Amid the controversial problem of global warming and its potential impact on human health, there is a rush to fix the blame-either on human activities or natural weather cycles. But the issue is too important for that. We must develop rational strategies to fix the problem rather than fixing the blame.

Over  600 international scientists conclude that human activities that create carbon dioxide, methane, nitrous oxides and chlorofluorocarbons-known as greenhouse gasses-are likely to cause an atypical increase in Earth’s temperature, which, in turn, creates a sequence of ecological changes that are harmful to human health and wellbeing.

A scientific study by the United Nations’ Intergovernmental Panel on Climate Change (IPCC) noted that the Earth’s average surface temperature has increased beyond normal range since1861.

While the exact impact of global warming is uncertain, scientists agree that it will vary according to the severity of the environmental changes it causes and the vulnerability of a certain populations, based on age, nutritional status, health standards, economic development and their use of technology.

As global warming causes air temperatures to rise, it also brings changes in precipitation, increased saturation of moisture by the soil, melting of ice caps and a rise in sea level. Concurrent heat waves, changes in air and water quality, droughts, storms and floods with their resulting displacement of populations, raise the potential for adverse effects on public health.

Health Effects

While the health effects of global warming would vary by region, scientists predict that there will be a net increase in human fatalities.

The health consequences of rising temperatures were well documented during the heat wave that affected Europe, particularly France, in August, 2003, causing the estimated death of 30,000 people. In North America, the heat wave that affected Chicago in 1995 resulted in approximately 500 deaths.

The elderly who suffer from reduced capacity of thermoregulation, persons with pre-existing cardiovascular diseases, individuals serving in heat stressed occupations and those living in congested urban areas are more vulnerable to extreme heat waves than others.

Higher temperatures mean more secondary air pollutants released into the air, which harms human respiratory and cardiovascular systems.

The acute air pollution episodes that happened in London, England in 1952 claimed the lives of 4000 to 8000 people. In the United States, Donora, Pennsylvania was also subject to a disastrous wave of air pollution in 1948 when industrial effluent trapped in an inversion layer killed 68 people and damaged the hearts and lungs of hundreds more.

Global warming may affect the status of marine ecology by stimulating the growth of algae that produce toxins that can be transmitted to humans through the consumption of shellfish.

The increase in sea level caused by melting ice caps could lead to intrusion of seawater into fresh water supplies available to humans, plants and animals and exacerbate flooding brought about by increased precipitation.

Floods triggered by global warming induced climate change could have devastating health effects. The 1993 Mississippi River Flood displaced over 50,000 people, which increased their exposure to additional injury and disease.  The US National Center for Disease Control and Prevention noted an increase in mosquito and rat reports in Iowa as a result of that flood.

Flooding increases agricultural and urban runoff, which can lead to greater human exposure to toxic chemicals. Floods also interfere with delivery of medical and other public safety services. The catastrophic flooding and health problems caused by Hurricane Katrina illustrated this fact.

The spread of diseases is another reason to be concerned about global warming. Seasonal patterns of communicable diseases may change, and the humid habitat in which mosquitoes flourish may increase. Populations of people that were once relatively unaffected by those problems would be at greater risk of becoming seriously ill.

According to one simulation model, climate change from global warming may add millions of cases of malaria per year in certain parts of the world. There are indications that a severe influenza-like disease known as Dengue has spread to higher elevations in Mexico, areas that have not previously reported Dengue cases. American health officials are concerned about the implication of that change on people living in southern regions of the United States.

There are predictions that climate change will affect food production in certain parts of the world. Rising malnutrition will threaten the health of people living in areas where drought is likely to occur.

The images of hunger in Africa due to recent drought episodes are still vivid in our memory. We are seeing the social effects, including riots, of higher food prices and food shortages in a number of developing countries. Social instability combined with what seems to be the end of cheap food have worrisome implications worldwide.

Mitigating Global Warming

Some of the public health effects of climate change can be mitigated. Air conditioning can be used to reduce the impact of rising temperature. Pesticides can be used to control disease-carrying insects and desalination plants can be used to replace lost fresh water due to drought or salt water intrusion.

But an increase in use of air conditioning will increase consumption of energy and create more greenhouse gases. And air conditioning is not always available; especially to the poor, who are the ones most affected by global warming and increased energy costs.

The improper use of pesticides may also expose humans to additional health risks and impact sensitive populations, as experience shows.

Desalinization plants consume energy, impact marine ecology and their product is not truly equivalent to natural fresh water.

Increased flooding and drought have no real countermeasures except to reverse the environmental changes that caused them. As in traditional medicine, the old wisdom applies,  ”An ounce of prevention is better than a pound of cure.”

Prevention Works Best

Perhaps, the best public health approach is to apply preventive measures, even in the absence of clear evidence today that some of these predicted adverse conditions of climate change may not actually occur tomorrow.

Let’s learn from our past mistakes. Those who advocated waiting until the depletion of the Earth’s ozone layer is a clearly proven fact, before taking action, inflicted great damage upon humanity in the form of an increased rate of skin cancer and related economic costs that resulted from society’s failure to act.

At the academic level, we must reach out to policy makers in a positive manner based on interdisciplinary cooperation to help them enact wise policy decisions that will affect public health.

But a science based approach  alone is not enough to turn facts into effective public policy. In fact, the decisions made by policy makers that result in international treaties will help curtail global warming and its effects.

Our response to global warming must come from personal responsibility as well as public policy, however. We each have a moral obligation to humanity to preserve Earth’s ecological systems and conserve its natural resources

Finally, what would we lose if we reduced personal and societal pollution, regardless of the cause of global warming? Most likely, we will lose some of the negative health impacts of pollution and the huge medical cost they entail.

Wouldn’t that be a good enough reason to start cooperating with each other to achieve a cleaner environment and to safeguard our world for future generations?

Possibly, we will have the courage to act wisely in the face of our global challenge. That will be a lasting gain for  all humanity.#

Named by the Journal of Environmental Health as one of 15 Leaders of Environmental Health, Dr. Amer El-Ahraf is a Professor of Health Sciences and Vice President Emeritus at California State University, Dominguez Hills.  Dr. El-Ahraf has a multifaceted interest in environmental and public health that covers scientific, historical and ethical considerations. He is also the recipient of the prestigious Mangold Award for Excellence in Environmental Health. He lives in Huntington Beach.