As climate change continues to warm the planet, more and more of the people who work outdoors will face “hot days.” Think of it as the opposite of snow days. These are periods when excess heat forces local activities to grind to a halt.
Heat can do more than just make it uncomfortable to be outside. A mix of high heat, humidity, low wind and other weather conditions can make it unsafe to do some jobs, such as farming and construction. People’s health can suffer under these conditions. So will family incomes.
Productivity is the term experts use when measuring the quantity and quality of someone’s work. Lost productivity “is a major consequence of the health impacts of global warming,” says Yu Shuang. She’s a climate scientist in Beijing at the Chinese Academy of Sciences’ Institute of Atmospheric Physics. If heat stress keeps people from working, they won’t be able to earn money. And the impacts of that lost productivity can ripple throughout a country’s economy.
Oliver Andrews is a climate scientist at the University of Bristol in England. Not being able to work, he notes, is especially bad for people who don’t earn much on good days. Having to take even a short climate break from work for excess heat can now rob low-income people of the earnings they need to buy food, to pay for medical care or to cover other costs, he points out. That can tempt people to work in hazardous conditions — even if it ups their risk of illness or death.
In one recent study, Andrews and his colleagues looked at how temperature, humidity, wind and other weather conditions would affect the ability of adults to perform their daily jobs. Those factors combine into a measure of heat stress. It’s known as the wet-bulb globe temperature (WGBT). Anything above a monthly average WBGT of 34° Celsius (93° Fahrenheit) is too hot to work safely for a large part of the month, Andrews says.
On that basis, India, Mexico, Pakistan, Algeria and Chad already face a high risk of work-related heat stress, the team found. But the list would grow as the climate continues to warm. Scientists have been saying many environmental conditions can change dramatically once Earth’s average warming reaches 1.5 °C (2.7 °F) above temperatures typical of a century ago or more. And Earth is closing in on that. Once that temperature threshold is reached, another 15 countries, including Australia, go on the list of places where it often would get too hot to safely work. And the United States and 10 more countries go on after global warming passes 2 °C (3.6 °F) above the old norm.
This study appears in the December 2018 Lancet Planetary Health.
But work productivity can suffer even at lower temperatures. The fall-off can start before the WGBT hits 28 °C (82 °F), notes a report is in the January 2019 issue of Climate Policy.
In many cases, “if workers are less productive, their wages will be lower,” explains economist Sam Fankhauser. He’s one of the report’s authors. He works in England at the London School of Economics. “We know that people’s ability to do certain tasks diminishes when it gets too hot,” he says. “Hard physical work in the heat wears you out quickly. Farmers, construction workers and people in non-air-conditioned factories would need more breaks. This means they would get less work done. And, he adds, when overheated “your cognitive functions are lower.” By cognitive, he refers to our ability to think clearly, perform calculations and make informed decisions.
Yu and her colleagues have looked at how many work days different areas would likely lose in a warming world. They found “a worldwide pattern” of loss in worker productivity. And work days lost to heat wouldn’t happen only in tropical and subtropical areas, she reports. Places like northern Europe and Central Asia will feel the heat as well.
Her group’s study appears in the January 20 issue of the Journal of Cleaner Production.
Not all countries will feel these impacts equally. With a 2 °C (3.6 °F) increase in global temps, low-income countries would have about 2.5 times as many lost work days as wealthier nations. At that point, the average worker in a low-income country would lose about 31 days of work each year. At 3 °C (5.4 °F) of warming, they’d lose about 61 days each year. That’s potentially two full months of lost wages.
How to adapt?
Yu’s team hopes its work will guide policy makers to take action. Educating people about global warming and its consequences can help, says Yu’s co-author Yan Zhongwei. He works with Yu at the Institute of Atmospheric Physics. For example, he notes, England has a “heat wave plan.” It outlines ways for people to stay safer and healthier when really hot weather develops.
But such a plan might not work everywhere. Fankhauser and his colleagues have looked at the effectiveness of more than a dozen steps for adapting to heat stress. The best choice for any particular place will depend a lot on local conditions, they conclude. For instance, changes in people’s working hours can avoid them having to work during the hottest part of the day. If people work the same total number of hours, that might be fine. If they wind up working fewer total hours, though, their incomes would suffer.
More air conditioning is another way to beat the heat. That’s fine if the electricity comes from renewable sources and the electric grid is reliable, Fankhauser’s group notes. It’s not so great if the extra electricity would spew more greenhouse gases into the air. That would make climate change worse. It’s also not a good option if the extra use of electricity strains the ability of power plants to supply what’s needed. Failing power plants could result in electrical blackouts, something that tends to happen more in low-income countries.
And, of course, air conditioning doesn’t turn down the heat for outdoor workers. Many developing countries rely heavily on farming or other outdoor work. So again, Fankhauser notes, poor countries would face a disadvantage.
atmospheric physics This field of meteorology is related to climate science. People who work in this field, called atmospheric physicists, use computers and math to model the properties of Earth's atmosphere that drive weather and climate.
blackout (in energy) The loss of electric power to a broad area, and so named because all of the electric lights in the affected area will blink off when this occurs (unless they have a backup electric generator).
climate The weather conditions that typically exist in one area, in general, or over a long period.
climate change Long-term, significant change in the climate of Earth. It can happen naturally or in response to human activities, including the burning of fossil fuels and clearing of forests.
cognitive A term that relates to mental activities, such as thinking, learning, remembering and solving puzzles.
colleague Someone who works with another; a co-worker or team member.
economics The social science that deals with the production, distribution and consumption of goods and services and with the theory and management of economies or economic systems. A person who studies economics is an economist.
economy Term for the combined wealth and resources (people, jobs, land, forests and minerals, for instance) of a nation or region. It is often measured in terms of jobs and income or in terms of the production and use of goods (such as products) and services (for instance, nursing or internet access).
factor Something that plays a role in a particular condition or event; a contributor.
function A relationship between two or more variables in which one variable (the dependent one) is exactly determined by the value of the other variables.
global warming The gradual increase in the overall temperature of Earth’s atmosphere due to the greenhouse effect. This effect is caused by increased levels of carbon dioxide, chlorofluorocarbons and other gases in the air, many of them released by human activity.
greenhouse gas A gas that contributes to the greenhouse effect by absorbing heat. Carbon dioxide is one example of a greenhouse gas.
grid (in electricity) The interconnected system of electricity lines that transport electrical power over long distances. In North America, this grid connects electrical generating stations and local communities throughout most of the continent.
humidity A measure of the amount of water vapor in the atmosphere. (Air with a lot of water vapor in it is known as humid.)
journal (in science) A publication in which scientists share their research findings with experts (and sometimes even the public). Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.
physical (adj.) A term for things that exist in the real world, as opposed to in memories or the imagination. It can also refer to properties of materials that are due to their size and non-chemical interactions (such as when one block slams with force into another).
policy A plan, stated guidelines or agreed-upon rules of action to apply in certain specific circumstances. For instance, a school could have a policy on when to permit snow days or how many excused absences it would allow a student in a given year.
risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
stress (in biology) A factor — such as unusual temperatures, movements, moisture or pollution — that affects the health of a species or ecosystem. (in psychology) A mental, physical, emotional or behavioral reaction to an event or circumstance (stressor) that disturbs a person or animal’s usual state of being or places increased demands on a person or animal; psychological stress can be either positive or negative.
weather Conditions in the atmosphere at a localized place and a particular time. It is usually described in terms of particular features, such as air pressure, humidity, moisture, any precipitation (rain, snow or ice), temperature and wind speed. Weather constitutes the actual conditions that occur at any time and place. It’s different from climate, which is a description of the conditions that tend to occur in some general region during a particular month or season.
Journal: E. Day et al. Upholding labour productivity under climate change: An assessment of adaptation options. Climate Policy. Vol. 19, January 2019, p. 367. doi: 10.1080/14693062.2018.1517640.
Journal: Yu Shuang et al. Loss of work productivity in a warming world: Differences between developed and developing countries. Journal of Cleaner Production. Vol. 208, January 2019, p. 1219. doi: 10.1016/j.jclepro.2018.10.067.
Journal: O. Andrews et al. Implications for workability and survivability in populations exposed to extreme heat under climate change: A modelling study. Lancet Planetary Health. Vol. 2, December 2018, p. e540. doi: 10.1016/s2542-5196(18)30240-7.