Professor of Economics, University of Arizona

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The cost of eggs and bread is soaring – a trend that’s particularly punishing for the poorest Americans.

Average food prices climbed an annualized rate of 10.4% in June, the Bureau of Labor Statistics reported on July 13, 2022. The gains were driven primarily by the cost of groceries, which jumped the most since the 1970s, by 12.2%. Overall inflation was up 9.1% from a year earlier.

These sharp increases have startled consumers, in large part because food costs had been rising moderately for decades.

While all Americans have seen their grocery bills swell, many may not fully appreciate the enormous burden that rising food costs pose for low-income households. The reason is simple: Poor families spend a much larger share of their income on food than the median household.

In 2020, the average middle-income American family spent roughly 12% of its earnings on food. In sharp contrast, poor households spent 27% on food that year.

What explains this enormous discrepancy? The answer begins with a dramatic change in spending patterns among American households during the 20th century, which I learned while researching shifts in commuting practices.

In the 1900s, the bare necessities of life, including food, were enormously expensive compared with today, leaving little room for spending on other goods or services for most Americans, according to a 2006 study by the Department of Labor. On average, American families spent over 40% of their income on food in 1901, 23% on housing and 14% on clothing.

But the relative cost of food and clothing decreased steadily over the next 100 years. By 2002, the two categories represented only 17.3% of a middle-class family’s expenditures and by 2020, the figure had fallen to 14.2%.

The sharp drop in the cost of food and clothing led to a massive reshuffling of family budgets over roughly the past century. As people reduced their spending on these items, they spent more on housing, transportation and insurance. As the country became wealthier, discretionary spending increased, too. Most Americans had more room in their budgets for eating out, televisions and entertainment.

This revolution in household spending largely excluded poor Americans, who continue to devote most of their income to feeding their families and other necessities like shelter. As a result, they are particularly vulnerable to spikes in food costs.

Low-income households devote more than twice as large a share of their budgets to food as middle-income households. As a result, food inflation is around twice as burdensome for families of limited means. But this actually understates the burden of high food costs on the poor because, unlike middle-class families, they have little discretionary spending they can pare back to free up funds for food.

American households are responding to soaring food inflation by eating out less frequently, buying generic brands and consuming less meat. For many, it may be the first time they’ve ever had to be so careful about what they spent on food.

Poor families, however, have long been forced to deploy these tactics to keep food expenditures in check.

An estimated 38 million Americans are food insecure, meaning that they have insufficient means to obtain sufficient food. The concern is, with food inflation rising at the rate it is, more families will face the prospect of being unsure where their next meal is coming from.

David Soll, Associate Professor of History and Environmental Studies, University of Wisconsin, Eau Claire

This article is republished from The Conversation under a Creative Commons license. Read the original article.