GLOBAL WARMING: A HEALTH WARNINGLet there be no doubt, global warming is a killer. It is likely to contribute to or be the direct cause of premature death because of the way in which it causes:
- Loss of human habitat
- Greater incidence of disease and
- Increased ozone production
Loss of human habitat:Most humans can only live in a habitat where very limited climate conditions prevail, where for most of the time it is not too cold (above 0ºC) and not too hot (below 35ºC). Habitat that is wet enough to cultivate food yet dry enough to avoid prolonged high humidity. Outside these conditions, we struggle to survive and do not live for very long. Loss of habitat due to the effects of global warming poses serious threats to our survival.
Humans and, no less importantly the animal and plant species they depend on for food, can only cope with anything outside these parameters for a relatively short period. The effects of global warming and the increasing speed with which it is happening is of immediate and longer term importance to humans.
Global warming produces climate extremes resulting in longer, more frequent periods of severe heat, drought, high winds, precipitation, tidal surges and flooding. Such conditions pose a threat to our health and wellbeing, as evidenced by the 2010 heatwave which struck central Russia, destroying over 20% of the national grain crop and causing the premature death of some 50,000 people. It is nearly certain this event would not have occurred in the absence of global warming.
Heatwave conditions result in a greater incidence of bushfires, accompanied by very dry conditions and high winds. These contribute to contraction of human habitat since they limit reliable food production and water supply needed to sustain a population of any size, particularly very large urban populations. The latter then become dependent on food imported from more distant areas where it can be produced and on water saved and stored from recycling, less frequent rainfall and desalination.
Examples of this are already evident in areas of dense population such as Perth and Melbourne in Australia. These areas are trying to cope with populations growing at such a rate that increased demand is placed on dwindling local water and food supplies. Be it the Central Valley of California or heavily populated N.W. India, sustained food production has become increasingly dependent on unsustainable pumping of groundwater because of diminishing availability of water from rainfall and glacier fed rivers.
Global warming is already causing land based snow and ice to melt much faster than it is being formed with the result that, apart from the Greenland/Antarctic ice caps and some mountain ice cover, the planet is likely to be largely ice free by 2100. The consequences of this have been described elsewhere.
Suffice it to say that this is likely to result in average sea level rises of 1-2 metres by 2100, inundating low lying coastal lands and fertile river deltas inhabited by over 4 billion people, resulting in loss of land currently used for production of the food on which they depend. It will only be possible to maintain food security by reducing exports or by importing more.
If global population growth is not curtailed, the presently low incidence of malnutrition will increase significantly. This will reduce resistance to diseases, particularly vector borne diseases, which either do not occur or are rare at present.
Disease increases:Global temperatures are already rising so fast that some species of plant and animal life have no time to adapt. They face extinction or, at best, much reduced habitat able to support far fewer numbers. For other life forms, rising temperature increases their habitat and this is the case for mosquitoes and ticks, both of which carry diseases and infect humans with them.
These vectors are currently limited to habitat in warmer, more humid parts - in Australia mostly in and north of Townsville on the east coast. They are rare or do not occur further south where winter temperatures fall to levels which kill them. However, as ambient temperatures increase, mosquitoes and ticks will move further south or north and survive winter in places such as Brisbane, the more densely populated southeast corner of Queensland and then move south into New South Wales.
In a few decades from now disease carrying ticks and that harbinger of so many ills, the Anopheles mosquito, will spread to new temperate regions and bring with them serious diseases at present rare or unheard of in those places.
The following Table shows the more common of these, treatment presently available and prognosis for those becoming infected. As mosquitoes and ticks spread further south and north, they will bring diseases for which, at present, there is limited treatment. Many of these diseases either kill or permanently and adversely affect humans, particularly those with impaired resistance to them which, in temperate regions, is the majority.
Encephalitis, Dengue Fever and some forms of Malaria and Tuberculosis are particularly difficult to cure and often prove fatal. Others, such as Asthma are rarely fatal if well managed but are exacerbated, becoming much more serious due to the presence of micro particles in the air caused by bushfires and dust-storms or worse, by an increase of atmospheric ozone.
While diseases causing diarrhea can be successfully treated, they weaken and disable those who contract them, usually from inadequately treated water but also from contaminated food. For example, rising sea surface temperatures can increase the presence of vibrio cholerae found in fish and increase the likelihood of contamination in imported food. Children are more susceptible to cholera than adults and more likely to die without timely treatment.
SOME EXAMPLES OF VECTOR BORNE DISEASE
DISEASE VECTOR TREATMENT OUTCOME
- Ross River Fever Mosquito Antibiotics Disabling for periods up to 6 months. Full recovery with treatment.
- Barmah Forest Fever Mosquito Antibiotics
- Murray Val. Encephalitis Mosquito Antibiotics
- Japanese Encephalitis Mosquito Antibiotics 25 percent mortality, 50percent mentally affected, long recovery
- Malaria Mosquito Some forms treatable, others are resistant. Globally infects 250m. p.a. 0.5pc mortality.
- Dengue Fever Mosquito Treatment of symptoms only 1 per cent mortality if not treated promptly
- Dengue hemorrhagic fever Mosquito Antibiotics treatment of symptoms only 5 per cent mortality if not treated promptly
- Encephalitis Tick-borne Antibiotics Up to 0.5pc mortality
- Lyme Disease Tick-borne Antibiotics Disabling if not treated, full recovery if treated early.
- Nipah Virus Fruit Bats, then person to person Treatment of symptoms only 60 - 80 percent mortality in India and Bangladesh outbreaks
- Tropical Ulcers Infected mud or water Antibiotics Full recovery, can involve scaring
- Cholera Waterborne, infected food Antibiotics and rehydration Full recovery, fatal if not properly treated
- Typhoid Fever Infected food or water Antibiotics Full recovery, rarely fatal unless neglected
- Typhus Fleas, lice Antibiotics 5 percent mortality, depending on age
- Tuberculosis Human to human Resistant types increasing mostly treatable. 20 percent mortality if not effectively treated.
- Asthma Airborne allergens Bronchiodilators, can be cured in the young. May be fatal with complications Sources: WHO, Wikipedia and Encyclopedia Britannica.
The World Health Organisation estimates that global warming is already responsible for 150,000 deaths annually and that half of these occur in the Asia-Pacific region. Mortality will increase as temperatures rise and vectors spread to more populated areas.
A particular danger is posed by the Asian tiger mosquito, Aedes Albopictus, which is now present in the Torres Strait islands and Christmas Island. It is able to survive in all Australian climates and is a dangerous vector. Fruit bats are common in tropical areas but with global warming, their range will spread further south. As carriers of the Nipah and Hendra viruses, they pose a special threat.