Physicians and the Environment

The medical profession has responded to adverse situations of global reach, such as epidemic diseases and natural disasters. As the world's scientists, governments, and businesses now confront the state of the environment, physicians also must be prepared to respond.

The environment is today's most pressing global issue. Environmental conditions contribute to the presence or intensity of many medical conditions, as with temperature-related morbidity and mortality, health effects of extreme weather events (eg, storms, floods, tornadoes, hurricanes, and precipitation extremes) and their sequelae (eg, oceanic algae blooms), ecological change (eg, the potency of certain harmful plants), starvation, allergies, pollution-related health effects, water- and food-borne diseases, and vector- and rodent-borne diseases.^{1 - 2}

Global climate change and other environmental issues are worthy of physicians' attention and understanding, although the full eventual effects on human health are not well defined. Some of the most important issues include global warming, depletion of stratospheric ozone, destruction of forests, polar melting, deficiencies in water production and sanitation, and human population growth and dynamics.

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^oC, some suggest that only a decade may be needed to raise it another 0.28^oC.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

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 UV-B radiation. This contributes to skin cancer, cataract formation, immune suppression, and damage to certain crops.⁹

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

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 2007, for the first time on record, the Northwest Passage briefly became navigable. 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

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 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

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 are 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 will 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. While there are a wide variety of opinions about the timeline for such events, the arguments supporting these 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.

Environmental remediation recommendations are topics of great debate. Because the nature and magnitude of environmental changes have only recently come to be recognized, it is difficult to predict the attribution of inevitable to natural cycles, or whether the forces of nature are becoming unbalanced. Some suggest that while human activities have an effect on climate, there is not proof that this affects global temperature. For instance, there may be years during which global temperature declines. Others acknowledge the inevitability of global climate change, but recommend adaptation or geoengineering solutions.²³ Opponents of those who predict irreversible global climate change and warming argue that until the precise nature and rate of these phenomena can be established, governments and industries should be tentative and cautious about making expensive policy decisions.²⁴ Still, others point out that by focusing attention on global warming, there is a risk of not properly addressing more important environmental and health issues.

Certain issues are beyond calculated inaction. Developing alternative sources to substitute for fossil fuel consumption is widely supported. Even though there is almost universal assent and agreement on many issues, politics, economics, and special interests delay progress. Significant behavioral changes are needed to begin to reverse apparent deleterious trends. Achieving global environmental change requires public and private efforts, led by a massive educational effort that should include all institutions of higher learning, including schools of medicine.

By virtue of their knowledge and experience, physicians are rightfully concerned about individual and population health. However, medicine's focus on pathogens and disease processes may be misguided compared with the potential loss of life that may result from such environmental eventualities as the melting of the polar caps. The time has come to consider broadening what the medical profession must learn, expanding awareness by educating physicians about the best environmental science. Given the hypothetical and known links of global climate change to human health, and the increasing concern that this change is accelerating, medicine must be involved in any proposed remediation.

Accordingly, in response to the environmental imperatives, an educational action plan is appropriate for the medical profession. Nelson²⁵ noted about environmental studies, “ . . . the subject matter is all-encompassing. It includes . . . the air, water, minerals, soil, forests, oceans, lakes and rivers, as well as all living things in the seas and on land, the relationship and influence of each on the others, plus economics, politics, religion, culture, and philosophy. And, although we will never know or understand more than a small fraction of the endless intricacies of nature's works, we can comprehend and learn the general principles that should guide our conduct as a society, if we are to preserve a livable habitat. The proposition is, quite simply, that we must conduct our activities in such a way as to protect the integrity of our ecosystems and their resources. . . . ”

There are several potential methods for physicians to increase awareness and involvement with environmental issues. First, an elective course on the relationship of environmental issues to human health should be offered as part of the medical school curriculum. To cover the principles of environmental science and related medical issues, this course should include information on atmosphere and climate; global climate change; the relationship of climate change and weather to disease vectors and transmission; the effect of climate change on the biology and afflictions of humans, plants, and animals; methods for assessing climate-related health effects; ecology and the environment; biodiversity and human health; natural environmental hazards; causes and effects of environmental contaminants; food and water science; and the causes and effects of population growth. The standardized course should be prepared and reviewed for accuracy and objectivity by authoritative environmental scientists and educators, in collaboration with medical professionals.

Second, medical societies, specialty organizations, and research institutes should assemble experts to summarize the best evidence about the effects of environmental change on health and medical conditions. This continuous process should foster exchange of views that takes into account medical, social, geopolitical, economic, and cultural issues. The opinions that emanate from the medical profession should be science-based to the greatest degree possible. Whenever new evidence emerges, current views may need to be modified as they relate to both the environment and medicine. In addition, medical organizations should consider reviewing their missions, and determine to what extent they are willing to disseminate environmental education material to their membership. Medical organizations should encourage members to become environmentally aware, and consider creating reports and multimedia presentations on global environmental health for delivery to medical professionals, students of medicine, business, government, and the general public.

Third, physicians should investigate environmental organizations and consider supporting them with their special medical expertise. When appropriate, physicians can develop specific initiatives in collaboration with environmental professionals. Moreover, physicians should learn about companies that truly use environmentally sound practices in their business efforts and consider supporting them.

Fourth, hospitals and health care practices should make reasonable efforts to become green in ways that promote effective patient care while limiting the negative effect on the environment of providing that care.

The educational goals are to be better informed, become inspired, and take action. In the countless debates that will ensue, physicians should be positioned to wisely explain the medical ramifications of environmental issues. Efforts by the International Society of Doctors for the Environment, the Climate and Health Council, Utah Physicians for a Healthy Environment, and the Canadian Association of Physicians for the Environment exemplify a beginning. It is time to eliminate complacency and acknowledge the common “planetary patient” of all physicians. Through education and personal resolve, every physician should strive to be a physician for the environment.