How does this relate to public health?
Rising average temperatures and more frequent and more intense heat waves due to climate change are affecting human health in several ways. Most directly, warmer average temperatures and more extreme temperatures put more people at risk for heat-related death and disease, such as heat stroke and dehydration.1 For example, in North Carolina, the number of heat-related visits to the emergency department increases by 15.8 for every 1Â°F increase in temperature from 98Â°F to 100Â°F.2
Older adults and young children are vulnerable to heat-related illnesses. However, over the past two summers, North Carolina has seen the greatest number of heat-related visits to the emergency department among men ages 25-64.3,4 In addition, heat stress increases the risk for other diseases, especially respiratory death. In the U.S., severe heat events account for more deaths than all other extreme weather-related events combined each year. With increasing temperatures due to climate change, summertime heat-related deaths are expected to increase significantly, while wintertime deaths are expected to decrease slightly.1
Warmer temperatures also diminish air quality by increasing exposure levels of ground-level ozone. Ozone is a dangerous air pollutant that is damaging to lung tissue and lung function, and can exacerbate respiratory diseases such as asthma or chronic obstructive pulmonary disease (COPD).1,5
|Figure C: The International Panel on Climate Change (IPCC) demonstrates how a slight shift in average temperatures results in more frequent bouts of hotter weather.
|Image from www.ipcc-wg2.gov
Rising mean temperatures may also diminish water quality, which will in turn impact human health. Warmer temperatures may lead to the proliferation of pathogens and harmful bacteria in drinking water, recreational waters, and marine waters.5 Exposure to these pathogens can result in waterborne diseases. For example, consumption of food such as shellfish that is contaminated with Vibrio vulnificus, a naturally occurring estuarine bacterium, generally causes vomiting, diarrhea, abdominal pain, and death. Moreover, warmer temperatures have been associated with an increase in harmful algal blooms (HABs) along the coasts of the U.S. Certain HABs (especially cyanobacteria) are known to emit toxins that can cause neurological damage in humans.6
Figure D: Cyanobacteria, or bluegreen algae, are commonly found types of harmful algal blooms in North Carolina.
Image from NCDENR Division of Air Quality
Similarly, warmer average temperatures have led to milder winters and hotter summers, which in turn may impact the risk for vectorborne or zoonotic diseases. As temperatures rise, the geographical spread of diseases like Lyme disease or West Nile virus may change.1
1Portier CJ, et al. 2010. A human health perspective on climate change: a report outlining the research needs on the human health effects of climate change. Research Triangle Park, NC: Environmental Health Perspectives/National Institute of Environmental Health Sciences. doi:10.1289/ehp.1002272 <www.niehs.nih.gov/climatereport> Accessed November 17, 2012.
2Rhea, S; et al. 2012. Using near real-time morbidity data to identify heat-related illness prevention strategies in North Carolina. Journal of Community Health 37:495-500. DOI 10.1007/s10900-011-9469-0.
3North Carolina Division of Public Health, Occupational and Environmental Epidemiology. The 2011 North Carolina heat report. July 2011. <http://publichealth.nc.gov/chronicdiseaseandinjury/doc/HeatReport-13-2011.pdf> Accessed November 17, 2012.
4North Carolina Division of Public Health, Occupational and Environmental Epidemiology. The 2012 North Carolina heat report. July 2012. <http://publichealth.nc.gov/chronicdiseaseandinjury/doc/HeatReport20-2012.pdf> Accessed November 17, 2012.
5Environmental Protection Agency. Climate change: Human impacts and adaptation. June 14, 2012. <http://epa.gov/climatechange/impacts-adaptation/health.html#impactsreducedair> Accessed November 17, 2012.
6Centers for Disease Control and Prevention. Harmful algal blooms (HABs). July 24, 2012. <http://www.cdc.gov/nceh/hsb/hab/default.htm> Accessed November 17, 2012.