What Should Everyone Know About Heat Waves?

Learn more about heat waves, and get statistics about the impacts of extreme heat on communities around the world.

Heat waves aren’t named like natural disasters and often fail to garner the vigilant attention and planning that people, plants, and animals require to survive.

Yet, the frequency, intensity, and devastating impacts of extreme heat is on the rise, according to the World Meteorological Organization.

Worldwide school closures, crop losses, and the death of fish in huge numbers are among the many adverse impacts of extreme heat.

Here are answers to some of the most frequently-asked-questions about heat waves, along with a few short and long-term solutions that forward-looking communities are enacting to combat extreme temperatures and offer relief in a warming world.

What is a heat wave?

A heat wave is a period of abnormally hot temperatures that falls outside an area’s typical range. Extreme heat must last at least two days or more to qualify as a heat wave.

Are heat waves becoming more common?

Yes. Heat waves are becoming more intense and frequent. 2023 was the hottest year ever recorded, partially due to the cyclical climate pattern El Niño that happens every 6-7 years, which studies now show are being made more frequent and extreme by global heating.

In July 2023, large areas of Mexico, Southern Europe, China, and the US broke many local high-temperature records. In the United States, heat waves are rising dramatically, from an average of two per year during the 1960s to six per year between the 2010s and 2020s.

How do heat waves affect health?

Extreme heat is deadlier than floods, hurricanes, and lightning combined. High temperatures create a cascade of problems for the human body to navigate, including the loss of our ability to control our temperature and enter dangerous heat strokes that can cause permanent disability or death, especially among the elderly, children, outside laborers, and other high-risk populations.

Heat waves worsen cardiovascular and respiratory issues and can even cause kidney damage and symptoms of impaired cognition like reduced concentration, slower reaction times, and memory impairment.

Each year, around 12,000 people die due to heat waves. The World Health Organization estimates that, by 2050, more than 255,000 people could be killed annually from extreme heat waves. Despite already high numbers of deaths, experts predict we are likely undercounting heat-related deaths by six times.

How do heat waves impact the environment?

Heat waves have far-reaching impacts on the environment, straining ecosystem health, natural resources, and biodiversity. Heat waves also amplify the impact of drought, increase wildfire likelihood and hazardous smoke, and cause water insecurity, power shortages, and crop losses. The effects of heat waves on non-crop plants are under-studied but appear to be particularly lethal when coupled with extensive droughts.

How do heat waves impact animals?

When considering the far-reaching impacts of heat waves, it’s important not to forget all the outdoor creatures that cannot come indoors to cool off. Recurring periods of extreme heat are associated with increased psychological stress, reduced reproduction, and a decrease in population sizes. The decrease in wildlife is a crisis in its own right—with wildlife populations plummeting by an average of 69% between 1970 and 2017. Mammals, birds, fish, amphibians, and reptiles are all dwindling as populations of sharks, frogs, and salmon collapse.

How does climate change influence heat waves?

Occasional heat waves have always been a natural phenomenon. However, as the burning of fossil fuels goes unchecked, human-driven climate change makes heat waves far more intense, frequent, and deadly. As Sanne Sevig Davis, Founder of GlobalGiving partner Nature Kids of Siargao, points out:

“Extreme heat is a clear indicator of climate change, which affects our daily life and environment.”

Which individuals are most affected by heat waves?

Heat waves disproportionately affect certain populations. These are some of the groups bearing the brunt of extreme heat:

Elderly people are more susceptible to heat-related illness due to physiological changes that occur with aging.

Children and infants are less capable of regulating their body temperature than adults. In many areas, children walk long distances to school under the scorching sun.

People with pre-existing health conditions are more susceptible to heat-related illness because heat can exacerbate cardiovascular, respiratory, or other chronic conditions and lead to severe complications.

People experiencing homelessness, living in mobile homes, or who don’t have air conditioning cannot escape the heat through their housing.

Farmers and outdoor laborers are at an increased risk of health-related illness and death due to physical exertion and extended time spent in heat.

Minority groups around the world living in areas with a history of structural discrimination often face conditions that exacerbate extreme heat, such as poor urban planning and housing discrimination. In the United States, for example, Black and Hispanic residents have the highest average summer urban heat island exposure while living in neighborhoods with fewer trees and green zones and more traffic.

Pregnant people face an increased risk of health-related illnesses, and high temperatures can pose risks to both a pregnant person and their fetus.

What is the urban heat island effect?

The urban heat island effect, or UHI, is when a metropolitan area is considerably warmer than surrounding rural areas. Heat is created by people, transit, and industries and trapped by skyscrapers, sidewalks, and parking lots.

Some organizations are working to combat this by planting trees in vegatally-scarce neighborhoods to offer shade, air filtration, and invite plants and animals back to the city. Our partners at Association For Women’s Awareness and Rural Development are leading the way in Pakistan with the grand goal of planting one million trees in the communities that need them most.

Learn more about Association For Women’s Awareness and Rural Development.

How are rural communities impacted by heat waves?

Rural communities face a different challenge when it comes to extreme heat: occupational heat exposure. Agricultural workers and those in manufacturing environments can be exposed to dangerous temperatures for prolonged amounts of time. Furthermore extreme heat impacts their livelihoods that depend on crops and livestock.

Factors that exacerbate the impact of extreme heat include reduced vegetative cover, increased soil erosion and degradation, lower soil moisture, loss of ecosystem services like carbon sequestration, and more.

“It is uncomfortable to see the countryside drying up. And up north forest fires are commonly occuring,” said Dr. Jean Talens, Executive Director at Climate Change Network for Community-Based Initiatives.

This community organization works directly with rural farmers in the Philippines who already lost billions in Pesos, or roughly 100 thousand dollars, as temperatures soared to 109° F in early May in Quezon City, Philippines. The nonprofit also organizes youth-led coalitions that set up community pantries featuring organic products, have continuous dialogues with local governments for climate action, and conduct agroecology training.

What countries are most impacted by heat waves?

People living in Heatwave Hot Spots experience extreme heat and climate change more intensely. Today, 40% of the world’s population lives in hot tropical regions, where many endure potentially life-threatening temperatures for at least 20 days a year.

Certain countries are more at risk due to climate, geography, infrastructure, population density, and socioeconomic factors. Generally, tropical and subtropical regions are more susceptible to heat waves, as are areas with large urban areas and limited adaptation resources.

India, Pakistan, Bangladesh, Nigeria, Saudi Arabia, and the Philippines are some of the most at-risk countries for heat waves. One study estimated that heat waves could cost India $450 billion annually by 2050 due to reduced labor productivity, increased energy demand, and health costs.

GlobalGiving has observed a steady rise in the use of ‘extreme heat’ and other related terms since 2006 from our vast archive of donor communications sent from our nonprofit partners. We have predominantly noticed this trend from our partners in Africa and South Asia.

We have also discovered that few organizations exist solely to respond to extreme heat. That said, around the globe more nonprofits are being called into action by rising temperatures with heat-specific-projects.

What are the economic impacts of heat waves?

Heat waves have already cost the world economy trillions of dollars since the early 1990s, according to a Dartmouth study.

Here is a glimpse into the cost of extreme heat:

  • Energy Costs: As heats rise, so do energy bills to cool down hot spaces—resulting in the horrible irony of demanding more of the extractive energy causing more climate heat to stay safe from the heat.
  • Productivity Loss: Due to extreme heat’s impact on the mind and body, outdoor laborers and those working in non-air-conditioned environments are reasonably expected to be less productive or absent from work during extreme heat. Many outdoor–operating businesses also may have to close down during heat waves, which could devastate sectors like tourism, hospitality, and retail.
  • Healthcare Costs: As heat waves lead to a rise in illness, higher medical costs and strains are expected to follow.
  • Infrastructure Stress: Extreme heat can damage roads, railways, and power lines and rack up hefty repair prices. Heat waves can cause power outages due to increased demand for air conditioning, damaging electrical grids, and disrupting transportation networks by causing rail lines to warp and roads to buckle.
  • Agricultural Loss: Plant biologist Carl Bernacchi at the University of Illinois said that “every day of a heat wave, you’re looking at a proportionate decrease in yield.” As crops wilt and sometimes die, farmers face less abundant yields—which also threatens food security in massive ways.

How do heat waves influence food security?

Heat waves pose a direct risk to food security by reducing crop yields, storage, and transportation. One study estimated that a 1°C increase in global temperature could reduce wheat yields by 6%, rice by 3.2%, and maize by 3.2%.

As food production goes down, prices will go up—making it harder for low-income groups and people living in isolated or developing countries to purchase the food they need to survive.

What are the social impacts of extreme heat?

Extreme heat seems to scorch just about everything—including social behavior. GlobalGiving spoke with our nonprofit partner Sanne Sevig Davisr of Nature Kids of Siargao about how extreme heat is rippling through communities in the Philippines.

“On days of extreme heat in Burgos, Siargao, the community faces a relentless and oppressive environment,” Sanne said. “Temperatures often soar above 38°C (100°F) from early morning until late afternoon. The air is thick and humid, making it feel even hotter. By early afternoon, access to tap water disappears as sources run out, leaving us without water for about 14 hours each day. This means no evening showers, no watering gardens, and no brushing teeth.” Sanne also said:

“Daily activities, like going to the market, working, or cleaning, become exhausting and difficult. The town becomes eerily quiet, with life only buzzing during the last hour of sunlight when the heat subsides.”

Sanne is particularly concerned about the impact of extreme heat on the children of Siargao, who often cannot attend school during the day’s peak heat for three hours, even for the ones with air conditioning.

Learn about Nature Kids Of Siargao’s approach to helping children cope with extreme heat.

Are heat waves a disaster?

Yes. Extreme heat becomes a disaster when people and places are not adequately prepared. Extreme heat, however, is simply too deadly to be unprepared for.

As GlobalGiving learns more from our partners and our peers, what we’re realizing is that the standard disaster response model simply does not fit this evolving crisis.

“Unlike floods and fires, no rescue team can be sent when multi-organ failure sets in. We cannot wait for the cameras to start fundraising because the cameras never come. Responding to extreme heat uniquely requires a proactive approach,” said Kelly Wilson, Senior Manager of Strategic Grants, GlobalGiving.

As we expand our disaster work to include extreme heat, our commitment to fund equitable, community-based solutions for those most vulnerable to the deadly impacts of this often invisible crisis is unwavering.

What can I do to prepare for heat waves?

Preparing for a heat wave will look different for everyone. But generally, the recommendation is to stay informed, create an emergency plan, do what you can to stay cool and hydrated, prepare your home, stay indoors, and check in on your neighbors and at-risk individuals in your community and neighborhood. You can also advocate for heat wave early warning systems and support heat wave solutions in your neighborhood.

You can also get involved in more collective efforts to combat climate change, prepare communities for intense heat, and create resiliency by helping restore cities and ecosystems.

What are solutions to heat waves?

When exploring solutions to heat waves, it’s helpful to break the topic up into two categories: immediate action and long-term responses.

Immediate action refers to the disaster response work that communities, governments, and groups do to help people cope with heat waves as they occur.

What are immediate solutions to heat waves?

Public Awareness: Research shows that people tend to feel uncertain about precautions for extreme heat and don’t perceive much personal risk. Nonprofits can lead awareness campaigns to educate communities about the dangers of heat waves, the signs of heat-related illness, and how they can stay safe.
Outreach To At-Risk Populations: During disasters, nonprofits often reach out to at-risk individuals to ensure that everyone in their network is safe and taken care of.
Resource Distribution: People and groups can help each other during heat waves by delivering life-saving materials like fans, blackout curtains, water, and more.

A good example of this is from the Nature Kids of Siargao Association, which recently launched a project on the GlobalGiving platform to bring free drinking water to 5,000 households in northern Siargao Island.

What are long-term responses to heat waves?

Long-term responses to heat waves are the solutions that aim to reduce greenhouse gasses and make sweeping changes to improve local area’s ability to handle extreme heat.

One example of this is our partners over at the Association for Women’s Awareness and Rural Development in Pakistan—who are currently on a mission to plant one million trees in the next five years in an effort to decrease temperatures and enable air filtration in an area hit hard by air pollution.

Here are 10 more ways that communities and organizations can respond to heat waves:
1. Advocacy
2. Regenerative Agriculture
3. City Planning
4. Ecosystem Restoration
5. Planting trees in low-income neighborhoods
6. Passive Cooling
7. Cool Places
8. White Roofs
9. Traditional and Sustainable Architecture

And these are only some of the solutions to extreme heat. You can help communities already dealing with the deadly consequences of extreme heat by supporting organizations bringing down the heat.


Featured Photo: 1 Million Liters of Safe Drinking Water in Mexico by Caminos de Agua

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