"Climate Change Harms Human Health"
by Lauren Simenauer, in a Science Progress cross-post
Delegates from 194 parties are meeting in Durban, South Africa, for the annual U.N. Conference of Parties, or COP, climate change conference. Among topics being addressed is the reduction of carbon emissions worldwide, clean energy funding in lower-income nations, and the future of the Kyoto Protocol. One lesser-discussed issue that diplomats will address is the growing body of science about the impacts of climate change on global health.
The National Resources Defense Council, or NRDC, identified six natural disaster events thought to be exacerbated by climate change. Those events include ozone air pollution, heat waves, the spread of infectious disease, river flooding, hurricanes, and wildfires. Tragically, extreme weather ravaged Durban itself just days before international delegates arrived. Torrential rains caused severe flooding that destroyed 700 homes and resulted in the deaths of 10 people. But beyond the immediate effects, all these disasters have wide-reaching consequences for national health, and a study published in Health Affairs magazine estimated that health costs incurred from the tragedies exceeded $14 billion from 2000 to 2009.
In the national debate on health care, it is imperative that the international community and our lawmakers at home not ignore the value of preventing the damage that climate change will cause to both the environment and human health.
The whole story
In a 2003 report, the World Health Organization, or WHO, posited that perhaps not all effects of climate change will be detrimental. Milder winters in temperate areas might mean a decrease in the death toll during the coldest months. Further, higher average temperatures in tropical areas could kill off mosquitos that carry deadly infectious diseases.
The WHO was careful to note that human vulnerability to climate change depends on population density, economic stability, food availability, income distribution, and various other mitigating factors. Thus, it is possible that not everyone will suffer uniformly. The WHO concluded, however, that on the whole, the ill effects of climate change will disproportionately affect lower-income regions and nations compared to post-industrial nations. The disadvantages to global health, the WHO concluded, will outweigh the few potential perks of climate change.
The immediate effects of climate change on human health are perhaps clearest. It is no secret that heat causes dehydration and that carbon emissions result in air pollution. The Centers for Disease Control, or CDC, noted that heat waves account for the highest proportion of weather-related deaths annually, with children and older adults most susceptible. The CDC estimated that heat-related deaths could climb from about 700 a year to between 3,000 and 5,000 by the year 2050, given expected levels of human-caused warming. In order to counteract the loss to human life, the CDC recommended air conditioning for poorly ventilated areas, though such utilities are hard to come by in the lower-income areas that need them most.
The Environmental Protection Agency, or EPA, reported that an increase in particulate matter will exacerbate respiratory diseases. While some air pollutants may occur naturally, as in the case of volcanic ash and dust, there is reason to believe that a significant portion of particulate matter in the air is anthropogenic—that is, humans produce them by burning fossil fuels. NASA estimates that humans cause at least 10 percent of aerosols, a particularly hazardous type of air pollution that contributes to the greenhouse gas effect and the deterioration of human health. An increase in ground-level ozone is also associated with decreased lung function, as well as cancer.
The CDC elaborated on potential detriments to asthma and airway diseases; fine particles in the air are associated with heart attack and blood clots. Indirectly, early flower blooming increases pollen, which can cause allergic reaction. Higher temperatures also increase mold spores, further irritating respiratory diseases. Furthermore, more frequent droughts may lead to increase in airborne dust, and increasingly frequent wildfires caused by climate change may also contribute to particulate matter.
A January 2010 report from the EPA offered a conservative estimate that heat waves cost the public $5.1 billion a year in health costs. The EPA put the baseline cost for asthma and respiratory illness at $5 billion. Additionally, the EPA estimated that public health costs incurred by poor indoor air quality and communicable respiratory diseases could exceed $10 billion.
With climate change comes extreme weather: more frequent and severe flooding, storms, and forest fires. The 2007 report of the Intergovernmental Panel on Climate Change, or IPCC, found that the number of hurricanes had increased annually since 1970, writing, “There is observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970, correlated with increases of tropical sea surface temperatures.”
The IPCC went on to predict an influx of hurricanes in the near future:
Based on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs. There is less confidence in projections of a global decrease in numbers of tropical cyclones. The apparent increase in the proportion of very intense storms since 1970 in some regions is much larger than simulated by current models for that period.
The cost to human life from extreme weather is significant. Scientists and economists from the NRDC estimated that Florida hurricane season racked up $1.4 billion in health bills in 2004 alone. California wildfires cost $578 million in 2003, and flooding in North Dakota cost $20 million in 2009. Many of these figures do not take into account the added cost of damage to hospitals and other health care infrastructure, as well as the costly effects to health that pervade the population years later in the form of heart disease, cancer, and disorders of mental health.
Implications for disease control
As the globe heats up, the outlook for the containment of pathogens is becoming increasingly dismal. Rising average temperatures worldwide expand the range and seasonality of communicable diseases unique to warmer months. The WHO estimated that climate change was responsible for 2.4 percent of deaths from diarrhea and 6 percent of deaths from malaria in middle-income countries in the year 2000.
The Commission on Climate Change and Development, or CCCD, emphasized the importance of containing the rise of vector-borne diseases. Though the WHO does not predict that climate change will incite the mutation of new diseases, climate change could precipitate the resurgence of diseases that have plagued human history. Aside from malaria and diarrheal diseases, the CCCD warned of an influx of cholera, which is linked to low river flows in the dry season, and possibly due to pathogen infection of standing pools of water that result. Also of concern is an increase in rodent-borne diseases after flooding, and meningitis is linked to drought and heat, though the mechanism for transmission is still unclear.
Dengue fever and a spike in food-borne illnesses could also result from continued climate change, according to the same WHO study. A report from the National Institutes of Health, or NIH, suggested that an increase in temperatures will result in more contamination of crops. The NIH also reported that drought increases the prevalence of insects and other pests that can hamper agricultural productivity.
Of particular concern is the seafood supply. The CDC warned that algal blooms are known to release harmful neurotoxins that cause death in humans; marine organisms can also pick up these neurotoxins. The most common neurotoxin that blue-green algae releases is anatoxin-a, which interrupts neurotransmitter activity at neuromuscular junctions and can cause muscle paralysis and even death from respiratory failure. Because cooking seafood does not necessarily kill harmful biotoxins, these harmful chemicals pose a unique threat to the food supply. Measures to prevent contamination of the food supply may not be consequential, however, as the CDC reports that it is also possible that marine neurotoxins will be aerosolized by the surf crashing onto the beach and dispersing into the wind.
Communicable diseases are only the tip of the iceberg when it comes to health impacts of climate change, according to the CDC. With increases in temperatures comes an increase in the volatility of certain dangerous chemicals associated with cancer. Such hazardous chemicals like ground ozone, black carbon, diesel exhaust, and ammonia, are also known to be dispersed with heavy rainfall, which is associated with climate change. Further, the depletion of ozone means that more harmful UV radiation penetrates the atmosphere, increasing the occurrences of skin cancer.
The ripple effect
The direct consequences of climate change on public health are not relegated to the immediate effects of hotter averages and more extreme weather. The direct effects of extreme weather, like injury, property damage, and loss of life also create ripple effects that cause additional damage to society and public health. For example, the CDC warns that diminished access to food and water caused by drought could cause migration from rural to urban areas or vice versa. Migration itself is linked to health problems that impose a steep price tag for public funds. The International Organization for Migration reported that, among other health concerns, migration increases physical trauma and spreads diseases.
Additionally, climate-enhanced food insecurity has its own ramifications for human development. Starvation leads to malnutrition in mothers and, consequently, stunted development in fetuses and children.
Coastal flooding and pollution could impair food manufacturing and health care facilities. Reactions will vary regionally, but the consequences of population displacement, as well as the erosion of food manufacturing industries, may not be apparent for several decades.
Climate change is no longer just a looming threat in the abstract. Climate change is a hidden culprit with real impacts on health care costs, and, more gravely, human lives. Finding solutions to the climate crisis is no longer just an environmental issue. The effects of climate change permeate through all facets of human life, and preparing for the impact on health care should be a priority.
Lauren Simenauer is an intern with Science Progress and a senior at the University of Virginia. This piece was originally published at ScienceProgress.org.