by Jack Rosebro
|World Health Organization estimation of deaths caused by anthropogenic climate change up to 2000. Click to enlarge.|
A policy brief from the Lowy Institute in Sydney, Australia entitled “The Sting of Climate Change” argues that global climate change is exacerbating a thirty-year increase in malaria and dengue throughout maritime Southeast Asia and Pacific Islands, and that Australia, as a “fringe country” to mosquito-borne disease, should increase efforts to mitigate the spread of those diseases in both affected areas and areas not yet affected, as well as the potential of transmission to the Australian population from migrating environmental refugees.
Screening, quarantining, and treatment of immigrants from malaria-infested countries is currently carried out in Australia’s Northern Territory. The brief’s author, Dr. Sarah Potter of Environmental Health Branch, NSW Department of Health, recommends that malaria screening be extended to other states, including Queensland and Western Australia, and that dengue screening be initiated, as well.
Dengue is a virus that can lead to dengue hemorrhagic fever, which has an approximate 40% fatality rate if left untreated.
“The Sting of Climate Change” notes that socioeconomic factors can become threat multipliers with regard to detrimental effects of climate change: from 1996 to 2000, for example, central Java, which is Indonesia’s third most populated province with a population of more than 30 million, saw an increase of confirmed malaria cases by an order of magnitude, from 4 cases to 45 cases per thousand persons. The spread of disease was amplified by the 1997-98 Asian financial crisis, which led to significant cutbacks in malaria and other health control programs.
In a separate announcement, Philippines Health Secretary Francisco Duque III said last week that increasing dengue, malaria, cholera, and typhoid fever cases in that country could be attributed to climate change.
Clearly, what was predicted about the impact of global warming is already happening. The different dengue trend, which before it was characterized by peaking every two to three years, now it has always been increasing.—Secretary Duque 
Climate change is projected to humidify some geographic areas and dry out others, with significant rainfall fluctuations in the Pacific caused by the El Niño/Southern Ocean Oscillation (ENSO). Warmer conditions allow most mosquitoes, as well as the malaria parasite, to develop faster; wetter conditions increase lifespan and frequency of breeding. Drought events generally reduce the incidence of vector-borne disease, but can temporarily increase mosquito populations in some areas due to the reduction of mosquito predators and/or an increase in stagnation and contamination of drainage canals and small rivers. Reduced rainfall can lead to an increased reliance on the collection of rainfall in containers for freshwater consumption, which also tends to increase the incidence of disease.
Last year’s Fourth Assessment Report from the Intergovernmental Panel on Climate Change expressed a “very high confidence” that climate change will contract the geographical range for malaria transmission in some areas and expand it in other areas, with the length of the transmission seasons also susceptible to change.
A 2004 World Health Organization study estimates that climatic changes that have been occurring since the mid-1970s caused more than 150K deaths by 2000 through increasing incidences of diseases such as diarrhea, malaria and malnutrition, primarily in developing countries. The study projects a potential doubling of climate-related deaths by 2030.
Malaria already causes as many as two million deaths per year, with half being child deaths, according to the World Health Organization.
 The Sting of Climate Change, Dr. Sarah Potter/Lowy Institute, 2008
 Climate change blamed for increasing number of dengue, typhoid cases, GMA News, 20 November 2008
 Working Group II Report Impacts, Adaptation and Vulnerability: Human Health IPCC Fourth Assessment Report, 2007
 Global and Regional Burden of Diseases Attributable to Selected Major Risk Factors, World Health Organization, 2004