Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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Outdoor Medicine and the Environment

I was recently fortunate to have a commentary entitled "Physicians and the Environment" published in the Journal of the American Medical Association. It was an invited piece, and reflected some of my thoughts about current environmental issues and the role of the medical profession in achieving the education necessary to be able to intelligently respond to these issues. I am going to use parts of that commentary to put this into context for the layperson, and am therefore including the references where appropriate from the original commentary.

As I have mentioned previously, there is every reason for persons involved and interested in wilderness and outdoor medicine to be advocates for preservation of the environment. The entire concept of "wilderness medicine" is predicated upon the existence and improvement of wilderness areas, which are among the most pressured and rapidly receding parts of planet Earth.

In many circumstances in the past, the medical profession has responded to adverse situations of global reach, such as epidemic diseases, genocide, the threat of nuclear war and natural disasters. As the world’s scientists, governments, and businesses now confront the state of the environment, all manner of health care professionals also must be prepared to respond, because in the final analysis, health matters are integral to the predicament, predictions and discussion. Beyond being just a reliable resource, given the magnitude and complexity of issues as they relate to human health, the medical profession should accept the challenge of becoming a leader in the discussions and debates.

Despite our preoccupation with armed conflicts and the economy, the environment is perhaps today’s most pressing global issue, as it contributes not only to direct effects, but to other situations of concern, such as economic decline and civil disobedience. Environmental conditions contribute to the presence or intensity of many medical conditions, such as temperature-related morbidity and mortality, health effects of extreme weather events (e.g., storms, floods, tornadoes, hurricanes, and precipitation extremes) and their sequelae (e.g., oceanic algae blooms), ecological change (e.g., the potency of certain harmful plants, such as poison oak), starvation, allergies, pollution-related health effects, water- and food-borne diseases, and vector- and rodent-borne diseases.1,2

As we learn more, it becomes apparent that the full eventual effects of global climate change and other environmental issues are not necessarily easily defined or well predicted. There are multiple views surrounding every issue. Some of the most important issues that need to be continuously examined from every angle include global warming, depletion of stratospheric ozone and increases in ground-level ozone, destruction of forests, polar melting, deficiencies in water production and sanitation, and human population growth and dynamics.

There are and will be significant differences of opinions about what follows here. My comments are properly interpreted as being "pro-environment" or "green," leaning toward the perspective that advocates that there are significant environmental problems and that many of these can be attributed to the activities of humans. However, I most certainly acknowledge the rights and responsibilities of others to hold different viewpoints and opinions, and the value of their being skeptical about science and conclusions. The most important thing is that we do not become acrimonious or disengaged, because it will take all of our skills of observation, analysis, and collaboration to reach consensus on these matters in a timely fashion and in a way that promotes improvement, not conflict. The acts of remediation are expensive and potentially diverting (from other problems), so no significant change should be taken lightly.

Global Warming.
Atmospheric accumulation of gases (predominately carbon dioxide, methane, nitrous oxide, and halocarbons) traps heat by the greenhouse effect.3 The Intergovernmental Panel on Climate Change predicted that average global temperature will continue to increase, and a major concern is the rate of warming.4 Compared with the century 1906-2005 required to raise the earth’s average atmospheric temperature by 0.56 degrees Centigrade, some suggest that only a decade may be needed to raise it another 0.28 degrees C.5 This rate of change has been created by burning fossil fuels in power plants and for transportation, a decline in carbon intensity reductions, and natural sinks removing a smaller proportion of emissions from the air.6 Each year, more than 1.2 cubic miles of oil, 3.5 billion metric tons of coal, and 100 trillion cubic feet of natural gas are burned worldwide, releasing 30 billion tons of carbon dioxide into the atmosphere.7 Without efforts to stabilize or decrease consumption of fossil fuels, the 14.9 billion metric tons of carbon emissions released by the United States, the European Union, China, and India in 2005 are projected to increase to 25.6 billion metric tons in 2030.8 Even if one disputes the precise numbers, we seem to be on an unsustainable spree of consumption. Is global warming due to rising carbon dioxide levels, and are these rising levels attributable to the activities of humans, or are these environmental "facts" part of a series of coincidences? We need to know the answer. How many barrels of oil, tons of coal, and cubic feet of natural gas can be extracted from the earth before we run out? At our current rates of consumption, when will this occur? We need to know the answers.

Depletion of Stratospheric Ozone. Chlorofluorocarbons and other ozone-depleting substances released into the atmosphere are major contributors to the destruction of ozone in the stratosphere. Depletion of the ozone layer exposes the earth’s inhabitants to increased amounts of harmful ultraviolet-B radiation. This contributes to skin cancer, cataract formation, suppression of the immune system, and damage to certain crops.9 This is counter-posed by accumulation of ozone at ground level, which contributes to lung disease and other health risks.

Destruction of Forests.
Fires set to clear forests for agriculture and grazing release carbon dioxide, which is a contributing factor to global warming. According to the World Bank, approximately 22 million acres of rain forests are destroyed by intentional fires each year, accounting for approximately 20% of worldwide carbon dioxide emissions.10 Wildfires, often coinciding with droughts, generate additional atmospheric carbon dioxide.11 In preindustrial times, the atmospheric abundance of carbon dioxide was relatively constant at 280 ppm; in the 1950s, the level was 300 ppm; in 2006, it had attained 381 ppm; and in 2008 it is increasing.12 At what rate are these forests being re-planted? Can men and women continue to remove habitat, plants, animals, and minerals from planet Earth at current rates and be assured that this does not pose a catastrophic future for our populations of life forms? We need to know the answers.

Polar Melting.
Consistent with the increase of global temperature, there is a loss of snow cover in the Northern Hemisphere, the amount of Arctic and Antarctic sea ice is diminishing, and glaciers are melting.13 Predictions suggest that in the next few centuries, sea levels could rise by as much as 17.8 cm to 6 m, and the Gulf Stream may be diminished or even eliminated.14 In low-lying coastal areas where populations cannot be protected by natural or artificial barriers, large numbers of climate refugees may be forced to migrate to other locations, thereby increasing population crowding. Global climate change also is predicted to contribute to flooding and fire risk; increase the intensity of cyclones (hurricanes) and heat waves; accelerate beach erosion and desertification; hasten species extinction; and diminish water and food (livestock, fish, and plants) availability.15 I have heard many arguments about animals, such as polar bears, that putatively face extinction because of hunting, habitat and climate change, loss of food supply, etc. Are important animal populations declining? Can or should we intervene in the decline of any species? What does history tell us about the effects of rising and falling sea level? We need to know the answers to these questions.

Deficiencies in Water Production and Sanitation.
Sachs16 contends that global climate change will tighten the availability of water, and force migration of hundreds of millions of individuals over the course of a few decades. According to the United Nations, more than 5 billion persons on Earth may live under severe water stress by the year 2025.17 Currently, 1.1 billion persons lack adequate water worldwide, 2.6 billion lack adequate sanitation, and 1.8 million children die each year because of one or both of these deficiencies.18 The outdoors can be beautiful, marvelous, and a tonic for the body and spirit, but it can also be a cruel, terrifying environment of forced survival. What is the true status of our water supplies, nation by nation, region by region? We need to know.

Human Population Growth and Dynamics. The human population is increasing exponentially, which has an unprecedented global effect on ecology and biodiversity. This effect takes place through overharvesting, introduction of nonnative species, pollution, and habitat fragmentation and destruction.19 As large, developing countries face increasing energy demands, they will undoubtedly burn increasing amounts of fossil fuels. The environmental conditions and climate changes that have been touted as major influences on health may potentially involve millions of individuals being injured or killed by floods, tsunamis, and cyclones; tens of millions afflicted by poorly controlled diseases that might emerge as a consequence of unchecked vectors (such as mosquitoes); hundreds of millions malnourished due to desertification, loss of crops, and insufficient potable drinking water; and ultimately, poor health and the loss of prosperity as individuals are crowded into a reduced landmass that may be too small to reasonably support their survival.20,21 The worldwide growth of the human population dramatically increases the possibility of loss of life-sustaining resource bases during large geological and weather events in a manner that limits human survival. Simply put, the more pins standing behind the lead pin when the bowling ball strikes, the more that are vulnerable to being struck down and swept away. We need to be very thoughtful about this, because hunger and economic deprivation inevitably lead to conflict and even war. So, basic human needs may trump our desire to divert crops, such as corn, to alternative fuels. We are already witnessing these effects.

While there are a wide variety of opinions about the timeline for such events, the arguments supporting environmental trends are substantiated by reasonable scientific observations.2,22 Proponents of accelerating global climate change suggest that given the rapidity of changes and their unforeseen consequences, successful adaptation would appear unlikely and unattainable. The most viable solution is to halt the inexorable assault on the environment as quickly and effectively as possible. Arguments that do not support these trends are espoused by dispassionate and intelligent individuals, who also care very much about their planet, but do not necessarily agree with the scientific conclusions indicating human-generated planetary degradation and climate change. Which faction is correct? Issue by issue, point by point, we need to know. What might be at stake are the futures of species and resources that cannot be easily regenerated, if they can be regenerated at all. On the other hand, if there are better approaches than those currently favored by environmentalists, then let them be identified and implemented.

image courtesy of National Museum of Australia Canberra

1. Patz JA, McGeehin MA, Bernard SM, et al. The potential health impacts of climate variability and change for the United States: executive summary of the report of the health sector of the US national assessment. Environ Health Perspect. 2000;108(4):367-376.
2. Confalonieri U, Menne B, Akhtar KL, et al. Human health. In: Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE, eds. Climate Change 2007: Impacts, Adaptation, and Vulnerability: Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, England: Cambridge University Press; 2007:391-431.
3. Collins W, Colman R, Haywood J, Manning MR, Mote P. The physical science behind climate change. Sci Am. 2007;297(2):64-73.
4. Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE, eds. Climate Change 2007: Impacts, Adaptation and Vulnerability: Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel of Climate Change. Cambridge, England: Cambridge University Press; 2007.
5. Solomon SD, Qin M, Manning Z, et al. Climate Change 2007: The Physical Science Basis: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, England: Cambridge University Press; 2007.
6. Canadell JG, Le Que´ re´ C, Raupach MR, et al. Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks. Proc Natl Acad Sci U S A. 2007;104(47):18866-18870.
7. Project Genie. Web site. Accessed December 1, 2007.
8. International Energy Agency. Web site. Accessed November 29, 2007.
9. Longstreth J, de Gruijl FR, Kripke ML, et al. Health risks. In: Environmental Effects of Ozone Depletion: 1998 Assessment. Nairobi, Kenya: United Nations Environment Programme; 1998.
10. World Bank Group. Pilot program to conserve the Brazilian rain forest. http: // Accessed December 9, 2007.
11. Wiedinmyer C, Neff JC. Estimates of CO2 from fires in the United States: implications for carbon management. Carbon Balance Manage. 2007;2:10.
12. National Oceanic and Atmospheric Administration, Earth System Research Laboratory, Global Monitoring Division. Trends in atmospheric carbon dioxide. http: // Accessed January 15, 2008.
13. Nicklen P. Vanishing sea ice. Natl Geogr Mag. 2007;211(6):32-55.
14. BBC Weather Centre. Climate change. /gulf_stream.shtml. Accessed December 10, 2007.
15. Trenberth KE. Warmer oceans, stronger hurricanes. Sci Am. 2007;297(5):45-51.
16. Sachs JD. Climate change refugees. chanID=sa006&articleID=E82F5561-E7F2-99DF-36D3CB7EB5DA209C&ref=rss. Accessed January 12, 2008.
17. United Nations Water for Life. Fact sheet on water and sanitation. http://www Accessed December 8, 2007.
18. World Water Council. Water crisis. Accessed January 20, 2008.
19. Biodiversity & Human Health Web site. The effect of human population on biodiversity. Accessed December 9, 2007.
20. Kerr RA. Global warming is changing the world. Science. 2007;316(5822):188-190.
21. Campbell-Lendrum D, Corvalan C, Neira M. Global climate change: implications for international public health policy. Bull World Health Organ. 2007;85(3):235-237.
22. Meehl GA, Washington WM, Collins WD, et al. How much more global warming and sea level rise? Science. 2005;307(5716):1769-1771.

Preview the 25th Anniversary & Annual Meeting of the Wilderness Medical Society, which will be held in Snowmass, Colorado July 25-30, 2008.

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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.