Taking Our Temperature

By John Stoddard, Health Care Without Harm’s Healthy Food in Health Care Program on March 4, 2014

The effects of climate change on public health and our food.

There is an interdependent relationship between healthy people and a healthy environment. Polluted air and water, for example, do not affect ecosystems in isolation, but are wide-reaching, impacting the health of the simplest organism to the most complex.

Agriculture’s Climate Footprint

Agriculture is not only vulnerable to climate change, but it has a significant climate footprint. Our industrialized food system relies on massive inputs of petroleum-based resources in the form of fertilizers, pesticides, herbicides, and fuel for farm operations, processing, and transportation —making the current system unsustainable given the climate crisis we are facing. Livestock production, for instance, is one of the largest sources of greenhouse gas emissions, namely methane and nitrous oxide, contributing approximately 18 percent of the global greenhouse gas burden, according to the Food and Agriculture Organization of the United Nations. It is imperative that how we produce food must change in order to ensure our long term food security and health.

Climate change is no exception. Climate change is not just a matter of melting glaciers and stranded polar bears, but a looming public health crisis, and is beginning to be discussed as such. Health organizations, such as the American Medical Association and the American Nurses Association, environmental non-governmental organizations, the Centers for Disease Control and Prevention (CDC), and even the White House, are now framing climate change in a public health context. Given that health professionals will be on the frontlines dealing with the health impacts from climate change, there is concerted effort within the health care sector to educate communities about the issue and to try and mitigate the effects of climate change.

Health Impacts of Climate Change

We have already observed the health consequences of extreme weather—unusually high temperatures have led to increased incidences of heat stroke and more powerful storm systems that leave populations displaced and more vulnerable to illness. Climate experts predict that extreme weather will increase as climate change progresses, as will the associated health threats.

The health impacts of a changing climate are nuanced and complex because higher temperatures can tip an ecological balance, triggering multiple reactions that affect health. For example, a heat wave can worsen ground-level ozone pollution, while higher temperatures may increase ragweed pollen, and promote infectious diseases that are sensitive to temperature.

Changes in our Food System

Accessibility to quality food is essential for good health. Yet, food security will be threatened as the earth warms and changes occur in crops, livestock, and fisheries production.

While increased concentrations of carbon dioxide in the atmosphere may improve yields for some crops in some locations in the short term, accompanying effects such as drought and extreme weather can offset this benefit. Crops like apples and many stone fruits require a minimum period of cold weather for the trees to blossom. Livestock are vulnerable to heat waves, suffering loss of life, reduced fertility, and reduced milk production. Increased prevalence of parasites and diseases also affect livestock, and reduce the quality and quantity of food and pasture. Fisheries face issues due to increasing temperatures—many species have certain and delicate temperature requirements in which they can spawn and survive.

Reducing the Impact of Health Care and Preparing for Climate Change

Understanding these potential health threats is key in preparing for climate change, and also serves as a motivating factor for mitigation efforts. Clinicians and the health care sector as a whole can act now to reduce the threat of climate change.

The EPA estimates that 30 percent of the health care sector’s current energy use—or $1.95 billion—could be reduced without sacrificing quality of care through a shift toward energy efficiency and renewable energy sources. There are several resources available for health care facilities to reduce their climate impact:

Categories of health impacts from climate change:

  1. Heat Waves The frequency and duration of heat waves are expected to increase with climate change. The young, elderly, poor, and infirm are most vulnerable to heat waves, which can cause dehydration and heat stroke. Heat waves will also disproportionately affect those in urban areas (as cities are hotter than rural areas), and those in northern climates (as they are not accustomed to hot temperatures).

  2. Extreme Weather Increasing storm severity is also a projected consequence of climate change. Large storms can cause drowning and injury, disrupt municipal and medical services, and leave people displaced from their homes. As with heat waves, vulnerable populations will be affected most. Displacement can cause mental health issues, and reduce access to fresh food and water.

  3. Reduced Air Quality Heat waves produce stagnant air, which can lead to increased ground level ozone and increased levels of fine particulate matter. Ground level ozone is a harmful pollutant that can damage lung tissue and exacerbate existing lung conditions. Those with asthma and chronic lung disease are especially vulnerable. Fine particulate matter is a category of extremely small particles and liquid droplets suspended in the atmosphere which, when inhaled, can produce a variety of health problems including premature death, aggravation of cardiovascular and respiratory disease, development of chronic lung disease, exacerbation of asthma, and decreased lung function growth in children.

    The duration and severity of the spring pollen season may also be increased due to climate change, as well as the spread of ragweed, which is an invasive plant with very allergenic pollen.

  4. Climate-Sensitive Diseases Certain food-borne, water-borne, and animal-borne diseases may increase with climate change. For example, salmonella and other bacteria-related food poisoning incidences could increase because these bacteria thrive in warmer environments. Heavy rainfall and flooding may increase water-borne parasites such as Cryptosporidium and Giardia that are sometimes found in drinking water. Finally, warmer temperatures may increase the ranges of disease-carrying insects such as ticks that carry Lyme disease, and make the U.S. more hospitable to mosquitoes that are vectors for the West Nile virus.


1. Centers for Disease Control and Prevention, Climate and Health Program, www.cdc.gov/climateandhealth/effects/default.htm

2. Food and Agriculture Organization of the United Nations (2006), Livestock’s Long Shadow.

3.U.S. Environmental Protection Agency, Agriculture and Food Supply, www.epa.gov/climatechange/impacts-adaptation/agriculture.html