By Pip Hinman
Heatwaves and the spread of infectious diseases are likely to result from a business-as-usual approach to greenhouse gas emissions, a report by the world's leading health and climate experts has warned. "Climate Change and Human Health" predicts dire consequences for the health of tens of millions of people — predominantly those in the Third World — if governments — particularly those in the First World — do not take immediate action to reduce greenhouse gas emissions.
Three years in the making, the 262-page report was released on July 14 by the World Health Organisation, the World Meteorological Organisation and the United Nations Environment Program. It was timed to pressure environment ministers gathered at the second conference of the Framework Convention on Climate Change in Geneva July 8-19.
Despite a push, particularly from the Alliance of Small Island Nations, to get ministerial agreement on binding targets to reduce greenhouse gases, the end result was a relatively weak ministerial statement in which a decision on binding targets was delayed for yet another year and a half.
The report, launched in Australia by Greenpeace and the Australian Medical Association (AMA), summarises views on human-induced climate change and uses these to assess the potential health consequences as a result of: changes in temperature and rainfall; changes in the frequency of heatwaves and other extreme weather events; and a rise in the sea level.
It warns that climate change will give rise to an increase in infectious diseases such as malaria, Ross River fever and dengue fever, and will increase the transmission of food- and water-borne infections. Third World populations will be at greater risk of death, injury, starvation and air pollution.
AMA president Dr Keith Woollard commented that the report makes clear "the serious threat to human health posed by global climate change". He said that the report's conclusions needed to be taken seriously if the potential for increased death, injury and malnutrition is to be avoided. The warnings of the adverse impacts on human health were a strong argument, he added, for adopting the principle that "prevention is better than cure".
Greenpeace climate campaigner Erwin Jackson commented that the report "dispels ... one of the myths being perpetrated by some federal government ministers that the threat to Australian industry is greater than the threat to human health".
The WHO-UNEP report notes that due to industrial and agricultural activities which have changed the gaseous composition of the lower and middle atmospheres during the past century, the earth's mean global surface temperature has increased by about 0.3-0.6° C. Computer models predict that this may increase by 1-3° C by the year 2100 if governments stick to their business-as-usual approach.
The models also predict changes in rainfall patterns, including a greater frequency of rainfall and flooding. The report notes that even if greenhouse gas levels were to be stabilised now, the global mean sea level will still rise for several centuries.
Health consequences
The health consequences would be far reaching. The report notes that the most direct effects would be caused by heatwaves, storms and floods, which may increase in frequency and intensity as mean temperatures and rainfall rise.
"Current models indicate that, by around 2050, many major cities could experience up to several thousand extra heat-related deaths annually", the Third World being the most vulnerable.
Other elements of this nightmare scenario include:
- increases in some types of air pollutants, which would increase the incidence of cardiovascular and respiratory disorders;
- changes in the geographic distribution of disease carriers and the behaviour of parasites;
- an increase in the global incidence of malaria by 50-80 million additional cases each year;
- increases in cholera and other food and water-related infections, particularly in tropical and subtropical regions;
- population displacement, loss of agricultural land, salt water intrusion and water supply contamination as a result of a rise in sea levels.
The report also looks at the health consequences of increased ultraviolet radiation, although not a component of climate change. Human-made gases, particularly the halocarbons and nitrous oxide (N2O) have reduced stratospheric ozone levels, which allows a greater portion of solar ultraviolet radiation to reach the earth's surface. This is likely to lead to increased incidences of skin cancer and cataracts.
Studies consistently predict that climate change will have a significant impact on agricultural yield. While some regions may gain, others will lose. "The most negative effects are foreseen at lower altitudes with poorer tropical and semi-tropical countries, especially those reliant on rain-fed, non-irrigated agriculture."
The response of essential food crops to a change in climate will depend on a host of ecological factors including soil erosion, salt water intrusion, the balance between pests and predators and increases in ultraviolet radiation levels. Much of the adverse impact on health would result from the disturbance of complex natural systems.
The report urges governments to protect the health of populations by planting trees and developing climate-adjusted species through genetic engineering; implementing better land-use planning; transferring resources internationally to help the developing world reduce population growth; and reducing consumption patterns and shifting to alternative energy sources in the industrialised nations.
"Wealthy countries cannot expect poorer nations to unilaterally forego the short-term profits to be obtained from use of their natural resources", the report notes. Environmentally sustainable development in the Third World will be possible only if the industrialised world transfers environmentally sound technology there, it concludes.Action needed