There is understandingly little knowledge of the phenomenon of global warming and its potential health effects among health professionals. Many are too preoccupied with finding solutions to the myriad of health problems plaguing the developing world to be concerned about geophysical processes. Unfortunately, whether we like it or not, the phenomenon will not just go away and our ignorance may rather encourage practices harmful to the environment. The recent episodes of alternating drought followed by periods of flooding in many parts of the world, Ghana included, bring to the fore the potential devastating effects of climatic and environmental changes.



Many researchers are of the view that global warming has the potential of adversely affecting humans, plants and animals, and the global environment, in synergistic ways involving the interrelationship of many systems. This paper presents an overview of the phenomenon of global warming and its potential health effects. It also outlines a number of plausible responses opened to the health sector to its threat.



Is Global Warming Occurring?

Greenhouse effect is a natural geophysical process which has enabled the earth’s temperature to be on the average, 15°C instead of -18°C. This has been possible through a delicate balance of absorption and radiation of heat involving the sun, the earth’s surface and atmospheric greenhouse gases. Build-up of these gases (carbon dioxide, methane, nitrous oxide and members of the halocarbon family, or CFCs) in the atmosphere, however, alters this natural process leading to the so- called warming of the globe.


Greenhouse gases in the atmosphere have remained fairly constant over the past 20,000 years but since the mid- 18th century, the concentration of carbon dioxide has increased by about 25%, methane has more than doubled, and nitrous oxide and CFCs have seen very rapid increases since 1950. It is also known that there has been an increase of 0.45 °C warming of the earth since the beginning of the 20th century and the six warmest years on meteorological record have been in the 1980s. It is predicted that if current trends continue there will be global warming and this may worsen in the future. What is not certain however is the causal relation with increasing greenhouse gases, the timing and its exact future consequences. Scientists differ on these issues leading at times to heated arguments depending on which side of the coin one finds him or herself.


It is also reasonably known that a number of human activities increase the atmospheric concentration of greenhouse gases. Carbon dioxide, for example, is increased primarily through the burning of fossil fuel, coal mining, deforestation and burning of biomass, as well as pollution from factories and automobiles. Nitrous oxide is released by application of fertilizers, burning of biomass and fossil fuel, in the nylon production and three- way catalytic conversion processes. Methane is released from rice- fields, animal and domestic waste, coal mining and burning of biomass, while CFCs are wholly man-made and are used in refrigeration, automobile, air conditioning and aerosol propellant.


Health Effects of Global Warming

The health effects of global warming may be direct or indirect. The mechanism of direct health effects is not very clear but may be related to heat waves and also to increased absorption of ultra-violet B (UV-B) radiation due to related ozone depletion. They may manifest as increased mortality during summer and increase in cardiovascular, cerebrovascular and some respiratory diseases especially in the elderly, the chronically sick and the very young. It is however predicted that bronchitis and possibly pneumonia may decline with increased temperature in winter while asthma and hay fever might increase due to the seasons, pollen and water vapour concentration and other environmental factors. Greater absorption of UV-B radiation may lead to increase in non-melanoma skin cancers, cataracts, sun-burns, and possible depression of the immune system, especially in light skinned individuals.



Potentially more devastating will be the indirect effects of global warming through its effect on many systems. Food and meat production may decrease with resultant starvation due to a combination of factors including desertification, increasing dryness in grain producing areas, and destruction of crops and animals by flooding. The international food crisis in 2008 which resulted in open riots in many countries is a clear case in point. It is estimated that global warming could cause a sea rise of 0.5- 2meters by the year 2100 and lead to flooding of many coastal cities resulting in loss of life and property, displacement of millions of people, destruction of health and other infrastructure and contamination of fresh water sources- a recipe for the outbreak of major epidemics! What Ghana went through in 2007 in terms of the flooding in the northern parts of the country is a clear reminder to all of us of what global warming can do even in our lifetime. The same happened to Burkina Faso this year requiring a major international intervention.



Another major threat of the phenomenon is the potential redistribution of vectors, disease-causing agents and other parasites- and possibly the diseases they cause- to previously pristine areas due to temperature changes. Diseases like malaria, trypanosomiasis, leishmaniasis, onchocerciasis, yellow fever, dengue and plague which are temperature dependent may be redistributed and become established in some temperate zones which are currently free of the vectors and the disease they cause. Emergence of new or re-emerging diseases with pandemic potential such as the on-going Influenza A (H1N1) cannot be discounted.



Policy Implications for Health Sector

Developing countries have not benefited much from the industrial processes which triggered off global warming, and may feel justly indignant. They cannot ignore their own need for economic growth and yet cannot remain unconcerned as the likely effects of global warming shall be global in scope. They may even be worse off due to their weak economies and poor coping capacity. As a unit therefore, they have to pressurize the industrialized countries to also ratify the Framework Climate Changes Convention signed in Rio de Janeiro in 1993, as well as the Kyoto protocol, to limit atmospheric greenhouse gases. It is a pleasant coincidence that the International Conference on Global Warming and Climate Change for 2008 was held in Accra, Ghana and it is my hope that international community will move concretely forward towards achieving the goals it has set itself. The health sector has an advocacy role to play here. Even as I write this piece another international summit on Climate Change is taking place at Copenhagen, Denmark and it is my hope again that it will not become another talking shop!



At the national level, there is the need for the formulation and implementation of national environmental and climate change policies involving many sectors led by Ministry of Science and Environment. The policies should include energy use, deforestation, recycling, environmental and atmospheric pollution, and sand winning activities, among others. There is also the need for collaboration between the health and other agencies, nationally and internationally, in the areas of epidemiological surveillance of diseases and vectors, monitoring of environmental hazards, information sharing and research.



There is also the need for long term planning at the national level while addressing the myriad of current health problems. The health sector can no longer afford to be interested only in the traditional narrow medical disciplines. Social and behavioural scientists, environmental engineers, epidemiologists and others are all required and have to be planned for in the long term. This may have implications for funding and reprioritization of programmes in the health sector.



At the local level there is the need for awareness creation and policy education as there is widespread ignorance of global warming and climate change and their likely effects. This will enable people to consider the likely environmental impact of their individual and collective activities and also enable them to cooperate with national efforts at reducing anthropogenic greenhouse gases. Lastly, preparedness to deal with disasters will become increasingly important with time and this should be a priority for the health sector and other sectors such as NADMO.



Conclusion

There is reasonable evidence that the concentrations of greenhouse gases are increasing and global warming is occurring. What is in doubt is the correlation between the two processes, the magnitude of the change and the likely health effects in the future. Unfortunately, the world cannot wait to be certain before acting as it may be too late!


More than ever before a collective international effort is needed to avert any global catastrophe. The role of the health sector is to facilitate this collaboration mainly through advocacy, epidemiological surveillance and monitoring, and awareness creation of potential effects of global warming and climate change.