11-28-07, 12:30 pm

The world today is entering a period of rapid climate change due in large part to increasing the atmospheric concentration of energy-trapping gases. This amplifies the natural “greenhouse effect” that makes the Earth habitable. These greenhouse gases are mostly comprised of carbon dioxide (mostly from fossil fuel combustion and forest burning), plus other heat-trapping gases such as methane (from irrigated agriculture, animal husbandry and oil extraction), nitrous oxide, and other chemicals.

There is very little that is “natural” about this. It is largely the direct and indirect consequence of the plundering of the world’s resources and exploiting the world’s people by multinational corporations maximizing short-term profits. There is little room for long-term environmental stewardship in this endless, unquenchable, scorched earth quest for maximum profits. There are many casualties in this rush to profit – perhaps the most important, ultimately, is the health of the people.

In its Third Assessment Report, released a few years ago, the United Nation’s Intergovernmental Panel on Climate Change (IPCC) stated: “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” Perhaps it would have been more accurate to have said “corporate policies guiding human activities,” but the general concept is evident.


During the 20th century, world average surface temperature has increased by approximately one degree Fahrenheit, and approximately two-thirds of that warming has occurred since 1975. Climatologists, using increasingly sophisticated and accurate methods, forecast further warming and changes in precipitation and climatic variability during the coming century and beyond.

The global scale of climate change differs fundamentally from the many other familiar localized environmental concerns. Worldwide climate change signifies that Earth’s biophysical and ecological systems are being altered at the planetary scale. Among other processes, this is evidenced by stratospheric ozone depletion, accelerating biodiversity losses, stresses on land and marine foodproducing systems, depletion of freshwater supplies, and the global spread of persistent organic pollutants.

The IPCC has estimated that the global average temperature will rise by several degrees Fahrenheit during this century. In addition, the IPCC has projected changes in extreme climate events that include more hot days and heat waves; more intense precipitation events; increased risk of drought; increase in winds and tropical cyclones over some areas; intensified droughts and floods with El Niño events; and increased variability in Asian monsoons. A key question is, “What will be the health consequences in all of this for human beings?”

150,000 Deaths

Scientific evidence relating climatic trends to altered health outcomes remains sparse. This impedes estimating the range, timing and magnitude of likely future health impacts of global environmental changes.

Even so, an initial attempt has been made by the World Health Organization. Analyzing only the better studied health outcomes, the climate change that already occurred since the climate baseline period 1961-1990 was estimated to have caused 150,000 deaths and 5.5 million “Disability Adjusted Life Years (DALYS)” in the year 2000 (DALYs are the sum of the years of life lost due to premature death in the population, in addition to the years of good health lost due to disability).

The IPCC concluded with high confidence that climate change would cause:

• increased heat-related mortality and morbidity,

• decreased cold-related mortality in temperate countries,

• greater frequency of infectious disease epidemics following floods and storms, and,

• substantial health effects following population displacement from sea level rise and increased storm activity.

Both temperature and surface water have important influences on the insects that spread infectious disease. Of particular importance are those mosquito species which spread malaria and viral diseases such as dengue and yellow fever. Mosquitoes need access to stagnant water in order to breed, and the adults need humid conditions to live. Warmer temperatures enhance mosquito breeding. However, very hot and dry conditions can reduce mosquito survival.

Malaria in the US

For North America, the IPCC concluded that insect-born diseases, such as malaria and dengue fever, may expand their ranges in the United States and may develop in Canada. Malaria, today, is mostly confined to tropical and subtropical regions. However, other carriers of human disease in the United States may increase as a result of climate change. Recent analyses have shown that the malaria epidemic risk increases around five-fold in the year after an El Niño event. Rodents, which proliferate in temperate regions following mild wet winters, act as reservoirs for various diseases. Some rodent-born diseases are associated with flooding. Other diseases associated with rodents and ticks, which show associations with climatic variability, include Lyme disease, tick borne encephalitis, and hantavirus pulmonary syndrome (mostly in the American Southwest).

Many diarrheal diseases vary seasonally, suggesting sensitivity to climate. Both floods and droughts increase the risk of diarrheal diseases. Major causes of diarrhea linked to heavy rainfall and contaminated water supplies are: cholera, cryptosporidium, E.coli infection, giardia, shigella, typhoid, and viruses such as hepatitis A. In 2030 the estimated risk of diarrhea will be up to 10 percent higher in some regions than if no climate change occurred.

Extremes of temperature can kill. In many temperate countries, death rates during the winter season are 10-25 percent higher than those in the summer. In July 1995, a heat wave in Chicago caused 514 heat-related deaths and 3,300 emergency hospital admissions. Most of the excess deaths during times of temperature extreme are in persons with preexisting disease, especially heart and respiratory disease. The very old, the very young, and the frail are most susceptible.

Global climate change will be accompanied by an increased frequency and intensity of heatwaves, as well as warmer summers and milder winters. For example, the annual excess summer-time deaths attributable to climate change, by 2050, is estimated to increase several hundred percent, to between 500-1,000 for New York and 100-250 for Detroit.

The effects of weather disasters (droughts, floods, storms and bushfires) on health are difficult to quantify, because secondary and delayed consequences are poorly reported. It is projected that there will be additional numbers of people killed or injured in coastal and inland floods, and would generally cause a greater rise in related diseases.

It is also known that El Niño events influence the annual toll of persons affected by natural disasters. Moreover, in contrast to many other risk factors, climate change and its associated risks are increasing rather than decreasing over time.

Ozone in the Stratosphere and Skin Cancer on Earth

Stratospheric ozone absorbs much of the incoming solar ultraviolet radiation (UVR), especially the biologically more damaging, shorter-wavelength, UVR. We now know that various industrial halogenated chemicals such as the chlorofluorocarbons (CFCs – used in refrigeration, insulation and spraycan propellants) and methyl bromide, while inert at ambient Earth-surface temperatures, react with ozone in the extremely cold polar stratosphere. This destruction of ozone occurs especially in late winter and early spring.

During the 1980’s and 1990’s at northern mid-latitudes (such as Europe), the average year-round ozone concentration declined by around four percent per decade: over the southern regions of Australia, New Zealand, Argentina and South Africa, the figure approximated 6-7 percent. Estimating the resultant changes in actual ground-level ultraviolet radiation remains technically complex. However, exposures at northern midlatitudes, for example, are likely to peak around 2020.

Scientists expect the combined effect of recent stratospheric ozone depletion and its continuation over the next 1-2 decades to be (via the accumulation of additional UVB exposure), an increase in skin cancer incidence in fair-skinned populations living at mid to high latitudes. For the US population this would result in a 10 percent increase in skin cancer incidence by around 2050. There may also be increases in cataracts, adverse consequences for human ability to fight infections, and a reduction in the efficacy of certain vaccines.

Ground-level ozone can damage lung tissue, and is especially harmful for those with asthma and other chronic lung diseases. Sunlight and high temperatures, combined with other pollutants such as nitrogen oxides and volatile organic compounds, can cause ground-level ozone to increase. Climate change may increase the concentration of ground-level ozone.

Another pollutant of concern is “particulate matter,” also known as particle pollution. Particulate matter is a complex mixture of extremely small particles and liquid droplets. When breathed in, these particles can reach the deepest regions of the lungs. Exposure to particle pollution is linked to a variety of significant health problems. Climate change may indirectly affect the concentration of particle pollution in the air by affecting natural sources of these particles such as wildfires and dust from dry soils.

Finally, we have only the slightest understanding about how all the interrelated elements of climate change will ultimately affect the health of the world’s people. But we do know, as the IPCC has noted, there is relationship between human actions like deforestation, migration and land use, the spread of infectious disease, and global climate change.

Class Consequences

It is increasingly evident that all people will not be equally affected by climate change. Working families, the poor, the elderly and the disabled will be affected the most because they have the fewest resources. The wealthy, and the corporations that have plundered the wealth, will be least affected. In the United States, with a public health system starved by war financing at the federal level and corporate tax breaks at the local level, working people are in great jeopardy by the threats of climate change. In the United States, where perhaps a third of the working poor lack real access to health care, they will be the principle victims of injuries and illnesses resulting from climate change.

Now more than ever we need an efficient national health service to provide high quality health care to all the people – no exceptions, no profits, no insurance companies – just the best health care for all the people. This is how the highest rated health care systems around the world are operated, and this is how we can minimize the adverse health impacts of the climate change we know has started.

--David Lawrence is a contributing writer for Political Affairs. Send your letters to the editor to