The Ripple Effects of Climate Change

Around half the world’s population lives in places highly susceptible to climate change.  

The climate emergency is a health emergency, with repercussions that threaten to undo the last 50 years of global health gains.  

As droughts worsen, sea levels rise, and disasters intensify, the myriad health effects are becoming increasingly evident. They include physical injury and death, but also surges in disease and rising food and water insecurity. And marginalized communities — those least responsible for the changing climate — suffer most. 

The impacts are mounting. An estimated 216 million people will be displaced by climate change by 2050 and at increased risk of harm, negative health outcomes, and serious mental health challenges.  

Here’s how climate change compromises our health.  

1. Climate change increases injury and mortality.

Extreme weather kills or injures millions of people every year. Almost all weather-related deaths (90%) occur in low-income countries — places where infrastructure and health care are limited and health systems are less prepared.  

Extreme heat is one of the most hazardous consequences of the climate crisis. In 2020, heat exposure led to around 356,000 deaths worldwide. This death toll will increase as temperatures continue to rise. Older populations are particularly vulnerable — heat-related deaths among people over 65 have already risen by 85% since 1990. The average person currently faces 86 days of dangerously high temperatures each year, and as heatwaves become more frequent and severe, fatalities and heat-related illnesses will climb. 

It’s predicted that by 2030, undernutrition, malaria, diarrhea, and heat stress induced by climate change will cause 250,000 more deaths each year.  

2. Climate change increases the risk of infectious disease.

The risk of infectious outbreaks is dangerously high in the aftermath of disaster. When water systems are compromised and homes are destroyed, water-borne illnesses like cholera and vector-borne diseases like malaria thrive — especially in crowded and unsanitary shelters.  

While deaths from physical injuries generally occur within the immediate hours and days after the event, deaths due to infectious and parasitic diseases peak one to two months later.  

Rising temperatures are also leading to upticks in vector-borne diseases like malaria and Dengue fever. Global incidence of dengue has broken records this year, with countries in the Americas reporting the highest numbers of cases in recorded history. The fight against malaria is at a standstill, as case numbers increase and countries like Nigeria and Mozambique experience a resurgence of the disease.  

“As the climate crisis persists, we are bracing up for a surge in temperature-related health challenges, including Dengue and malaria. This underscores the critical importance of ramping up community health education initiatives and providing proactive training of health workers on the symptoms and treatment of vector-borne diseases as they expand into new geographical areas.”

–Dr. Uche Ralph-Opara, Chief Health Officer for Project HOPE

Climate change is also linked to increases in HIV. In Zambia, we’ve seen severe drought lead to an increase in HIV transmission, as our program participants are unable to take their medication without access to clean water or food. A lack of food has also forced people to move in search of fertile land, which has disrupted access to health care. 

“I sometimes miss taking my medicine because I have not eaten,” said Jane, a 43-year-old mother of three. “I find it difficult to make clinical visits as I work to find extra food for my family.” 

3. Climate change leads to food insecurity.

Climate extremes are major drivers of global food insecurity and malnutrition. 

Extreme weather has a significant impact on agricultural production, water availability, and food distribution. Climate events like droughts and floods destroy crops, disrupting production and jeopardizing food supply. Higher temperatures also increase the likelihood of bacterial growth and food contamination. 

In 2021, an estimated 127 million more people were suffering from moderate or severe food insecurity as a result of heatwaves, droughts, and other climate-related events compared to the 1981-2010 average.  

4. Climate change triggers noncommunicable diseases.

Climate change doesn’t just influence the spread of infectious diseases – it also triggers the development of chronic illnesses, the world’s number one killer.  

Research from the University of Hawaii shows that the climate crisis has exacerbated more than half of all known diseases. 

There are many ways climate change contributes to the prevalence of noncommunicable diseases. Extreme heat increases the likelihood of cardiovascular disease, such as heart attacks and strokes. Exposure to air pollution increases the risk of respiratory and cardiovascular disease, cancer, and diabetes, and is linked to more than 4 million premature deaths each year. Droughts and floods create scarcity in nutritious food which leads to obesity, diabetes, and hypertension. 

5. Climate change harms mental health.

Exposure to climate events increases the risk of anxiety, depression, and post-traumatic stress disorder (PTSD). After Hurricane Katrina, nearly half of survivors experienced some form of anxiety or mood disorder, with one in six developing PTSD.  

Children are especially likely to experience long-lasting psychological distress.   

Those who endure and survive climate emergencies travel a long road to recovery. They may experience the loss of a loved one; the loss of a home; limited access to water, food, and medication; or the loss of their livelihood and education, all of which lead to increases in levels of stress and anxiety. Research has shown increases in suicide rates during extended periods of extreme heat and after major disasters. 

“We are seeing a higher risk of burnout, anxiety, and other mental health issues among health care workers in regions of the world that experience extreme weather events. In areas prone to wildfires, for example, health care workers report higher levels of burnout and emotional exhaustion.”

–Dr. Uche Ralph-Opara, Chief Health Officer for Project HOPE

6. Climate change deepens health inequities.

Climate change exacerbates existing health inequities, taking a disproportionate toll on marginalized and low-income communities. This includes newborns and children, women, ethnic minorities, migrants and displaced people, older populations, Indigenous Peoples, and individuals with pre-existing health conditions. 

For example, women and girls face increased threats of violence and abuse in the context of disaster, and reproductive and maternal health outcomes decline when food insecurity, exhaustion, heat, and waterborne diseases are at play. 

Health inequities between populations will continue to deepen if greater action isn’t taken. It’s predicted that by 2050, 200 million people will need humanitarian assistance to recover from climate disasters – double the number of people who need aid now.  

To learn more about Project HOPE’s work in the intersection of climate and health, click here.