Basic:
Human Health
All living creatures depend on the environment for health and well-being. Earth has provided
dependable sources of food, water, and other natural resources for millennia. Until recently, a
relatively stable and predictable climate has provided the physical safety and comfort necessary
for life to flourish. By changing the composition of the atmosphere, humans almost certainly
impact the environment's ability to support life as it now exists.
Scientists have recently begun to study climate change impacts on human health, yet many of
the findings remain unclear.1 Scientists do know that some impacts will be beneficial. Milder
winters, for example, could result in fewer deaths during the coldest months in temperate
climates. In tropical and sub-tropical regions, extremely high temperatures could reduce the
viability of disease-carrying mosquito populations.2
Overall, however, scientists believe climate change impacts on human health will be largely
negative. Impacts will vary across regions, and communities already burdened by resource
shortages, disease, and disability will face the most severe health impacts. Rural tribes that lack
transportation and healthcare infrastructure, for example, will confront some of the most
difficult challenges. During pandemics, Indigenous Peoples suffer higher infection rates, and
more severe symptoms and death than the general population.3 Indigenous Peoples suffer
diabetes at a rate nearly twice that of general US population, leaving them even more
susceptible to extreme heat, air pollution, and related negative health impacts.4 Understanding
and addressing the specific health vulnerabilities Indigenous peoples will face in tandem with
climate change is essential for guaranteeing their safety and wellbeing.
Tribal health is inextricably linked to the environment and relies on interconnected social and
ecological systems that are being disturbed by climate change.5 As these changes persist, the
health of Indigenous communities and individuals will be impacted through changing land,
water, and food systems. While the physical health of Indigenous Communities may decline
because of impacts from climate change, their mental health will also be negatively affected
should they no longer have access to the land, water, and species they rely on for ceremonies
and spiritual practices. The Yurok Tribe is concerned about the health of their Tribal members
as a result of the declining health of their environment, particularly the rivers they steward.
They recognize that healthy people are born from healthy ecosystems and believe that if their
river and surrounding ecosystems are sick, they too, are sick.6 Tribal views of health differ from
western views of health and take the health of the environment into great consideration.
Infectious diseases
Health officials expect vector-borne diseases-those passed by insects, rodents, and other host
carriers-to pose one of the biggest threats to human health.7 Disease-carrying mosquitoes
require stagnant water and warm conditions to thrive — conditions that will be enhanced by
warmer temperatures and more-frequent storms, both trademarks of a changing climate.
Rodents and ticks in temperate climates will proliferate after mild winters and spread illnesses
such as Lyme disease and tick-borne encephalitis.8 Higher levels of spring runoff lead to
increased food sources for mice. The 1993 hantavirus outbreak on the Navajo Reservation was
linked to heavy snow and rainfall, which helped the rodent population expand to ten times its
normal numbers due to the increase in food availability.9 Under flooding conditions, increased
rodent-human interactions are shown to increase rates of leptospirosis, tularaemia, and viral
hemorrhagic disease.10
Diarrheal diseases are one of the leading causes of death worldwide. In 2017, 1.6 million people
died because of diarrheal disease.11 This symptom of infection caused by a host of bacterial,
viral, and parasitic organisms burgeons during both floods and droughts. Communities living
without consistent access to clean water are especially vulnerable. Preventing not only
diarrheal diseases, but infectious diseases in general will become increasingly more challenging
in a changing climate.
Extreme temperatures
Extreme events such as heat waves and cold snaps may become more deadly as the climate
shifts. Although varying by region, scientists predict an overall increase in heat related mortality
as summertime temperatures increase.12 People with pre-existing conditions and the very
young, old, or frail will be most at-risk. Scientists also expect an increase in deaths, disease, and
injury from other extreme events such as fires and hurricanes.13
Although temperature extremes are becoming more common, some Indigenous Communities
have long since adapted to scorching temperatures. The Tohono O’odham Nation is on the
Southern Border of Arizona, situated in the Sonoran Desert. As temperatures can exceed 110°F
in the summer, they have adapted to the hot, dry environment. The Tohono O’odham people
traditionally constructed wattos – open air shade structures with dirt floors that they
occasionally wet – to combat high temperatures.14 As temperatures in the arid desert become
more intense, the Tohono O’odham people are beginning to rely more on air conditioning to
stay cool. Reliance on air conditioning, particularly in this region, can be problematic as heat
waves and extreme weather can cause electrical failure and blackouts. While air conditioning in
these communities is becoming essential to ensure the safety of their residents, Tribes in
regions facing less extreme temperatures can learn from their practices and model ways of
protecting themselves against extreme heat.
Food security and impacts to traditional medicines and ceremonial practices
A higher rate of crop failure will likely increase malnutrition, especially for children in
developing nations. Regional famines may also swell. Extreme events could cause water
shortages, leading to dehydration, decreased access to potable water, and a host of associated
complications.15
As it becomes more difficult to harvest traditional foods due to crop failure and changing
weather patterns, Indigenous people will rely more heavily on Western food and western food
systems. As is the trend with rural areas, some Reservations are food insecure and located in
food deserts. Combined with a sudden inability to grow healthy foods alone, Indigenous
peoples may resort to consuming the highly processed, non nutritious foods available to them
at nearby convenience stores and gas stations. This will adversely affect their health and may
increase rates of diseases associated with high consumptions levels of processed foods, such as
heart disease, diabetes, and obesity.
In addition to agricultural harvest complications and its effects on the health of Indigenous
Peoples, subsistence harvests will also be impacted. As temperatures warm, deer are migrating
into moose territories and habitats. Deer often carry ticks, which introduce diseases to moose
populations. It is predicted that as a result, deer populations may increase, and moose
populations will decrease.16 Similarly, salmon populations are decreasing due to warming water
temperatures, leaving Tribes without yet another subsistence staple. Salmon, moose, and many
more species are important subsistence foods to Tribes across North America, and should
populations decline, Tribes will be forced to find a replacement.
Air Quality
Air quality will be degraded under climate change, especially in urban areas where greenhouse
gas emissions are most intense. Concentrations of ground-level ozone, a primary component of
urban smog, are rising in most areas. Forest fires and windblown dust from desertification also
negatively affect air quality. Also, studies have shown that allergies caused by pollen worsen as
the seasons warm.17 As seasons become warmer for longer periods of time, the pollen season
itself also extends. This increases the potency of pollen and the duration of its effect on people,
which causes longer allergy seasons and can further disturb those with lung conditions such as
asthma.18 Mold is another common air quality concern that can be exacerbated by climate
change, as it thrives in warm, humid environments – those that will be seen in flooded areas.
Mold, like pollen, can trigger asthma attacks and harm respiratory systems. Changes in air
quality due to climate change will only further health complications faced by those with
respiratory illnesses and those already living in areas with poor air quality.
Mental Health
Mental health complications can be brought on or exacerbated by climate change. Depression,
anxiety, and post-traumatic stress disorder are the most common impacts of climate change on
mental health.19 These impacts can linger for months or years, and the continued effects of
climate change may further delay recovery. Those displaced because of extreme weather
events or other climatic factors are at a higher risk of developing PTSD and general anxiety
disorders than those who do not relocate. Relocation, however, can lessen stressors caused by
a changing climate over time.
The changing climate may also result in the demoralization of entire communities as the land
changes and resources grow scarce, referred to as solastalgia.20 Tribes, still dealing with the
consequences of Euro-American incursions into the Americas, will be forced once again to
adapt to a changing world. Alaska Natives in coastal villages have already been forced to leave
their ancestral homelands to relocate inland as sea levels rise. Traditional hunting practices are
affected as sea ice becomes too unstable for travel and the timing of animal migration changes.
The ranges of plants used for food, medicinal, spiritual, and other purposes are changing.
Reliance on western foods and western food systems will increase as traditional foods become
more difficult to cultivate. Tribal cultural practices may become impossible to continue, and
tribes will once again be forced to adapt to cultural practices and philosophies imposed on
them largely by others.
Climate grief will be rampant across the world as the environment continues to change, but
Indigenous Communities may be impacted much more than others due to their connectivity
with the natural world around them. Globally, we may find solace and healing in climate hope.
Collectively, we may find emotional and spiritual resilience to fully engage with the climate
crisis, ultimately allowing us to consider new ways of life in a rapidly changing world.21
More information
For more information about climate change and human health, visit the World Health
Organization's Climate Change and Human Health page at: www.who.int/health-topics/climate-change