Human health in a warming world

The Climate, Health & Equity Brief is GMMB’s take on the latest news on the current impacts of climate change. Subscribe to receive the newsletter in your inbox by clicking here .

Hot Topic: Physical and mental health at risk.?News coverage in recent weeks continues to underscore the influence of climate change on human health and well-being—and shows just how pervasive and far-reaching the impacts are.

In 2023, 2,325 people died of heat-related causes—a year in which dozens of global climate records were broken—and Earth’s climate was the hottest in 125,000 years, according to scientists. Unfortunately, they say, 2024 is "all but certain" to break that record. This summer now has the distinction of the planet’s hottest, with global average temperatures at 1.5°C (2.7°F) above the preindustrial average—the upper limit of what scientists have long warned is a planetary tipping point toward widespread calamity. And those predictions are beginning to bear out.

A sobering assessment from the Union of Concerned Scientists found that more than 99% of the U.S. population has been under at least one extreme heat, storm, wildfire or flood warning since May 1. And the news in recent weeks shows that range of climate-related health impacts continue to increase.

Longer, hotter and more humid summers are contributing to the global spread of potentially fatal insect-borne diseases like West Nile Virus, malaria, and dengue fever, as mosquitos thrive and spread to warming northern regions. In a new study, microbiologists also warn that heat and humidity are likely to increase cases of salmonella—a bacteria that causes diarrhea, fever and stomach pains—as conditions help new strains to thrive on human food sources like fresh produce.

Yet another study warns that wildfire smoke, often caused or exacerbated by climate-related heat and drought, may have adverse impacts on pregnancy. ?These include preterm birth—a major cause of infant death in the U.S. that can also cause lifelong physical and mental health harm to the child.

And then there is the matter of what climate change is doing to our brains. A range of studies show that increased heat impairs emotional regulation and decision-making capacity, resulting in increased aggression and impulsivity. And the existential distress caused by environmental change—particularly for front-line communities—has been linked to heightened rates of anxiety, depression, post-traumatic stress disorder, and even suicide.

Unfortunately, scientists have declared that the long-held global goal of limiting warming to 1.5°C is now unachievable, with a 1.6°C increase emerging as the absolute best-case scenario. This fact means we must all adjust to this new reality, and policies designed to rapidly reduce emissions—and protect people in an increasingly scorching world—must race to keep up.

Human Health

According to researchers, more frequent and intense thunderstorms, air pollution and particulate matter in the atmosphere—all fueled by greenhouse gas emissions—are increasing?lightning strikes ?in India, with related deaths in the country increasing by more than 50% in the last two decades. (Wired)?

According to an?assessment ?from the Union of Concerned Scientists,?99%?of the U.S. population ?has been under at least one extreme heat, extreme storm, wildfire, or flood warning since May 1—and the U.S. has already seen 19 such disasters in 2024, each causing more than $1 billion in damage that together have caused at least 149 deaths. (Los Angeles Times)?

New CDC data show that?heat-related deaths ?in the U.S. rose 117% between 1999 and 2023, with annual deaths peaking at 2,325 last year. (Axios)?

According to public health experts at the CDC and Yale School of Public Health, cases of?insect-borne disease —including West Nile virus, malaria, and dengue fever—are increasing around the world as changing weather patterns shift where and when mosquitos and ticks can thrive. (Axios)?

A new?report ?investigating the impacts of wildfire smoke on pregnant people in Oregon indicates that public health officials are not doing enough to educate them about the health risks—including?preterm birth, birth defects, preeclampsia, and anxiety —or the steps to prevent wildfire smoke exposure. (The 19th)?

In a new?study , microbiologists warn that food poisoning from?salmonella ?will increase as climate change exacerbates heat and humidity, allowing new variations of bacteria to survive and thrive on fresh produce. (Newsweek)?

Phoenix has hit?102 consecutive days of at least 100°F weather —shattering the record of 76 straight days—with no end to the streak in sight as another heatwave bears down on the region. (Axios)

Planetary Health

According to new research, the long-held global goal of limiting warming to?1.5°C is now deemed unachievable ?due to constraints in rolling out green technology and enacting and implementing climate policies, with 1.6°C emerging as the best-case scenario. (New Scientist)

A recent?study ?revealed that?hailstones —which accounted for the highest extreme weather costs in the U.S. in 2024—are expected to increase in size due to ongoing warming, potentially growing to 1? inches or larger and intensifying by 15% to 75% as human emissions worsen. (NBC News)

Equity

A new World Meteorological Organization?report ?found that African nations are?losing up to 5% of their annual GDP ?on average due to the extreme consequences of climate change they face despite being responsible for less than 10% of global greenhouse gas emissions. (AP News)?

Prisoners’ rights advocates are asking a U.S. District Judge to require?the?Texas Prison System —the nation’s largest—to install air conditioning, citing the lack of heat protections for its 123,000 prisoners as cruel and unusual punishment, as temperatures can exceed 110°F within prison walls. (E&E News)?

A new University of Southern California study confirmed that?thawing Alaskan permafrost ?is releasing high levels of mercury into Alaska’s Yukon River, threatening the neurological health of the indigenous people who rely on the river’s fish supply for survival. (High Country News)?

Climate-driven displacement , such as that experienced in Lake Charles, LA—a predominantly black community reeling from multiple extreme weather events—presents challenges for accurate census reporting, potentially leading to undercounting and inadequate representation among impacted populations. (Grist)

Politics & Economy

President Biden announced a historic $7.3 billion investment in?rural electrification , which is expected to prevent nearly 44 million tons of planet-warming emissions annually—equivalent to removing about 10 million gas-powered vehicles from the road. (The Hill) ?

A new?study ?evaluating 1,500 climate policies from the last 25 years found that the?most effective initiatives ?featured a combination of multiple policies that leveraged price instruments like carbon pricing, energy taxes and fossil fuel subsidy reforms rather than one stand-alone policy. (The New York Times)

Skyrocketing energy and water consumption by?AI technologies ?is raising concerns around the globe as the rapidly expanding tech increases electricity costs for consumers, threatens more blackouts, and burns more fossil fuels that contribute to the climate crisis. (Los Angeles Times)?

After a 17-fold increase in electricity demand projections due mainly to new data centers and manufacturing plants, the Georgia Public Service Commission approved buying?non-renewable power ?from companies in Mississippi and Florida—effectively stopping the planned closure of a Mississippi coal-fired power plant. (Grist)

Bridges in the U.S. ?face a heightened risk of failure due to worsening climate change, with extreme heat causing pavement buckling, heavy precipitation eroding foundations, and temperature fluctuations leading to expansion and contraction of the structures. (The New York Times)?

According to an investigation by E&E News,?federal policies ?are putting millions of Americans at risk as they steer billions of dollars away from the nation’s hottest regions and prioritize property protections over policies to protect human lives and health. (E&E News)

Action

Scientists from the University of California at Davis and the Innovative Genomics Institute are leading a $30 million project to edit genes to change the composition of cow stomachs, a move aimed at reducing?methane emissions , which are responsible for 30% of global heating. (The Washington Post)?

For the first time,?wind turbines ?generated more electricity than coal-burning plants across the U.S. for two consecutive months in March and April. (The New York Times)?

South Carolina's?climate resilience strategy , which includes plans to relocate up to 700,000 flood-prone homes, positions the state as a national leader in managed coastal retreats, though less than 10% of eligible residents have signed up due partly to the lengthy buyout process. (Inside Climate News)?

The South Korean Constitutional Court ruled that the country’s greenhouse gas reduction plans are insufficient and unconstitutional and ordered the government to set firm?carbon-reduction targets ?for 2031 and beyond. (The New York Times)

Life as We Know It

Tennis officials at the?U.S. Open ?are deploying preventive measures to protect athletes and spectators from extreme heat, including measuring heat stress, providing cooling areas and misting machines, shifting match times, deploying retractable roofing, and planting more trees. (The New York Times)?

Kimchi ?is the latest food to fall victim to the impacts of rising temperatures as the dish's key ingredient, napa cabbage—grown in cooler mountainous regions during summer—is succumbing to increased heat, with crop sizes now half of what they were 20 years ago. (Reuters)?

Kicker

These?five charts ?highlight how climate change is driving up food prices worldwide due to diseases, extreme heat, and other factors. (Carbon Brief)

"I just don’t think people really grasp how catastrophic the [heat] exposure is going to be even within a decade."

– Justin Schott, University of Michigan Energy Equity Project