GIJN Guide to Investigating Extreme Heat

Editor’s Note: This guide was prepared by Toby McIntosh, GIJN Senior Advisor, with contributions from many GIJN staff members. Thanks to Alcyone Wemaëre, Andrea Arzaba, Amel Ghani, Ana Beatriz Assam, Sheikh Sabiha Alam, Holly Pate, Pınar Dağ, Gabriela Manuli, Laura Dixon, Benon Herbert Oluka, Majdoleen Hassan, ​​and Tri Joko Her Riadi. Editors of this guide included Nikolia Apostolou, Reed Richardson, and Alexa van Sickle. 

GIJN also appreciates contributions from Joe Lo, a reporter for Climate Home News, and Laurie Goering, the extreme heat editor for Climate Resilience for All.

New records for heat will probably be set this year, eclipsing 2023, which was the warmest year on record, according to Copernicus, the Earth observation component of the European Union’s space program. This continues the alarming trend where the 10 warmest years on record have occurred during the past decade.

The negative effects of higher temperatures can be seen everywhere, offering many opportunities for investigative journalism.

Some headlines have gained worldwide attention. In the summer of 2024, more than 1,300 people died from extreme heat exposure during the Hajj, the pilgrimage to Mecca in Saudi Arabia. In Mexico, howler monkeys became so dehydrated that they fell from trees and died.

The scale of global warming and its consequences are huge.

According to a report by Climate Central, a US non-governmental organization, “6.8 billion people — 78% of the world’s population — experienced at least 31 days of extreme heat” in the 12 months ending in May 2024. And heat waves are expected to claim approximately 1.6 million lives by 2050, according to a January 2024 World Economic Forum report, which also estimated that droughts will cause 3.2 million deaths by 2050.

At the end of a long heat wave in the United Kingdom, people on the dry grass of Greenwich Park look north towards London’s Canary Wharf and the gathering storm clouds. Photo: Alistair Hickson, Flickr Creative Commons

These higher temperatures are caused by higher concentrations of heat-trapping gases in the atmosphere, driven primarily by human use of fossil fuels. These emissions have not only made temperatures hotter, but also led to more intense rainfall, deeper droughts, bigger wildfires, and stronger storms.

GIJN Guide: Ideas, Examples, Resources

This GIJN guide suggests multiple angles to investigating extreme heat as a global phenomenon.

The potential topics include:

• Examining the immediate medical consequences and the readiness of the medical infrastructure;
• Looking at the effects on workers, women, the poor, minorities, and other special populations;
• Investigating how heat is damaging crops, livestock and fisheries, and those who depend on them;
• Asking about how heat affects our societal infrastructure and what is being done to prepare for more heat;
• And much more — including sports, tourism, and biodiversity.

Local and regional news sites are dramatically examining these and many other subjects. There also have been global overviews about heat from major outlets like The Washington Post, Salon, and Rolling Stone.

To be clear, the investigative stories cited below are not news about the weather or stories on the latest scientific reports, although such coverage is critical. Nor is this guide about examining the causes of higher temperatures or the documenting of generalized impacts, such as rising sea levels and shrinking glaciers. (For more tips and resources on the former, see GIJN’s Guide to Investigating Sea Level Rise.) Instead, our examples are journalistic investigations about the effects of rising heat on humans.

Topics to Cover

Medical Consequences

• Immediate health emergencies: heat exhaustion and heat stroke, burns, etc.
• New transmission paths for infectious diseases.
• Respiratory and cardiovascular diseases rising because of wildfires.
• Mental health issues exacerbated.
• Increase in airborne allergens.
• Higher ground-level ozone, which causes higher levels of respiratory disease.
• People who are dependent on medical devices affected by blackouts.
• Measuring deaths from heat.
• Heat affects people with pre-existing conditions, such as the insulin levels of diabetics.
• Heat’s impact on pregnant women and embryos.

Examples

Why Is Cholera Killing Thousands in Southern Africa? – The New Humanitarian

The Killer Stalking Sri Lankan Men – The New York Times

Heat and Pollution Make Pollen More Aggressive and Cause an Increase in Allergies in Summer – elDiario.es (Spain)

Dengue Fever Is Surging Worldwide. A Hotter Planet Will Make It Worse – The Washington Post

For Aging Japan, a Troubling Link between Heat and Dementia – Japan Times

Heat Is Testing the Limits of Human Survivability. Here’s How It Kills – CNN

Persistent Wildfire Smoke Is Eroding Rural America’s Mental Health – Climate Central

Heat in Mexico Causes Record Number of Deaths in 2023 – Quinto Elemento Lab

Dengue Deaths Peak in 2023 in Two Eras, Factors Responsible – BBC (Bangladesh)

How Heat Affects The Brain – The New York Times

Taking The Climate Killers To Court – The Lever

‘When It’s This Hot, Time Stands Still’: Surviving West Africa’s Blistering Heat – The Guardian

Heat Kills Thousands in the US Every Year. Why Are the Deaths So Hard to Track? – The New York Times

Pastoralists in the Ewaso Ngiro river basin in central Kenya dig for water, fearing they will have to begin large-scale cattle destocking if the next rains are poor. Photo: Climate Centre, Flickr Creative Commons

Readiness of Medical Infrastructure

• Are doctors and hospitals prepared?
• Have governments prepared for heat emergencies?
• Have normally cool cities/states/countries understood they are also vulnerable?

Examples

Heat-Related Emergencies Are Soaring in the US Can Hospitals Keep Up? – The New York Times

Heatwave Puts Medicine Efficacy at Risk – The Business Standard (Bangladesh)

SOS from Hospitals: Heat, Outage and Rising Patients Choking Services – The Business Standard (Bangladesh)

Texas Likely Undercounting Heat-Related Deaths – Inside Climate News

Asphalt Burns, Delirium, Body Bags: Extreme Heat Overwhelms ERs Across US – The Guardian

Keeping the Homeless Hydrated in America’s Hottest Big City – Context, Thomson Reuters Foundation

Revealed: Three-Quarters of Prisons in England and Wales Face ‘High Risk’ of Overheating – CarbonBrief

Hot and Alone: How Us Cities Work to Protect Isolated People in Heatwaves – The Guardian

Labor Conditions

• How are various professions being affected: Construction workers, delivery workers, etc.
• Impact on gig workers as well as informal or undocumented workers with fewer labor rights.
• Rising workplace accidents and productivity losses because of heat-related sleepless nights.
• Are employers protecting workers?  What else could they do?
• Are governments doing enough?

Examples

40 Degrees in the Factory: What Happens to Workers’ Health in the Era of Extreme Heat – Reporter Brasil

Saudi Delivery Drivers Bake in ‘Deadly’ Summer Heat – AFP

What It’s Like to Work in One of the Hottest Cities in South America – El Surtidor

The Story of a Heat Death: David Went to Work in his New Job on a French Building Site. By the End of the Day He Was Dead – The Guardian

For India’s Garbage Pickers, a Miserable and Dangerous Job Made Worse by Extreme Heat – AP

The US Has a Plan to Protect Workers from Heat. Employers are Fighting It – The Washington Post

Bangladeshi Garment Workers Fall Ill as Temperatures Soar – Context

The World’s Garment Workers Are on the Front Lines of Climate Impacts – Grist

The “Greenhouse Effect”: How an Oft-Touted Climate Solution Threatens Agricultural Workers – AP

Being a Delivery Driver, a Risky Job on an Increasingly Hot Planet – El Pais

‘You Feel Like You’re Suffocating’: Florida Outdoor Workers are Collapsing in the Heat Without Water and Shade – The Guardian

California Cuts Safety Enforcement as Farmworkers Toil in Extreme Heat – The Los Angeles Times (paywall)

‘Working Here Is Hell’: Latest Death of Farm Worker in 40C Heat Shocks Italy – The Guardian

HEAT HAVOC: Investigating The Impact On Street Vendors – Greenpeace

Digging for water in a dry riverbed in Kenya’s Eastern province. Photo: Flore de Preneuf, World Bank, Creative Commons

Differential Effects on Women, the Poor, and Minorities

• Identifying what areas are most affected by heat and who lives there.
• Exploring which special populations are most at risk.
• The increase in domestic violence during heatwaves.

Examples

‘Thermal Inequalities’ — Cape Town Heat Mapping Reveals Huge Temperature Differences Between Districts – The Daily Maverick

In Extreme Heat, People in Poorer, Urban Neighborhoods Suffer the Most – ecoRI (US)

Heat Inequality ‘Causing Thousands of Unreported Deaths in Poor Countries’ – The Guardian

Slow Wheels of Policy Leave Low-Income Residents of Nashville Feeling Brunt of Warming Climate – Inside Climate News

As US Heat Deaths Rise, Some Landlords Oppose Right to Air Conditioning – Reuters

On Beaches of Gaza and Tel Aviv, Two Tales of One Heatwave – Climate Home News

Heat Waves Can Be Deadly for Older Adults: An Aging Global Population and Rising Temperatures Mean Millions Are at Risk – The Conversation

Luxury or Lifeline? Why a Lack of Air Conditioning Can Be Deadly – The Telegraph

Saudi Visa Crackdown Left Heatwave-Hit Hajj Pilgrims Scared to Ask for Help – Climate Home News

Black Detroit Children with Asthma Hardest Hit by Seasonal Allergies – Bridge Detroit and Climate Central

We Need More Climate-Inclusive Death Data – Nonprofit quarterly

Kenyan Women Pay Harsh Price for Rising Heat: Lost Pregnancies – Climate Resilience

‘I Have to Ask My Husband for Literally Everything’: How a Warmer Climate Is Changing Gender Roles – CNN (India)

‘It’s Torture’: Brutal Heat Broils Texas Prisons, Killing Dozens of Inmates – The Guardian

Agriculture 

• Effects on crops (lower yields, more weeds), and farmers.
• Effects on livestock, and ranchers.
• Effects on fisheries, and people working in the fishing industry.

Examples

‘The Adriatic Is Becoming Tropical’: Italian Fishers Struggle to Adapt to Warm Sea – The Guardian

Quantifying the Impact of Climate Change and Extreme Heat on Rice in the United States – Agricultural and Forest Meteorology

First Heat, Then Floods Wipe Out Farms in Pakistan’s Chili Capital – Dawn

Farmers in Mountainous Areas of Pakistan Feel the Heat – Dialogue Earth

Mangoes are Dropping in Intense Heat, Farmers Are Worried About the Production – Bangla Tribune

Extreme weather hits farmer (in Turkey): Not a single bunch of grapes in 60-ton vineyard – yeşilgazete

Shrimp Farmers Fear Losses for Scorching Heatwave – The Daily Star

The Whistleblower – The Outlaw Ocean Project

Five Charts: How Climate Change Is Driving up Food Prices around the World – CarbonBrief

Climate Change in Beaujolais: Could Gamay Disappear? – Rue89Lyon

A farmer holding two misformed and spoiled corn cobs. The Kondh Adivasis Indigenous community in Odisha, in eastern India, have been impacted by the changing rainfall pattern, which has spoiled corn on a large scale. Photo: Aniket Gawade, ClimateVisuals.org

Infrastructure

• Impact on electrical infrastructure.
• Damage to roads, rails, bridges, dams.
• Surging power and water demand during heat overwhelming supply.
• Lack of planning for energy spikes due to extreme heat.

Examples

Midwest Floods, Widespread Heat Waves Are Undermining US Transportation Systems – Inside Climate News

Stuck Bridges, Buckling Roads — Extreme Heat Is Wreaking Havoc on America’s Aging Infrastructure – The Conversation

The Surprisingly Simple Way Cities Could Save People from Extreme Heat – Grist

Taking a Train During a Heat Wave? Watch Out for ‘Sun Kinks’ – Grist

Sites with Radioactive Material More Vulnerable as Climate Change Increases Wildfire, Flood Risks – AP

Thousands of US Dams May Be Unprepared for Extreme Rain – The New Scientist

Planning and Solutions

• Homes and buildings are still being built using heat-absorbing materials, with big south-facing windows — showing a lack of awareness about the need to shift planning rules.
• Need for coordination between agencies dealing with extreme heat, water supply and firefighting, public transport, and sports or cultural events, etc.
• Need to rediscover older and cooler pre-air conditioning building designs.
• Housing construction in areas with inadequate water supplies is a threat in extreme heat.
• Planting trees in urban areas.

Examples

Cities Are Tackling Rising Heat — But They Have to Avoid a Dangerous Trap – The Guardian

As London Swelters, Adaptation to Heat Extremes Is Now ‘Urgent’ – Climate Resilience for All

Life in a Heat Dome: The American West Is Figuring Out How to Keep Cool – BBC

Can Chief Heat Officers Protect US Cities from Extreme Heat? – Grist

Water ‘Most Dear’ as Heatwave Sets In from Today – Dawn

The Capital Is Full of Trees That Are Not Suitable for the Environment – Prothom Alo

Philippine Heat Has Always Been a Problem — and It’s Going to Get Worse – Rappler

In 2010, ten years’ worth of rain fell in just two weeks in Pakistan, resulting in extreme flooding across much of the country. Relief efforts included providing clean drinking water and sanitation to millions of displaced people. Photo: UK Department for International Development, Creative Commons

Sports

• What is the future of winter sports as record warming takes hold?
• Does the calendar for major sporting events — including the Summer Olympics — need to shift because of rising heat?
• What are the risks to amateur as well as professional athletes, and to school children?

Climate Change Is Putting Athletes and Their Sports at Risk – The Conversation

Athletes Find a Fierce Opponent in Climate Change – CBC

At the Olympics, Heat Can Raise the Danger Bar of Competitions – Inside Climate News

Extreme ‘Heat Dome’ Hitting Olympics ‘Impossible’ Without Global Heating – The Guardian

How Climate Change Threatens the Winter Olympics’ Future – The Conversation

As the World Heats Up, So Does the Debate around Artificial Turf – The New Lede

Innovation to Reduce Risks — What Works and Doesn’t?

• Over-reliance on air conditioning expansion can drive more climate change and be at risk if power grids are overwhelmed or storms hit – and if air conditioning can be unaffordable in extreme heat.
• Importance of green areas, trees, water access in battling heat, with side benefits for biodiversity, mental health, etc.
• Shade structures, cooling spaces, green and white roofs.
• Cooling vests for workers, labor innovations, and heat insurance.

Examples

Extreme Heat Is Impacting Most Americans’ Bills’, Poll Finds – AP

A Third of Hurricane Beryl Deaths in Texas Were Caused by Heat – NBC News

From Insurance to ‘Digital Twins’, Innovation to Cut Heat Risks Is Warming Up – Climate Resilience for All

Eat or Stay Cool? Cities Test Ways to Protect the Poor from Rising Heat – Thomson Reuters Foundation

The Cost of Staying Cool: How Extreme Heat Is Costing Americans More Than Ever – USA Today

Other Impacts

• Economic
• National security
• Tourism
• Wild animals and plants
• Education
• Migration

Examples

Extreme Heat Poses New Challenge for Aid Agencies in Gaza – Context, Thomson Reuters Foundation

How an Era of Extreme Heat Is Reshaping Economies – Financial Times (paywall)

Extreme Heat Poses ‘Real Risk’ to Spain’s Mass Tourism Industry – The Guardian

How Rising Temperatures May Affect Future Elections – Nonprofit Quarterly

Extreme Heat Is Making Schools Hotter — and Learning Harder – The 19th

Tourists Are Feeling the Heat — and Their Bodies May Not Be Able to Catch Up – Inside Climate News

Heat Is Killing Thousands, and Big Events Have Not Adjusted – The New York Times

Extreme Heat Shuts Schools for Millions, Widening Learning Gaps Worldwide – Reuters

Hotter Temperatures Are Causing Trees to Have Heat Strokes –  Sierra Club

Record Salmon Migration Runs Into Hot Water – E&E News

Heat Waves and Droughts Are a Bonanza for Junk Food Companies – The New York Times op-ed

Climate Change Is Filling the Greek Seas with Invasive Species – Efymerida ton Sindakton

Olive trees burn during a wildfire in Greece. Because the olive trees burn from the inside, it’s extremely difficult for firefighters to control and extinguish the fire. When trees burn they release the carbon stored in them into the atmosphere, making wildfire emissions one of the most feared climate feedback loops. Photo: Milos Bicanski, ClimateVisuals.org

Unusual Approaches

The Bureau of Investigative Journalism in the UK sponsored a community-based project to show “how hot people’s houses really get during a heatwave — and what this means for people’s health.” It invited public participation. The approach resulted in stories such as Stifling, Suffocating, Unliveable’: Life in an Overheating Home and Revealed: Escalating Effects of Hot Summers on UK Housing.

Resources

Heat and Health – The World Health Organization.

UNICEF – A report on how many children are affected by extreme heat.

International Labour Organization – “Working on a warmer planet,” a 2019 report.

Climate Shift Index – A global map by the US NGO, Climate Central.

Global Heat Health Information Network – Resources created by an independent, voluntary, and member-driven forum of scientists, practitioners, and policymakers.

Seven Lessons for Journalism in the Age of Extreme Heat – Members and alumni of the Oxford Climate Journalism Network met to explore heat and how to cover it.

World Weather Attribution – “Working with scientists around the world, WWA quantifies how climate change influences the intensity and likelihood of an extreme weather event in the immediate aftermath of the extreme event using weather observations and computer modeling.” See guide for journalists.

Quantifying the Impact of Climate Change on Human Health – A 2024 report published by the World Economic Forum.

Climate Change and the Escalation of Global Extreme Heat – A 2024 report produced in collaboration by Climate Central, World Weather Attribution, and the Red Cross Red Crescent Climate Centre.

Vital Signs – Research on deaths of migrant workers in the Gulf states, including a report called Killer Heat.

Extreme Precipitation in a Warming Climate – A report by the US NGO Climate Central, which also produced a guide, Extreme Weather Toolkit: Extreme Heat.

Extreme Heat and Your Health – US Centers for Disease Control

Countdown on Health and Climate Change: the Imperative for a Health-Centered Response in a World Facing Irreversible Harms – 2023 Lancet report

Persistent Urban Heat – A 2023 study in Science Advances, a journal that regularly publishes scientists’ findings about heat.

Climate Change Impacts by Sector – US EPA. Also by EPA, Climate Impacts on Human Health.

The Impact of Climate Change on Our Health and Health Systems – The Commonwealth Fund

Extreme Heat Is Breaking Global Records: Why This Isn’t ‘Just Summer,’ and What Climate Change Has to Do With It – The Conversation

The Emergence of Heat and Humidity Too Severe for Human Tolerance – Science Advances

Closer Limits to Human Tolerance of Global Heat – Proceedings of the National Academy of Sciences (US)

How Hot Is Too Hot for the Human Body? Our Lab Found Heat + Humidity Gets Dangerous Faster Than Many People Realize – The Conversation

Extreme Heat in Phoenix Could Make Outdoor Work ‘Impossible’ for Nearly Half the Year – Climate Analytics

National Integrated Heat Health Information System

Guidance and Best Practices on Visualizing Extreme Heat – ClimateVisuals.Org

News Sources

Society of Environmental Journalists – See a regularly updated collection of environmental stories. Search for “heat.”

Extreme Heat – A special section in the Guardian

Books

“The Heat Will Kill You First: Life and Death on a Scorched Planet” by Jeff Goodell

“On The Move: The Overheating Earth and the Uprooting of America” by Abrahm Lustgarten

“The Weight of Nature: How a Changing Climate Changes Our Brains” by Clayton Page Aldern

“Slow Burn: The Hidden Costs of a Warming World” by R. Jisung Park

“Warming Up: How Climate Change Is Changing Sport” by Madeleine Orr

“Heatwave: A Picture Book” by Lauren Redniss

Toby McIntosh is a senior advisor for GIJN’s Resource Center, which provides online resources to journalists worldwide. He was the editor of FreedomInfo.org, (2010-2017) a nonprofit website based in Washington, D.C. that covers international transparency laws. He was with Bloomberg BNA for 39 years, has filed numerous US Freedom of Information requests, and has written about FOI policies worldwide. He is a steering committee member of FOIANet, a network of FOI advocates.