WHO sheds more light on disease threats posed by climate change
Posted on March 24th, 2008By Nathanial Gronewold
Climatewire: The World Health Organization is preparing to launch a global campaign to prepare governments to better recognize and combat the threats to human health made worse by climate change. The move follows new evidence that scientists say shows a stronger connection between climate and health threats than previously recognized.
On April 7, WHO will celebrate its 60th anniversary by issuing the latest annual World Health Report. This year’s report focuses on the effects of changing weather and seasonal patterns — believed attributable to man-made emissions of greenhouse gases — on vector disease spread, food insecurity and increased health vulnerability in the wake of natural disasters or other dramatic weather events.
The new report will be an updated version of an earlier study on health and climate change that WHO released back in 2003, adding new information from later assessment reports by the Intergovernmental Panel on Climate Change (IPCC) and from various scientific studies undertaken since then.
“Up until now people have seen the face of climate change as environmental destruction or biodiversity loss or how it affects animals,” said Carlos Corvalan, a WHO expert based in Brazil’s capital, Brasilia. “But more and more, the evidence is pointing that it is affecting the human species as well.”
While they are keeping a tight lid on the details to be revealed in early April, WHO officials confirmed that a major emphasis of the World Health Report will be on the increased range of disease vectors, animals and insects that carry viruses transmissible to humans. The report will link the expanding range of mosquitoes in Africa and Asia, believed to be caused by warmer weather, to the rapid spread of malaria.
“The species that creates the problems is also going to suffer quite a bit from the impacts of climate change,” Corvalan said.
The new report will also add to evidence that warmer temperatures are having a detrimental impact on agriculture in many parts of the world, leading to worsening malnutrition. Many analysts believe growing food demand and production shortfalls in many countries have contributed to the rapid increases in global food prices witnessed recently.
“Climate change can affect health in many different ways,” said Gregory Härtl, an information officer and project leader at WHO in Geneva. “At the most basic level, when the quality of our air, the cleanliness and availability of our water and the security of our food supply are affected, then the health of us all will be affected.”
The United Nations has designated April 7, the date the World Health Organization was founded in 1948, as “World Health Day.” To mark the occasion, the WHO headquarters in Geneva will issue its flagship “World Health Report” to show that global warming is having a profoundly negative effect on human health. Regional offices in the Americas, East and South Asia and Africa will also issue sub-reports, collecting and summarizing new data gathered in their various jurisdictions.
“Since the third [IPCC] report there have been thousands of papers written, many of them on health, so there has been a great advance in our knowledge about what is happening not just about climate change but also on the health impacts,” Corvalan said in an interview.
Extended summers mean more mosquitos, rodents and ticks
There is strong indication that the most dramatic findings in the coming April report will come from studies showing that climate change is exacerbating the spread of deadly viruses.
WHO published a study in 2003 that said “both temperature and surface water have important influences on the insect vectors of vector-borne infectious disease.” While mosquitoes are most obviously affected by climatic changes, WHO says that rodents and even ticks can also spread their range when temperatures are warmer. For the United States, that means extended summers could be contributing to the spread of Lyme disease in the East and hantavirus in the West.
WHO officials say there is also stronger evidence that climate change is pushing mosquitoes to higher and colder altitudes in the developing world, exposing new populations to malaria, which kills more than 1 million people, mostly children, each year. WHO says the best evidence of the spread of the disease to previously untouched areas comes from Kenya and western China.
“With rising temperatures, the areas in which mosquitoes live and survive increases,” said Härtl. “Specific instances of the spread of mosquitoes to what were colder climes have occurred in China and Kenya.” Currently about 40 percent of the world’s population lives in areas of high risk for malaria contraction, the U.N. estimates.
“Any mosquito-transmitted disease will be similarly affected, such as dengue,” Härtl added.
The impact of climate change on human health is also likely being felt in North America, WHO says. Longer summers and changing weather patterns could be contributing to the spread of mosquito-borne diseases, in particular the West Nile virus, in the United States and Canada.
The upcoming report will also take a fresh look at how dramatic weather is increasing the occurrence of water-borne illnesses. WHO says heavy rainfall and flooding leads to a rapid spread of cholera, giardia, typhoid, hepatitis A and E. coli infection. Scientists believe that warmer ocean temperatures lead to stronger hurricanes and typhoons that dump more rainfall on coastal areas.
Malaria’s spread means more crops fail, food prices rise
The main World Health Report is being drafted as a wakeup call, to gather more public attention to ways climate change is affecting human health. But WHO officials insist that they will not end their efforts with the April 7 global launch. Regional offices are being ordered to organize workshops, assemble commissions or conduct other initiatives to bring together government health agencies, international health experts and WHO officials to develop new policy and coordinate their responses.
“We’re using the reports, using the evidence that we have today to say, ‘What should governments do, what can we compromise to start doing from today?’” said Corvalan. “Our organizations then start to bring the governments together to discuss action.”
Such action could range from aiding governments in increasing the production and availability of food in vulnerable areas, in ways similar to initiatives that the Food and Agricultural Organization is now undertaking, to expanding traditional methods of combating illness and controlling disease spread, especially malaria in Africa.
The latter issue in particular could prove controversial down the road. The malaria problem has gotten so bad in Africa that WHO now advocates controlled indoor spraying of household walls and ceilings with DDT, a dangerous organic pollutant that the agency says is the best proven method for controlling the spread of the deadly disease, at least until a safer alternative can be found.
