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Global Warming

Global Warming

Rep. Edward J. Markey, Chairman - Stay Connected with Facebook, Twitter, YouTube and RSS Feeds
The Select Committee on Energy Independence and Global Warming addressed our nation's energy, economic and national security challenges during the 110th and 111th Congresses.

This is an archived version of the committee's website, where the public, students and the media can continue to access and learn from our work.


Climate change poses a serious threat to human health. The World Health Organization estimates that since 2000 one million people have been killed directly or indirectly because of our warming planet.  This is not including death from air pollution, which kills 800,000 people each year and is expected to worsen with global warming.  While we must learn to adapt to the health impacts of global warming, the only preventative medicine we have is to reduce our greenhouse gas emissions and stop future climate change. 

Dr. Pachauri speaks on global warming impacts on human health

Climate Change will impact human health in 5 main ways:

•    E coli, and other Water and Food Borne Diseases
•    Air Pollution
•    Rodents, Insect and Tick Borne Disease
•    Temperature Extremes  
•    Hurricanes, Storms and Severe Weather Disasters

E. coli, and other Water and Food Borne Disease

Water and food borne diseases are a problem for human health:
  • According to the CDC, food borne diseases are responsible for about 76 million cases of illness, with 325,000 hospitalizations and 5,000 deaths in the U.S. every year. Water borne diseases are responsible for about 9 million cases of illness every year in the US.  
  • The following diseases can all be transmitted by water and food contamination: E. coli, typhoid, hepatitis A, dysentery, cryptosporidiosis, polio, giardia, cholera and botulism.
  • Water treatment facilities have difficulty removing many water borne diseases from drinking water, including cryptosporidiosis and giardia.  Contaminated drinking water caused a cryptosporidiosis outbreak where 403,000 people became ill in Madison, Wisconsin in 1993.  A CDC report estimated the outbreak cost $96.2 million: $31.7 million in medical costs and $64.6 million in productivity losses.
  • Diarrhea, caused mainly by food and water borne diseases, is the second leading cause of death in young children.  According to the CDC each year and estimated 4 billion cases of diarrhea cause 2 million deaths.
How climate change can increase water and food borne diseases:
  • Increase in temperature causes more occurrence/survival of bacteria, toxic algae, and other contamination in food and water.  Also, according to the IPCC climate change is already reducing the amount of high quality freshwater and this situation is expected to worsen.  People will be forced to use poorer quality water sources, leading to increased disease.
  • The major pathogens that cause acute gastroenteritis multiply faster in warmer conditions.  According to a study on climate change impacts on the U.S., this is predicted to impact lakes and increase the number of recreational water borne disease outbreaks.
  • Climate change is predicted to cause more extreme flooding and storms, which are known to lead to contaminated water supplies. Heavy rainfall can cause sewer/ storm water systems to overflow, releasing raw (untreated) sewerage in local water sources.  
  • The WHO reported that in 2000 climate change was responsible for approximately 2.4% of worldwide diarrhea.  In 2030, warmer temperatures and more severe rainfall and flooding will cause up to a 10% higher risk of diarrhea in some areas.
  • According to the IPCC, the distribution and activity of flies, cockroaches, and rodents could change in response to climatic changes. These species are carriers of food-borne pathogens and are considered to be major hygienic pests in the domestic environment.

Air Pollution

Air pollution is a problem for human health:
  • Air pollution is known to cause asthma, worsen allergies, contribute to lung cancer, and lead to other lung and breathing related problems.  These health problems are on the rise in the United States, and scientists believe air pollution is a major contributor.
  • According to the EPA, asthma leads to 2 million emergency room visits and 5,000 deaths per year in the U.S. Asthma accounted for more than 14 million missed school days in 2000.  Finally, asthma costs (health care costs and lost productivity) totaled $14 billion in 2002. Asthma afflicts 20 million Americans, including 6.3 million children.
  • The prevalence of asthma increased 75% from 1980 to 1994 in both adults and children, but the biggest growth is asthma cases has been in children under 5.
  • Allergic diseases affect 17% of the United States population and are the sixth leading cause of chronic disease.  Approximately 40 million Americans suffer from allergic rhinitis (hay fever) primarily due to aeroallergens.
  • Air pollution contributes to COPD (Chronic Obstructive Pulmonary Disease).  COPD is a group of diseases that cause airflow blockage and breathing-related problems.  According to the CDC, COPD is a leading cause of death, illness, and disability in the United States. In 2000, 119,000 deaths, 726,000 hospitalizations, and 1.5 million hospital emergency department visits were caused by COPD. An additional 8 million cases of hospital outpatient treatment were linked to COPD in 2000.
How air pollution affects human health:
  • Ground level ozone (photochemical smog) can damage lung tissue, reduce lung function, sensitize lungs to other irritants and exacerbate respiratory disease.
  • Particulate matter can exacerbate respiratory and cardiovascular disease, lower the body’s ability to fight disease, damage lung tissue, contribute to cancer and lead to premature death.
  • Exposure to carbon monoxide, sulfur dioxide, and nitrogen dioxide can exacerbate respiratory and cardiovascular disease and damage the lungs.
  • Increased pollen can exacerbate asthma and increase the occurrence and severity of asthma. Increased pollen can also extend the duration or timing of seasonal allergies.
  • Molds cause or worsen certain illnesses (e.g., some allergic and occupation-related diseases and infections in health care settings).

How climate change has the potential to increase air pollution:
  • The IPCC reports that higher temperatures are associated with higher concentrations of air pollutants and reduced air quality, exacerbating health problems.
  • Increased temperature from global warming over the past several decades have caused many plants to start spring budding earlier in the year, increasing the amount of pollen allergens in the air.  Increased CO2 also causes some symbiotic fungi to grow faster and produce more spores.  Scientists believe this is contributing to the increase in people with allergies in the United States.
  • As temperatures rise, people will use more air-conditioning which without any change will lead to more energy use and increase air pollution emissions from power plants.
  • Ground level ozone is created by reactions from several tailpipe emissions (nitrogen oxides and volatile organic compounds).  These chemical reactions occur at a faster rater in higher temperatures.
  • Climate change is linked to an increase in forest fires which release large amounts of particulate matter and carbon into the air and reduces air quality.
  • Climate change can increase droughts which in turn increase the amount of dust in the air. Dust clouds carrying particles and microbes can be carried by wind and travel long distances. In 2001 NASA satellites tracked a dust cloud all the way from China across the pacific to Alaska and Florida.  It rained dust and pollution along the way.

Rodent, Insect, and Tick Borne Diseases

Rodent, insect, and tick- borne diseases are a problem for human health:
  • The WHO estimates that 1-3 million people die from malaria every year.  It is the most deadly vector borne disease known in terms of morbidity, mortality and lost productivity.  Approximately 75% of all malaria cases occur in children, and approximately 3,000 children die from malaria each day. 40% of the world is at risk for contracting malaria.
  • The CDC has tracked West Nile virus to almost all of the continental United States.  The cost of West Nile-related health care in 2002 was estimated at $200 million. In 2006 there were a total of 4,261 reported cases and 174 deaths in the United States.
  • Lyme disease has spread since the CDC began following the disease in 1991.  In 2006 almost 20,000 people became infected.
How climate change could impact rodent, insect, and tick- borne diseases:
  • Warmer temperatures mean many parasites, including malaria, develop more rapidly into adults, and have boosted biting and reproduction rates.
  • The WHO reported that in 2000, climate change was estimated to be responsible for approximately 6% of malaria in some middle-income countries.
  • The WHO concluded that the first detectable changes in human health may be alterations in the geographic range and seasonality of certain vector borne diseases.
  • There has been a global increase in highland malaria. Scientists at the Harvard Center for Health and the Global Environment believe a warmer climate has made higher altitudes more hospitable towards infectious diseases, increasing the risk they will spread.
  • Warmer and shorter winters allow more of the disease carrying rodent, insect, and tick populations to survive the winters and emerge with greater numbers in the spring and summer.
  • IPCC scientists have concluded climate change will likely increase extreme weather events, including floods. Extreme rainfall has been associated with growth of the disease carrying rodent population.

Temperature Extremes

Temperature extremes are a problem for human health:
  • According to the CDC, from 1979-2003, excessive heat exposure caused 8,015 deaths in the United States. During this period, more people in this country died from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined.
  • Exposure to extreme and prolonged heat is associated with heat cramps, heat syncope, heat exhaustion, heat stroke and death.
  • Heat related health effects seem to be related to temperatures above what the population is used to.  The most sensitive populations are those in which extremely high temperatures occur infrequently or irregularly.
  • Children, low-income, elderly, disabled and populations without air-conditioning are at high risk for heat-related illness.  Children and people who engage in sports or other strenuous physical activity outdoors are more susceptible to extreme heat.
  • Almost 500 people died in Chicago during a 1995 heat wave.  35,000 people are estimated to have died in Europe in a 2003 heat wave.

How climate change has the potential to increase temperature extremes:
  • As the average global temperature rises, heat and heat waves are expected to increase in severity and frequency, and predictions by the IPCC, USGCRP and WHO all point to an increase in heat related deaths.
  • WHO has predicted that climate change is expected to increase the annual summer-time deaths several-fold. For example, by 2050, an additional 500-1000 people in New York are expected to die, and 100-250 additional people in Detroit are expected to die because of climate change. (These numbers assume acclimatization. Without it projected numbers would be higher).

Hurricanes, Storms and Other Extreme Weather Events

How storms and extreme weather events affect human health:
  • Storms and other extreme weather events (such as tornadoes, hurricanes, floods, heavy rainfall) can cause direct harm through injury or death.
  • Storms can cause secondary health effects due to increased bacterial, mold and fungal counts and disruptions in food supplies or clean water.
  • According to the National Weather Service, extreme weather events caused 566 deaths and 3,489 reported injuries in 2006.
  • Survivors of severe natural disasters sometimes suffer from post traumatic stress disorder and other mental health problems. The CDC reported as many as 40% of Katrina victims suffered from PTSD.  A longitudinal study of residents who survived Hurricane Andrew should that 20-30% of adults in the area met the criteria for PTSD at 6 months and 2 years after the hurricane.  
  • Higher rainfall is linked to cryptosporidiosis and giardia contamination in river water and human disease outbreaks. Water treatment facilities have difficulty removing these parasites from drinking water.
How climate change can impact storms and extreme weather events:
  • The IPCC has reported that climate change is expected to increase the number of extreme weather events around the world, including North America.
  • Climate change is impacting the timing, location and amount of rainfall causing an increase in severe droughts and severe floods.  Over the last century in the United States heavy rains (2 inches of precipitation/day) have increased 14% and very heavy rains (over 4 inches/day) have increased by 20%.  
  • The IPCC report suggests the increased destructive power and frequency of large and powerful tropical storms is correlated with increases in ocean temperature caused by global warming.
  • The destructive power (a function of storm duration and peak winds) of tropical cyclones has more than doubled since the 1970’s.  
  • The number of global natural disasters is on the rise.  Munich Re, a reinsurance company, found that the number of disasters due to natural events have tripled over the past ten years as compared to the 1960’s.
  • Communities that have not experienced extreme weather events in the past are generally not prepared and impacts on human health are generally more severe in these areas.


Organizations addressing climate change impacts on human health:

•    Intergovernmental Panel of Climate Change
•    World Health Organization  
•    U.S. Global Change Research Program  
•    American Academy of Pediatrics
•    American Public Health Association
•    United Nations Development Programme


Reports on Climate Change and Public Health:

  1.  “Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change.” U.S. Global Change Research Program. 2001. p447.
  2. Climate Change and Human Health—Risks and Responses, Summary. WHO. 2003. p14 Accessed January 22, 2007
  3. “Climate Change Futures: Health, Ecological and Economic Dimensions” The Center for Health and the Global Environment Harvard Medical School. Nov 2005. p34. Accessed January 22, 2007.


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