Earlier this year, the U.S. Global Change Research Program released its scientific Climate and Health Assessment which was commissioned by Congress in 1990 in order to study human health impacts associated with global warming and climate change. The report’s summary begins by telling us what we’ve already learned this week on The PediaBlog:

Climate change is a significant threat to the health of the American people. The impacts of human-induced climate change are increasing nationwide. Rising greenhouse gas concentrations result in increases in temperature, changes in precipitation, increases in the frequency and intensity of some extreme weather events, and rising sea levels. These climate change impacts endanger our health by affecting our food and water sources, the air we breathe, the weather we experience, and our interactions with the built and natural environments. As the climate continues to change, the risks to human health continue to grow.


The report, which is part of the larger National Climate Assessment (NCA), breaks down seven consequences of global warming for the planet’s climate and weather to help readers consider the damage being done to people’s health. Trying to summarize each climate impact on human health requires us to re-visit the PediaBlog two years ago this month when we made sense of the landmark 2013-2014 Intergovernmental Panel On Climate Change (IPCC) Fifth Assessment Report. The blog post provides this crucial reminder before we fill in the blanks:

The direct and indirect impacts of global warming and climate change on human health — both present and future — are not hard to grasp. Climate change is a global phenomenon; it affects everyone, but no one more than the poor, the sick, the elderly, and children — especially children.


  • Extreme Heat

Heat-related illnesses and deaths (dehydration, heat stroke, and cardiac arrest) are seen during heat waves, which have been increasing in frequency, duration, and intensity.

  • Outdoor Air Quality

Fine particulate matter and ground-level ozone pollution is worse with hotter temperatures. The American Medical Association reports in this week’s edition of JAMA that 43 million Americans live in areas that exceed EPA standards for fine particulate matter; a third of the world’s population lives in areas that exceed WHO standards. The respiratory effects from air pollution are profound, especially in children with chronic lung conditions like asthma. (According to the CDC, nearly 10% of American children have asthma.) The risk of wildfires has also increased in recent years as a result of warming, leading to even more air pollution that can affect people who live far from the fire.

As reported on The PediaBlog last week, 92% of the world’s population breathes unhealthy air, according to a study conducted by the World Health Organization.

Air pollution isn’t the only factor that makes asthma worse. Higher carbon dioxide levels in the atmosphere leads to higher production of plant-based pollens. Higher concentrations of allergens over longer allergy seasons increase allergic sensitivities and asthma exacerbations. An estimated 14.2 million children in the U.S. visit their physician’s office and another 1.8 million visit emergency departments every year with the primary diagnosis of asthma. Those numbers are expected to increase with climate change.

  • Extreme Events (flooding following stronger storms, for example)

From the Climate and Health Assessment: While it is intuitive that extremes can have health impacts such as death or injury during an event (for example, drowning during floods), health impacts can also occur before or after an extreme event, as individuals may be involved in activities that put their health at risk, such as disaster preparation and post-event cleanup. Health risks may also arise long after the event, or in places outside the area where the event took place, as a result of damage to property, destruction of assets, loss of infrastructure and public services, social and economic impacts, environmental degradation, and other factors. Extreme events also pose unique health risks if multiple events occur simultaneously or in succession in a given location.

  • Vector-Borne Diseases/Infections

The geographic distribution of vectorborne diseases like malaria and Chikungunya (mosquitos) and Lyme disease (ticks) is already spreading as warming occurs in more temperate zones.

Zika virus is just the latest mosquito-transmitted infection whose distribution appears to be climate-dependent.

  • Water-Related Illness

Waterborne diseases that cause severe, often fatal diarrhea in children are also expected to increase as flooding caused by heavy rainfall and rising coastal sea levels infiltrates and overflows private and municipal sewage systems, contaminating food and drinking water supplies.

  • Food Safety, Nutrition, and Distribution

Food stability is already being threatened by encroaching areas of drought on previously arable farmland. Rising coastal sea levels will also encroach on food-producing areas. While the global demand for food is increasing, it is expected that 2% of global food production will be lost each year due to climate change. Undernutrition and malnutrition has always been a scourge undermining human health and, with climate change, both are expected to get worse.

  • Mental Health and Well-Being

Climate-related natural disasters can lead to anxiety, depression, post-traumatic stress disorder, and other often-overlooked psychological problems. There are many recent examples of the psychological effects of natural disasters like hurricanes, tornados, flooding, and wildfires on children and adults witnessing the loss of life, limb, and property, the pain of suffering, and the displacement from their homes.


We also included one more piece of bad news in October, 2014 as we looked at the adverse health impacts from climate change:

  • Social Disruption and War

The IPCC report devotes a chapter to past (Darfur) and present (Syria) conflicts that were influenced (among other factors) by climate change. Future armed conflicts appear to be inevitable as large populations are displaced from their homelands by drought, floods, rising coastal sea levels, infectious diseases, pollution, and war.


We’ll wrap up this series on climate change and health tomorrow and assess whether progress has been made to slow down this runaway train we call global warming.


(Image: Impact of Climate Change on Physical, Mental, and Community Health, USGPRC Climate and Health Assessment — globalchange.gov.)