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  • Writer's pictureLilla Schottner

How global warming and climate change affect human health?

Updated: Nov 1, 2022

Environmental Field Study at the University of the District of Columbia. (2019)


This paper argues that climate change will have a broad range of direct and indirect impacts on health during this century. The global temperature is rising; hurricanes are getting stronger, heavy rains and longer droughts, wildfires, and some other kinds of severe weather—are changing. Extreme weather events can lead to fatalities, injuries and mass migration, and competition for resources (water, food). Many areas around the globe are already experiencing health threats. The impacts will increase, like mortality due to stronger and longer heat waves created by urban smog. Air pollution, air quality impacts: respiratory, cardiovascular and increase of cancer, caused by burning fossil fuels (coal, oil, and natural gas) rising the CO2 levels. Malnutrition is because by compromised food growing habits and lack of access to water or water-related illnesses. Over-use of herbicides and pesticides due to food scarcity. Changing patterns of infectious and insect-borne diseases (Estabrook, 2011).

Quoting from the report on the management of the health effects of climate change: “Climate change is the biggest global health threat of the 21stcentury.” (Romm, 2018, p.110)!


What is Climate Change, and what causes it?

The difference between climate and weather: the weather is what occurs day to day, and climate is an atmospheric condition measured in the long term, centuries, or even longer. Scientists have been collecting evidence, observing, and analyzing deviations in temperature at different locations worldwide for decades. Their findings show that since the Industrial revolution of 1850, humans have been emitting heat-trapping Green House Gases into the atmosphere; therefore, the earth is warming at an unprecedented rate. When solar radiation hits the planet's surface and strikes dark water or land, it gets absorbed; it is reflected into space when it strikes snow or ice. The earth's atmosphere is full of gases; these gases absorb some radiation coming from the surface, rapidly warming it. Scientists measure Carbon dioxide (CO2) in parts per million (ppm) in the atmosphere. Before the industrial revolution, this number was 280 ppm; after discovering oil and coal, this number started to rise; today, it is 400 ppm and increasing by two ppm per year (Robertson, 2017).

Top scientists are proving to the world since1988, since the formation of the Intergovernmental Panel on Climate Change (IPCC), that climate change is caused by humans, our over-consumption, energy consumption, eating and driving habits by burning fossil fuels and adding carbon dioxide (CO2), methane (CH4), nitrous oxide (NO2) and other greenhouse gases to the atmosphere causing the earth to warm to levels which will make the planet not livable for humans and other species. In the next century, people will face the following problems:

1. Temperature-related illnesses

2. Air quality impacts

3. Extreme events

4. Vector-borne diseases

5. Water-related illnesses

6. Food safety, nutrition, and distribution impacts

7. Mental health and well-being issues

8. Population migration

1. Temperature-related illnesses

The growing concentration of greenhouse gases in the atmosphere can lead to extreme temperatures. Higher temperatures over an extended time can cause a more significant evaporation increase in air temperature, which can cause droughts. Droughts that last three decades are called megadroughts. Researchers have linked one of those megadroughts to what destroyed the Anasazi or Pueblo Peoples in the Colorado Plateau in the 13thcentury (Romm, 2018). The chart below shows that extreme heat conditions can result in illnesses, including heat cramps, heatstroke, and heat exhaustion.

Exposures to high minimum temperatures may also reduce the ability of the human body to recover from high daily maximum temperatures (Friis, 2016). Some parts of the earth will experience extreme cold weather conditions, where people will face hypothermia, frostbites, respiratory diseases, cardiovascular diseases, and death.

2. Air Quality Impacts

Climate changes can impact air quality through three pathways: outdoor air pollution, aeroallergens, and indoor air pollution.

Outdoor: Author Bill McKibben in his book Falter claims that, currently, New Delhi’s air pollution is the worst in the world, and a study found that 4.4 million children in Delhi have lung damage from breathing the air. “Around the world, pollution kills nine million people a year, far more than AIDS, malaria, TB, and warfare combined” (McKibben, 2019, p. 26). In China, a third of yearly deaths are blamed on smog, and by 2030, it can claim a hundred million worldwide. There is also evidence that climate change will increase the frequency and intensity of wildfires. Wildfires emit fine particulate matters and ozone gases that, in turn, increase the risk of chronic and acute cardiovascular and respiratory health symptoms and premature deaths (Romm, 2018). The chart above explains the relations between rising temperatures and ozone-related deaths in the United States.

Aeroallergens: Climate change has also led to higher pollen concentration and a more extended pollen season. Greater concentration of CO2 together, higher temperatures, and changing precipitation increased the quantity of pollen in the air. This increases allergic sensitization, hay fever, sinusitis, hives, and asthma attacks. Especially vulnerable are children and people constantly exposed to it.

Indoor air: In some parts of the world, for example, in Australia, people use wood heaters in their homes. Burning firewood produces methane and black carbon particles. According to the EPA, inhalation of black carbon can cause respiratory and cardiovascular diseases, congenital disabilities, and cancer. Black carbon also contributes to climate change (Robinson, 2011).

3. Extreme Events

Extreme events like precipitations, coastal inundations, hurricanes, droughts, and wildfires are projected to increase in frequency and intensity according to “the third National Climate Assessment (NCA)” (Friis, 2019).

Due to climate change, hurricanes, cyclones, coastal storms, and flooding from stronger precipitations are expected to increase in some parts (see chart below). Therefore, we can expect increased exposure to health hazards and health impacts, such as drowning and death during floods and storms. The most vulnerable will be the elderly, children, pre-existing conditions, disabilities, and people who rely on medical equipment. The sea level had also risen by about eight inches since 1880 when the record-keeping began. In addition, it can grow several feet in the next fifty and one hundred years (six to seven). Such a rise can make coastal cities ungovernable and create mass migration (Goodell, 2017).

Droughts in the southwest the United States are expected to be longer. The health impacts could be reduced water quality and quantity, worsening air quality, infectious diseases, and mental health problems. Longer and stronger wildfires are already occurring in the American West; fire season, on average, is seventy to eighty days longer than it was in the seventies (Kodas, 2017). Wildfire smoke contains carbon monoxide, particulate matter, and volatile organic compounds, significantly reducing air quality (Romm, 2018). Health risks include death, injury, inhalation related, and mental illnesses.

Extreme events will also cause disruptions in essential infrastructures, including power lines, water systems, communication and transportation systems, and emergency responders (Ella, 2016).

4. Vector-Borne Diseases

Vector-borne infection is an interaction between the infectious agent and the human host on the one hand and the vector on the other. It spreads by biological transmission, which refers to the transmission of the infectious agent to a host by the bite of a blood-feeding vector, as in malaria (Friis, 2019).

Few examples of vector-borne diseases:

Bacterial: Anthrax, Lyme disease, Plague, and Salmonellosis.

Viral: Dengue fever, Human monkeypox, Influenza, Avian influenza, Swine flu, West Nile virus, Yellow fever, and Rabies.

Parasitic: Leishmaniosis, Malaria, Trichinellosis and Giardiasis (Friis, 2019)

Climate change will have short- and long-term impacts on disease transmissions.

A new study in 2018 by the University of Colorado found that pests are thriving in a new

heat, causing seven hundred thousand deaths annually (McKibben, 2019).

Tropical climates like in Africa, Southeast Asia, and Central and South America are favorable to most major vector-borne diseases, including malaria, yellow fever, and tick-borne hemorrhagic fevers. These organisms have different sensitivities to temperatures and precipitations (Bulletin of WHO).

Rising temperatures and increasing rainfalls in the US and Europe contribute to migration and the growth of the mosquito population. Increased precipitation can increase the number of breeding sites for vectors such as mosquitos and ticks. The dense vegetations also give shelter and food availability to vectors, leading to population increase and, in turn, disease outbreaks.

Deforestation to create new human settlements or agricultural sites can increase the temperature and create breeding sites for malaria. According to the Centers for Disease Control and Prevention (CDC), malaria is found in hundred countries, putting fifty percent of the world’s population at risk (Friis, 2019). By 2050, seventy percent of the world’s population will live in major cities, and Dengue fever is an urban disease. Cities with poorly managed water control and waste systems will face these problems.

5. Water Related Problems and Illnesses

Across the United States, climate change will affect fresh water and increase people’s exposure to water-related illnesses. A few examples of waterborne diseases are cholera, E. coli, and the hepatitis A virus. They can cause severe diarrhea, dehydration, fevers, and cramps. The most vulnerable groups are children, the elderly, and patients undergoing chemotherapy or who have HIV/AIDS (Frees, 2016).

Other problems like runoff from city streets, lands, and factories are major contributors to water contamination. As the author, Robertson, states, “Runoff from pesticide applications and factory/farms sewage introduce pollution in the form of chemicals, antibiotics, and pathogens to lakes and rivers” (Robertson, 2017, p. 232). These chemicals kill all aquatic life on their way, creating dead zones in rivers, lakes, and seas.

By 2050, there will be more than nine billion people living on Earth, overshooting its carrying capacity (Robertson, 2017). Seas cover 70 % of the Earth’s surface, but only 0.01% of the world’s water is usable for human consumption. Water scarcity and water stress will be a significant problem for humanity in the following decades, especially in sub-Saharan and North Africa, Saudi Arabia, and the Persian Gulf countries.

The oceans are carbon sinks; they absorb about 93 % of the extra heat from burning fossil fuels. Carbon dioxide is heating and acidifying the seas, killing many vital species, reducing diversity, and eventually destroying ecosystems. In a 2013 report to the United Nations, scientists stated: “the oceans, over the course of the century, would become hot, sour and breathless.” This situation can create significant food shortages in the following decades.

6. Food Safety, Nutrition and Distribution

Climate change will affect food security by disrupting food availability, distribution, and nutritional value. Currently, agriculture occupies 35 % percent of the Earth’s land surface. In the 1960s, the green revolution introduced fertilizers, pesticides, irrigation, and hybrid seeds that damaged soils, waters, and ecosystems (Robertson, 2017). The frequency and intensity of some weather patterns will increase the disruption of food distribution by damaging infrastructure or slowing down food transportation. For example, U.S. rivers and canals carry a third of the world’s soy and corn, which were disrupted before because of flooding (McKibben, 2019). This can lead to food damage, spoilage, and contamination, limiting access to safe food. Rising temperatures will result in longer growing seasons with more pest populations; therefore, increased use of pesticides will be the norm, leading to pesticide contamination in humans.

As the ocean’s temperatures rise, so will the potential for fish to uptake higher mercury concentrations. Because of bioaccumulation, the mercury could end up in the human food chain, causing severe health problems, including toxicity to the nervous, digestive and immune systems (WHO).

Many studies have shown as Carbon dioxide (CO2) continues to rise in the atmosphere, the levels of protein and minerals (calcium, iron) in crops including wheat, rice, barley, and the potato will be lower, and the levels of carbohydrate will be higher (Robertson, 2017). Researchers have grown grains in the expected CO2 levels later in the century and found that the percentage of minerals and protein dropped by eight percent. In the developing world, where most people rely on plants for their protein, this can cause protein deficiency (McKibben, 2019).

7. Mental health and well-being

According to many studies, people exposed to natural disasters experience stress, anxiety, and severe psychological harm. As weather-related events such as hurricanes, droughts, floods, and wildfires continue to rise, so will the number of impacted people. The elderly, children, women (pregnant and postpartum women), people with preexisting mental illnesses, and the homeless are at higher risk for distress. Communities living close to the disaster areas are also at increased risk. The elderly and people who take prescription medications will also be at higher risk from extreme heat exposure.

8. Population Migration

Climate change will affect the most vulnerable, the very young and the very old, communities of color and low-income, indigenous populations, immigrants, pregnant women, persons with disabilities, and persons with chronic and preexisting conditions. We can also expect “large-scale population migration and the likelihood of civil unrest” (Romm, 2018, p.110). According to the International Organization for Migration (IOM), by 2050, we may see two hundred million climate refugees coming from Africa, South Asia, and Latin America, which can destabilize entire regions, as we have seen how refugees coming from Syria poisoned the politics in Europe (McKibben, 2019).


Unfortunately, the climate change deniers also believe that global warming is a hoax. There is a difference between a denier and a skeptic: “Proper skepticism promotes scientific inquiry, critical investigation and the use of reason in examining controversial and extraordinary claims; it is foundational to the scientific method. On the other hand, denial is the rejection of ideas without objective consideration” (Romm, 2018, p.197). In the U.S., climate change became politicized due to a climate change denial activism of the conservative Republican Party, and they receive financial support from the fossil fuel industry. In 1946, the leading oil companies had created a “Smoke and Fumes Committee”: their goal was to use science and create public skepticism to prevent environmental regulations; they funneled millions into misinformation campaigns. Similar to the ones Tobacco companies spread about smoking and its cancer-causing debate. Exxon Mobil, for example, has known since 1957 that the burning of fossil fuels has caused global warming.

Author Joseph Romm in his book Climate Change claims that the Koch Industries, run by the billionaire brothers Charles and David Koch, spent more than $48.5 million from 1997 to 2010 to fund disinformation. From 2005 to 2008, Exxon Mobil spent $8.9 million on the climate change denial organizations. Dr. Wei-Hock “Willie” Soon is a Malaysian aerospace engineer who didn’t have any training in climatology, had taken more than $1 million from Exxon Mobil and the Koch Industries to spread misinformation, stating that the humans are not the primary cause of global warming, without disclosing that conflict of interest in his scientific papers (Romm, 2018). The Trump administration is as well very anti-science. The National Climate Assessment, which details the future impacts of global warming on the United States, was released on Black Friday, hoping that no one would notice it. The assessment confirms that climate change poses a significant threat to the nation, and its effects are already being felt. For example, the fires in California were not caused by inadequate leaves raking (Trump) but by global warming. As author McKibben in his book Falter states that “Politicians who don’t’ wish to deal with the issue of global warming often say, “The climate is always changing the earth will be fine; it is humans who are in trouble” (McKibben, 2019, p.66)

There is so much evidence that heatwaves will last longer and cover more significant regions. Climate change makes weather patterns, including droughts, likely to get stuck or blocked, called blocking patterns (Mann, 2016). Nevertheless, the Trump administration and its allies in Congress do and will ignore this. Denying climate change became a Republican principle, rooted in ego, opportunism, and greed.


Suppose we continue business-as-usual, burning fossil fuels (oil, coal) and doing nothing about our changing climate. In that case, the projection for the environment for the next fifty years or the next century is very alarming! We will experience the high-temperature rise, more extended droughts, and dust ball conditions in Southern Europe and in the Southwest of the United States and areas of the world that are overpopulated and heavily farmed. There will be mega-droughts lasting more than three decades. This will also lead to mass extinctions of flora and fauna. We will also experience extreme weather conditions, like major hurricanes, floods, and wildfires. The seas are the planet’s carbon sinks, absorbing CO2 and other greenhouse gases, warming and expending its surface, causing sea-level rise. By 2050, we can experience a one-foot increase and two feet per decade after 2100. The US East Coast is already experiencing a faster sea-level rise than the rest of the world. Harold Wanless, chair of the University of Miami’s Geological Sciences department, told National Geographic in 2013: “I cannot envision Southern Florida having many people at the end of this century,” and in 2014, he said, “Miami as we know it today, is doomed. It is not a question of if. It is a question of when” (Room, 2018, p.100). Hurricane Sandy hit New York, and Hurricane Katrina hit New Orleans; these magnitudes of storm surges will become a norm by the mid-century, forcing millions of people to relocate.


Hypocrisy – “Thy Name Is Climate Change Denial”, The Madhouse Effect, 2016, doi:10.7312/mann17786-008.

Bella, Hassan. “Global Warming and Health: Still Not Too Late.” Saudi Journal of Medicine and Medical Sciences, vol. 4, no. 2, 2016, p. 69., doi:10.4103/1658-631x.178273.

“Chapter 3, pg 94.” Green Trends in Insect Control, by Óscar López and José G. Fernández- Bolaños, RSC Publishing, 2011.

Estabrook, Barry. Tomatoland: How Modern Industrial Agriculture Destroyed Our Most Alluring Fruit. Andrews McMeel Publishing, LLC, 2012.

Friis, Robert H. Essentials of Environmental Health. Jones & Bartlett Learning, 2019.

Goodell, Jeff. The Water Will Come: Rising Seas, Sinking Cities, and the Remaking of the

Civilized World. Back Bay Books / Little, Brown and Company, 2018.

Greenway, A.r., et al. “Description, Evaluation, and Sensitivity Analyses of Principal US EPA Air Quality Prediction Models.” 1980, doi:10.2172/7061297.

Harvey, Mark L., and Paul A. Bell. “The Moderating Effect of Threat on the Relationship between Population Concern and Environmental Concern.” Population and Environment, vol. 17, no. 2, 1995, pp. 123–133., doi:10.1007/bf02208384.

Hay, S. I., et al. Global Mapping of Infectious Diseases: Methods, Examples and Emerging Applications. Elsevier, 2007.

Healey, Justin. Extreme Weather and Natural Disasters. Spinney Press, 2012.

Hopke, Philip K., and David D. Cohen. “Editorial.” Atmospheric Pollution Research, vol. 2, no. 2, 2011, p. 121., doi:10.5094/apr.2011.015.

Kim, Ella J. “U.S. Global Change Research Program: The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment.” Journal of the American Planning Association, vol. 82, no. 4, 2016, pp. 418–419., doi:10.1080/01944363.2016.1218736.

Kodas, Michael. Megafire: the Race to Extinguish a Deadly Epidemic of Flame. Houghton Mifflin Harcourt, 2017.

Lytle, Mark Hamilton. The Gentle Subversive: Rachel Carson, Silent Spring, and the Rise of the Environmental Movement. Oxford University Press, 2007.

Mann, Michael E., and Tom Toles. The Madhouse Effect: How Climate Change Denial Is Threatening Our Planet, Destroying Our Politics, and Driving Us Crazy. Columbia University Press, 2016.

McKibben, Bill. Falter: Has the Human Game Begun to Play Itself out? BLACK INC, 2019.

Rauh, V A., et al. “Impact of Prenatal Chlorpyrifos Exposure on Neurodevelopment in the First Three Years of Life Among Inner-City Children.” Epidemiology, vol. 17, no. Suppl, 2006, doi:10.1097/00001648-200611001-00247.

“Research Watch: Exxon Valdez PAHs.” Environmental Science & Technology, vol. 31, no. 3, 1997, doi:10.1021/es972154t.

Robertson, Margaret. Sustainability Principles and Practice. Routledge, 2017.

Robinson, Dorothy L. “Australian Wood Heaters Currently Increase Global Warming and Health Costs.” Atmospheric Pollution Research, vol. 2, no. 3, 2011, pp. 267–274., doi:10.5094/apr.2011.033.

Romm, Joseph J. Climate Change: What Everyone Needs to Know. Oxford University Press, 2018.

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