Every year, billions of tons of CO2 and millions of tons of methane, the two key greenhouse
gases, are emitted globally into the atmosphere, largely due to the production and burning
of fossil fuels for energy and transportation. This has resulted in a dangerous rise in the
Earth's average surface air temperature compared to preindustrial times.
The combustion of fossil fuels has created a parallel crisis of air pollution, as burning
of these fuels releases massive amounts of respirable airborne particulate pollutants
and toxic chemicals. As many as one billion children worldwide are exposed to high levels
of these pollutants.
Children are particularly vulnerable to severe heat.
Heatwaves during in utero development are associated with increased risk for preterm
birth and low birth weight, hyperthermia and death in infants, heat stress, kidney disease,
and other illnesses in children. In the U.S., heat-related illness is a leading and rising
cause of death and illness in student athletes, and several studies suggest that heat associated
with climate change has an impact on the mental health of children and adolescents.
Weather disasters also pose major challenges for children.
Climate change has intensified major floods and hurricanes that have caused drowning,
physical injury, and traumatic stress in children forced to evacuate, as well as disruption
and loss of education. More than 10 million children are internally displaced by weather-related
disasters each year, mostly in low- and middle-income countries, but even in the U.S.; disasters
displaced over 900,000 people in 2020 alone, many of them children.
Children breathe more air relative to their body weight than adults, and their narrower
airways are more vulnerable to constriction by air pollution and allergens.
Climate change has led to a dramatic increase in forest fires in the western United States
where millions of children are exposed to lung-damaging wildfire smoke each year, and
those numbers keep growing. Exposure to wildfire smoke in utero has been linked to decreased
birth weight and preterm birth, and exposures in childhood are associated with asthma exacerbations,
wheeze, pneumonia, and bronchitis. Children also experience more allergy and
asthma attacks from increased production of airborne pollen and mold as a result of higher
temperatures and rising levels of CO2. Excess moisture from heavy rains and flooding can
lead to proliferation of mold in homes, which can trigger an asthma attack whether or not
the child is allergic. Children have greater nutritional and fluid
requirements than adults, and so are more vulnerable to the kinds of food and water
supply disruptions climate change can cause. Droughts related in part to climate change
have affected much of the world, including the southeastern U.S. In developing countries,
resulting food insecurity has led to a sharp increase in malnutrition, resulting in stunting
of children's bodies and brains with associated behavioral and cognitive problems. Rising
CO2 concentrations has also been linked to a reduction in the nutritional quality of
major cereal crops. Children, especially infants, are most susceptible
to gastrointestinal infection with bacterial pathogens such as salmonella in food and water
which is more frequent at higher ambient temperatures. Children are also more susceptible than adults
to cholera and other infectious diarrheal diseases due to crop and water contamination
from storms and floods. Climate change is increasing the risk of a
number of vectorborne diseases by increasing the duration of the transmission season and
the geographic range of the insect vectors.
Among these vectors are the mosquitoes that carry malaria (anopheles) and dengue (aedes).
The toll is mainly in children in tropical regions; however, small local outbreaks of
dengue have been seen in Hawaii, Florida, and Texas. The aedes mosquito is also the
primary carrier for the Zika virus, responsible for the 2015–2016 epidemic in the Americas,
and cases of local Zika transmission occurred in Florida and Texas in 2016–2017. Transmitted
from a pregnant woman to her baby, the virus causes microcephaly, severe brain malformations,
and other birth defects. This toll on children's health is largely
in developing countries; however, the U.S. has seen a marked increase in Lyme disease
as well, with the highest rates in children.
Air pollution from the burning of fossil fuels exposes children's bodies to particulate pollutants
and other toxicants.
Rapid growth and development in early stages of life make children especially susceptible
to disruption by toxic chemicals and other stressors. Biological defense mechanisms to
detoxify chemicals, repair DNA damage, and provide immune protection are immature in
young children, heightening their vulnerability to psychosocial stress and physical toxicants.
Air pollution is a well-known trigger of asthma attacks in children with the disease, and
is now understood to be a cause of asthma. It is also a risk factor for respiratory infections,
bronchitis, and impaired lung growth and function. Children with higher exposure to air pollution
have more severe asthma symptoms and lower levels of regulatory T cells that help control
it. Air pollution is strongly associated with
increased risks of infant mortality and adverse birth outcomes, affecting millions globally.
These birth complications confer increased risk for lower respiratory infections, other
infectious diseases, and asthma in childhood, as well as long-term intellectual disabilities.
Exposure to air pollutants has also been associated with reduced cognition, attention problems,
ADHD, and autistic traits in childhood, as well as depression and anxiety in children
and adolescents. The toll in children and pregnancy from fossil-fuel
pollution and climate change is large and growing. These consequences disproportionately
affect children in low-income countries as well as in low-income neighborhoods and communities
of color in the U.S., where fossil-fuel infrastructure is often located, and access to adequate health
care can be a challenge in itself.
Awareness of the broad range of health consequences of climate change and air pollution on children,
is essential for securing the health and continued well-being of this young and especially vulnerable
population.