![Global Warming, Natural Disasters, Climate Change & Health]( "Global Warming, Natural Disasters, Climate Change & Health")
December 26, 2011, 12:00 pm
By Professor Sanath P Lamabadusuriya MBE President, Sri Lanka Medical Association Emeritus Professor of Paediatrics University of Colombo
In the recent past there have been major natural disasters such as floods, droughts, cyclones, earthquakes, landslides, Tsunamis, forest fires etc. affecting many countries. there is increasing evidence that global warming (GW) is directly linked to the increasing incidence of natural disasters, and climate change (CC). Natural disasters and CC have affected millions of lives globally; many epidemics of infectious diseases have occurred, new diseases have emerged, hundreds of thousands have perished and survivors have been left with a heavy burden of physical handicap and psychological problems.
The Industrial Revolution began in the 1800s with the discovery of the steam engine and later the internal combustion engine. the steam engines that are powered by coal and internal combustion engines that are powered by oil, led to an exponential increase in the usage of earth’s fossils during the last two centuries or so. As a result, vast amounts of carbon dioxide (CO2) locked up below the earth were released. with the spread of agriculture and industrialisation, deforestation followed. Many green house gases (GHGs) such as CO2, methane, water vapour and nitrous oxide (N2O) occur naturally in the atmosphere. the synthetic (man made) GHGs that are released as a result of usage of fossil fuels are CO2, methane (CH4), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). These gases are considered to be at least partly responsible for GW, leading to a rise in temperature which may have catastrophic consequences for life on earth. although CO2 has the least GW potential of the 5 gases, it has a lifetime of almost 100 years. in the atmosphere, water vapour, CO2 and other GHGs absorb some of the thermal radiation leaving the earth’s surface. Plants have the capacity to absorb and trap CO2; but with deforestation there is less vegetation around to do so. thus with increasing production of CO2 through utilization of fossil fuels, more transmitted heat from the earth’s surface is trapped leading to GW. the average global temperature has increased gradually during the last two hundred years.
GW has resulted in the melting of the polar ice caps, and rise in the sea levels; this would eventually result in increase of ocean volume at the expense of land volume. GW has a major impact on CC such as increase in temperature, extremes of climate, changes in the quantity and distribution of rainfall (both spatial and temporal) and rise in sea levels. at present there is near unanimous scientific consensus regarding the hazards of GW, and the WHO estimates that CCs of the past 30 years claimed over 150,000 lives annually, obviously not all associated with communicable diseases.
Ecosystems are affected by GW. Higher temperatures enhance microbial proliferation which may ultimately result in outbreaks of food–borne epidemics. Extreme weather related disasters have been followed by food, water and vector–borne disease outbreaks. Climatic variations also have a profound effect on vectors, as they affect reproduction and survival rates. Temperature thresholds of pathogens and their vectors are well defined. a range of epidemics have been associated with CCs such as dengue (Sri Lanka, Pakistan) pulmonary hanta virus syndrome (USA), Rift valley fever (Kenya), meningococcal disease (Saudi Arabia) and leptospirosis (Sri Lanka). Regarding tick–borne encephalitis and Lyme disease, there is an ongoing debate on the precise role of climate influencing a detected increase. Malaria is now spreading to new regions and higher altitudes, however, it remains controversial whether GW is the major cause as such changes are determined by many other factors such as air travel as well.
Emerging infectious diseases are often zoonotic in origin (eg rodent populations may increase with CC). in Sri Lanka the vector of dengue viral fever, the Aedes mosquito, has been detected to breed at higher elevations. GW leads to migration of large communities. When they are displaced as a result of worsening weather patterns, inundations or desertification of cropland, they may import infections as environmental refugees to their often over-crowded home areas, as seen in the African continent. in the summer of 2003, due to an extreme heat wave in South West Europe, when the mean temperature was + 3.50 C above normal (hottest in 500 years), during a 2 week period in August, there were 22,500 to 45,000 deaths. Risk of such heat waves have doubled by 2003 due to human induced CC. there have been milder heat waves in Greece and Italy subsequently. India has experienced 18 heat waves between 1980 – 1998. in India there were 1300 deaths in 1998 and 3000 deaths in 2003. Bangladesh experienced a heat wave in 2001 which caused deaths among rickshaw pullers and metal workers. since 1850, the period between 1995 and 2007 have been the warmest 12 year period.
Changes in complex ecological systems are an indirect effect of CC. the ecology may change resulting in the range and activity of vectors of diseases such as dengue, malaria, avian flu, Chikungunya etc. there would be changes in the environment to facilitate transmission of water-borne diseases such as shigellosis and cholera. Geographic Information Systems (GIS) can be used to store information and integrate data analysis, so as to predict outbreaks of dengue fever and identify potential "hot spots" as was recently carried out in Mawanella.
Possibly there are also few beneficial effects of CC on communicable diseases such as decreased influenza infections in cold climates but data are not conclusive. the highest disease burden is expected to be in regions with the lowest capacity of adaptation according to all predictions and models.
What are the possible solutions to GW, CC and its consequences? the biggest producer of GHGs, which is the USA, is not a signatory to the Kyoto Protocol (KP), regarding it’s prevention. KP is an international agreement setting targets for industrialised countries to cut their GHG emissions. This protocol was agreed and ratified in 1997 by most countries except for USA and Australia. Signing of KP is symbolic and it’s ratification carries a legal obligation and effectively becomes a contractual agreement. the target was to cut their combined emissions by at least less than 5% by 2008 – 2012. Australia signed the agreement later; however, USA has not done so as yet. the main reason for abstinence is due to the potential damage to their national economy. the agreement acknowledges that most developing countries (except China and India) contribute least to climate change, but will quite likely suffer most from its effects. Countries are also able to gain credits for activities which boost the environment’s capacity to absorb carbon. These include tree planting and soil conservation, and can be carried out in their own country, or by that country working in a developing country.
It is heartening to note that in some industrialised countries which are environmentally conscious, Green Parties are emerging; in some parliaments there are elected members. If this movement gathers momentum, there may be a slowing down of GW. in some countries such as Australia, although fossil fuels such as coal are found in abundance, environmentally conscious individuals are using solar panels to generate electricity for their own needs; the excess power that is generated is sold to the national grid. Solar panels made in China are being exported to the USA at a very competitive price. at present generation of power through solar panels is expensive; however in the long run it is cost saving.
Other ways of reducing GW include less use of paper by encouraging communication on-line and re-cycling of paper. Re-cycling of garbage and production of biogas and fertilizer is another example of an environment friendly venture. Concept of minimalisation should be popularised so as to reduce the usage of fuel-powered personal items. As demonstrated in most Western countries and China, cycling should be encouraged by providing cycling lanes in urban areas. If public transport is improved, the need for the use of private motor vehicles would be reduced thereby consuming less fossil fuels. in Colombo, the results of terrible traffic jams during the rush hours is a good example of environmental pollution at it’s worst, reduction of work-hours and wastage of personal finances. Paris has recently introduced electric cars as self driven taxis to reduce environmental pollution.
There cars are powered by a new generation of longer lasting lithium- metal-polymer batteries and this concept is likely to be used in other cities such as London. One approach gaining increasing support is based on the principle that an equal quota of GHG emissions should be allocated for every person on the planet.
Originated by the Global Commons Institute, the proposal, dubbed "contraction and convergence", states that rich countries should "contract" their emissions with the aim that global emissions "converge" at equal levels based on the amount of pollution, scientists think the planet can accommodate. although many commentators say it is not realistic, its supporters include the United Nations Environment Programme (UNEP) and the European Parliament.
Depletion of the ozone layer is another major environmental issue that has received global attention. Stratospheric ozone protects the biosphere from potentially damaging doses of ultraviolet-B radiation (UV-B). Recent depletion of stratospheric ozone could lead to significant increases in UV-B reaching the earth’s surface. UV-B radiation is responsible for a wide range of potentially damaging human and animal health effects, primarily related to the skin, eyes, and immune system. Human exposure to UV-B depends upon an individual’s location (latitude and altitude), the duration and timing of outdoor activities (time of day, season of the year), and precautionary behavior (use of sunscreen, sunglasses, or protective clothing). an individual’s skin colour and age can influence the occurrence and severity of some of the health effects from exposure to UV-B. the Montreal Protocol (MP) was formulated in 1987 to limit the production and consumption of compounds that deplete ozone in the stratosphere. These are chlorofluorocarbons (CFCs), halons, carbon tetrachloride and methyl chloroform. Scientific theory and evidence suggests that once emitted to the atmosphere, these compounds could significantly deplete stratospheric ozone that protects the planet from damaging UV-B radiation. MP decided to phase out these gases by 2000. (2005 for methyl chloroform).
Where does Sri Lanka stand in this scenario? We emit negligible amounts of GHGs but are affected by the consequences of GW as seen by the increase in natural disasters and the changes in the weather patterns during the last few decades resulting in many health related issues referred to earlier.. however we should be conscious about GW, act responsibly to prevent it and set an example to other countries. Harnessing other sources of energy such as hydro, wind, solar, ocean waves and dendro and becoming less dependent on coal and oil should be the way forward. the government could promote such ventures by offering tax incentives for such projects. Investment in nuclear energy remains controversial because of potential environmental hazards. in our country much publicity is given to an annual day of "Tree Planting". Such ventures should not only be symbolic but sustainable so as to increase the forest cover and greenery in general. Deforestation, if essential, should be properly planned and carried out with the involvement of environmentalists. Illegal felling (logging) of forest trees, which is rampant, should be curtailed immediately.
Movements of tectonic plates result in earthquakes and tsunamis. These disasters are probably not related to GW. however these disasters also result in thousands of deaths, spread of disease, physical and psychological problems as well. Earthquakes are associated with outbreaks of rabies in endemic countries due to dogs becoming more aggressive.
It is encouraging to note that global agreements such as KP and MP have been introduced to protect the planet’s inhabitants from environmental hazards. We sincerely hope that the planet’s biggest polluter (USA) would become more globally sensitive and become a signatory to KP before too long.
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