Overview of health consequences of climate change.
Image courtesy of World Health Organization.
The Health Consequences of Climate Change
By Catherine Cavanaugh, DO
This is the third-place winner of the 2008 Namey/ Burnett Writing Award, implemented by the ACOFP Preventive Medicine and Medical Preparedness Committee to honor the best preventive medicine papers submitted by osteopathic family practice residents, and medical students.
ABSTRACT: Evidence of global climate change is “unequivocal” as stated in the latest report from the Intergovernmental Panel on Climate Change. As average global surface temperatures increase, numerous threats to human well-being are mounting. While there is no panacea to solving the problem of climate change, appropriate primary prevention and mitigation strategies can lessen the impact on ecosystems, which are fundamentally necessary for human health. Ultimately, becoming cognizant of the lifestyle that has been adopted throughout the years and changing it to be more mindful of its ecological impact will benefit not just future generations, but also public health in the more immediate future.
“We travel together, passengers on a little spaceship, dependent on its vulnerable reserves of air and soil; all committed for our safety to its security and peace; preserved from annihilation only by the care, the work, and, I will say, the love we give our fragile craft.”1
-Adlai Stevenson
The climate is changing. It is driven by human action, the consequences are dire, the course must be altered, so buck up and change or else.
That may be how many people feel when contemplating this daunting issue, and it may be that many people feel compelled to ignore the dilemma, wrongly thinking it unalterable. True, the climate is warming. Health care practitioners ought to be concerned, for climate change brings with it numerous threats to human well-being including heat mortality, extreme weather events, disease outbreaks, poor air quality, and limited resources with associated political instability (see Figure 1). However, appropriate primary prevention and mitigation strategies can lessen the impact of climate change on human health and on ecosystems.
Introduction
“Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.”2
- Fourth Assessment Report, Intergovernmental Panel on Climate Change (IPCC)
Average global surface temperatures have increased at an approximate rate of 0.74ºC from 1906-2005, with the rate of warming over the last 50 years nearly twice that of the last 100.3 Carbon dioxide concentrations, one of the main causal elements of global warming, have been recorded annually at the Mauna Loa Observatory in Hawaii since 1958, when it was first documented at 315 ppm. Since the beginning of the Industrial Revolution carbon dioxide concentrations (as measured by arctic ice cores prior to 1958) have risen from around 280 ppm to 380 ppm (see Figure 2).4 In addition to higher surface temperatures the rise in carbon dioxide has resulted in elevated sea levels, a decrease in northern hemisphere snow cover, and accelerated rates of glacial melt (see Figure 3). If burning of fossil fuels is not significantly reduced, doubling of carbon dioxide emissions could occur sometime after 2050, which is predicted to yield a rise in global temperature of 1.7 – 4.4 ºC.5
Heat Mortality
The summer of 2003, which saw an estimated 22,000 to 35,000 lives lost in five European countries, was most likely the hottest summer since at least AD 1500.6 Heat waves are only expected to increase and the number of heat-related deaths estimated for a mid-century summer is projected to more than double.7
Those most affected will continue to include the young, old, and obese as they have a decreased capacity to regulate body temperature, those who are socially and geographically isolated, the mentally ill and immunocompromised, outdoor workers and those without air-conditioning, and people in poverty. The anticipated increase in the number of elderly and obese suggests, all else equal, that the U.S. population will become increasingly vulnerable to the health impacts of climate change.8
Mid-latitudes are more affected by heat mortality as there is a wider range of summertime temperatures and a milder climate. Acclimatization offers some protection from a sudden or prolonged increase in temperature for people who consistently live in warmer environments.7
Extreme Weather Events
Although climate change cannot be blamed for any one particular weather disaster, it is responsible for longer-term trends intensifying weather around the world. A fluctuating climate spawns more heat waves, droughts, intense downpours, and floods (See Figure 4). Moreover, there is a high likelihood that future tropical cyclones will become more intense, with greater peak wind speeds and heavier rains. Conclusions from the IPCC state that there is a greater than 90 percent likelihood that such weather events will continue to become more frequent.3
Mental and emotional distress associated with natural disasters is extremely common and includes posttraumatic stress disorder, sleep disturbance, aggressive behavior, depression, and substance use/abuse.6,9
Infectious diseases often surface in clusters in the wake of extreme weather events as sanitation, sewage treatment, and water-purification plants are damaged or overwhelmed, and people are crowded into temporary shelters. Outbreaks of infectious diarrhea, which globally is the second-leading cause of death in young children, is commonplace.9 In November 1998, Hurricane Mitch, nourished by a warmed Caribbean, dumped six feet of rain that killed more than 11,000 people. In the aftermath, Honduras reported 30,000 cases of cholera, 30,000 cases of malaria and 1,000 cases of dengue fever.6 Heavy downpours after periods of drought can be particularly harmful, causing sewer overflow and contaminated rain runoff from farms, lawns, and streets to enter drinking water supplies. This often correlates with outbreaks of waterborne diseases such as cryptosporidiosis, giardiasis, and cyclosporidiosis.5
Vectore-borne Illness
Vector-borne illnesses may increase when storms or floods create large amounts of standing water suitable for breeding. Perhaps most widely documented is the association between intense flooding and the explosion of mosquito populations, creating outbreaks of malaria, dengue fever, Ross River virus, and West Nile virus.5
In 2000, Mozambique experienced a devastating series of three tropical cyclones and heavy rains over a six-week period. Hundreds of people were killed directly and thousands more were displaced. The post-flood propagation of mosquitoes led to a malaria epidemic with some areas showing a four-to-five fold spike in malaria cases.6
In the 1999 outbreak of West Nile virus in New York City, 62 people developed encephalitis and meningoencephalitis of which seven died. Of the 55 survivors, many suffered prolonged or persistent neurological impairment.6
Worldwide, the range of mosquitoes is expanding to include higher altitudes and latitudes as propelled by climate change. Warmer temperatures amplify the life cycle of the mosquito and accelerate the development of the parasite within the host, while mild winters fail to kill mosquitoes.6,9 Drought and rain cycles, particularly in urban landscapes, increase the contact of mosquito vectors with birds and humans.
Flooding which occurs after drought also promotes rodent-borne disease outbreaks such as Hanta virus and plague as rodent populations swell in the wake of replenished water supplies.5
Air Quality
Allergic diseases are the sixth leading cause of chronic illness in the United States, affecting roughly 17 percent of
the population.6 Approximately 40 million Americans suffer from allergic rhinitis and the Centers for Disease Control (CDC) and Prevention estimate asthma prevalence in the United States at around 9 million children and 16 million adults.6
A combination of increasing allergen exposure and air pollution could be one factor behind an epidemic of allergic diseases being observed throughout the world. Controlled-environment experiments show that plants grown at two times ambient CO2 produce 40 to 61 percent more pollen than do controls.6,10
Higher ozone levels have been linked to mortality from heart and lung ailments, as well as the incidence of asthma attacks.5 Ground-level ozone is formed by the combination of nitrogen oxide and volatile organic compounds emitted from vehicle tailpipes, and warmer weather accelerates this creation.
High levels of particulate air pollution affect the growth of the lungs, and also increase rates of preterm births, low birth weight, and infant mortality.9 Particulates are mainly produced from coal-fired power plants, industrial boilers, diesel and gas-powered vehicles, and smelting operations. Many of these industrial processes are located in less affluent geographic areas and thus have a disproportionate effect on people living in urban areas.
Diminished Resources and
Political Instability
Diminished resource availability will conceivably cause large-scale migration driven by abrupt climate change, natural disaster, and political instability. Food availability could change dramatically with warming, altered weather patterns, decline in species diversity and changes in the abundance and distribution of pests.6 The United Nations Food and Agricultural Organization reports that there has been continual per capita decline in the production of cereal grains worldwide for the past 20 years, with grains accounting for 80 percent of the world’s food supply.6
Warmer sea surfaces, changing wind patterns and more evaporation from the ocean, alter precipitation patterns on land, bringing more moisture to some areas and diminishing it in others. Many semi-arid subtropical regions, already plagued by drought, could have as much as a 20 percent drop in rainfall by 2100.5 In other regions it is raining less often but harder, causing extensive floods.
The melting of mountain snow packs, enormous reservoirs of fresh water, has begun to affect water availability in the western United States and many other regions.5 If present consumption patterns continue, the United Nations Environment Programme estimates that two out of every three persons on Earth will live under water-stressed conditions by the year 2025, without taking into account a changing climate.6 Many of the world's arid and semi-arid regions cover developing countries, where water stress is compounded by poor infrastructure for collecting, disinfecting and delivering water.
Coastal populations, such as those in Shishmaref, Alaska, are being forced to move as a result of rising sea level and melting permafrost. As warming occurs, the ocean surface waters undergo thermal expansion, while land-based glaciers and ice sheets melt and discharge fresh water into the rising oceans.
The IPCC predicts global sea level to rise by 7 to 23 inches by 2100.3 Along low-lying areas such as coastal river deltas, a relative sea level rise of one foot would allow water to permanently submerge hundreds of feet of inland coast. Even a modest rise in relative sea level can create higher hurricane surges leading to more destructive flooding.
Solutions
Impacts are made continually to the environment that either compound or assuage the problem of climate change. There is no panacea, but by combining small and large efforts the scale may be tipped in a direction more favorable to the Earth and its constituents. The more effort put forth to aid the environment, in turn promotes the health and wellness of patients and communities.
Personal Interventions
Inside the home:
Reduce, reuse and recycle, in precisely that order. Reduce waste by buying grocery items in bulk or those in the least amount of packaging. Compost produce waste, as the oxygen required to break down organic waste is not present in landfills. For more information on composting go to: nyccompost.org.
Reuse containers, clothing and other items by downcycling. And finally, recycle. Some tips can be found at: coopamerica.org and earth911.org/.
Reduce junk mail which uses vast amounts of wood resources. For more information go to: catalogchoice.org/ and newdream.org/junkmail/.
Adjust thermostats a few degrees lower in winter and higher in summer and add appropriate insulation to the home, while layering clothing in winter.
Dry laundry on a clothesline or rack, extending the life of the clothes while reducing energy use.
When remodeling the home look into salvage yards and check out: recyclingthepast.com/ and getwithgreen.com/. Instead of sending usable items to landfill put them on freecycle, an online database for giving things away, found at: freecycle.org/, or have a yard sale. When purchasing new appliances and electronics look for the energy star label and recycle old items appropriately. To learn more about e-waste recycling check out “The Perils of E-waste at: coopamerica.org.
Don’t drink bottled water. Instead buy a reusable container and filter water if there are concerns. Examples of reusable containers can be found at: reusablebags.com. Consider rainwater harvesting particularly for garden and lawn use.
Outside the home:
Walk or bike to work or consider moving closer so this is an option. Another alternative is carpooling that saves money on gas and provides camaraderie. Also, consider
commuting in a more fuel efficient vehicle.
Use cloth shopping bags and produce bags found at: resusablebags.com.
In the community:
Support the local economy when possible, be it food products or handmade goods. Examples of local food sources can be found at: localharvest.org/,
sustainabletable.org/ and eatwild.com.
Establish a city council seat that represents “future generations”. Participate in public meetings as a patient advocate and write editorials and letters to representatives.11
Develop partnerships with other organizations to more effectively address the health aspects of climate change.
Clinic and Hospital Interventions:
Reduce paper waste with handy programs like this: printgreener.com and use recycled paper products.
Replace incandescent bulbs with LED and fluorescent lighting, and install motion sensors in low traffic areas.
Plug computers, lights and appliances into power strips which can then be switched off overnight.
Support “green energy” programs. More information can be found here: ucsusa.org.
Conduct an energy audit and then work toward Leadership in Energy and Environmental Design (LEED) certification.
Reward workers who carpool, use public transit, or power themselves to work.
Public Health Interventions:
Heat Mortality: Educate the public on the signs of heat stress and appropriate acclimatization strategies they can use such as increasing water intake, and seeking shade or air conditioning.12 Establish cooling centers with transportation for those who lack other options.
Extreme Weather Events: Provide technical advice in the development and implementation of preparedness and response plans for health threats such as heat waves, severe weather events, and infectious diseases.13 Identify population groups at risk for specific health threats. Provide point-of-use disinfection at any water source and scale up water sanitation. Push for legislation to protect and re-establish ecological buffer zones along coasts.
Vector-borne Illness: Track and report data to the CDC on environmental conditions, disease risks, and disease occurrence related to climate change.13 The CDC has more information at: cdc.gov/. Look to reduce sources of mosquito breeding sites, and implement the use of insecticide-impregnated bed nets in malaria endemic areas.6 To support net projects go to: nothingbutnets.net.
Air Quality: Support policies to expand parks, green spaces, community gardens, public transit, sidewalks and bicycle lanes. Bike lanes and sidewalks should be added to every road under reconstruction if not already present. To learn more about green spaces go to: actrees.org/site/ and ftpf.org/. Limit automobile idling which increases particulates and affects air quality.6
More information is found at: epa.gov/smartway/idling.htm. Support or establish urban gardens to replace abandoned city lots where ragweed and other allergen producing plants grow.6 Almost every major city has an urban garden program.
Conclusion
Climate change yields outcomes affecting every facet of life including the health and welfare of the human species. A true preventive strategy of addressing climate change needs to ensure the maintenance and development of healthy environments both locally and globally. Sustainable development and protection of ecosystems are fundamentally necessary for human health, not just for future generations, but also to benefit public health specifically in the more immediate future.14
If the majority of people were to change at a local level it would translate to transformation on a global scale. To begin requires becoming aware of the lifestyle that has been adopted throughout the years and changing it to be more mindful of its ecological impact. Indeed, this change of mind-set would be the single most powerful
benefit for this planet and its beauty for generations to come.
Dr. Cavanaugh is a 2008 graduate of Michigan State University College of Osteopathic Medicine. She will be pursuing a residency in family medicine and a master’s degree in public health environmental studies after an internship year with Henry Ford Health System. She would like to extend her thanks to Eric and all those who have given their love and support throughout the years.
| Figure 1. |
|
Overview of health consequences of climate change. |
| Figure 2. |
 |
Image courtesy of: http://www.mlo.noaa.gov/ |
References
Non-cited References
