Human health under threat from ecosystem degradation: WHO

Human health is under threat from ecosystem degradation, and threats are particularly acute in poorer countries, according to a report published Friday by the World Health Organization (WHO).

The report, Ecosystems and Human Well-being: Health Synthesis, represents an attempt to describe the complex links between the preservation of healthy and biodiverse natural ecosystems and human health.

"Over the past 50 years, humans have changed natural ecosystems more rapidly and extensively than in any comparable period in human history," said Lee Jong-wook, director-general of WHO.

"This transformation of the planet has contributed to substantial net gains in health, well-being and economic development. But not all regions and groups of people have benefited equally from this process," he said.

According to the report, approximately 60 percent of the benefits that the global ecosystem provides to support life on Earth (such as fresh water, clean air and a relatively stable climate) are being degraded or used unsustainably.

In the report, scientists warn that harmful consequences of this degradation to human health are already being felt and could grow significantly worse over the next 50 years.

"The benefits should be acknowledged," said Carlos Corvalan, WHO 's lead expert on the report. "But these benefits are not enjoyed equally. And the risks we face now from ecosystem degradation, particularly among poor populations directly dependent on natural ecosystems for many basic needs, has to be addressed."

Ecosystem services are absolutely vital to preventing disease and sustaining good health, the Health Synthesis report underlines. Many important human diseases have originated in animals, and so changes in the habitats of animal populations that are disease vectors or reservoirs, may affect human health, sometimes positively and sometimes negatively.

Intensive livestock production, while providing benefits to health in terms of improved nutrition, has also created environments favorable to the emergence of diseases, the report notes.
Trends ranging from forest clearance to climate-induced habitat changes also appear to have impacted on certain populations of mosquitoes, ticks and midges, altering transmission patterns for diseases like malaria and Lyme disease.

Pressures on ecosystems could have unpredictable and potentially severe future impacts on health, the report states. Regions facing the greatest present-day risks, meanwhile, include sub-Saharan Africa, Central Asia, parts of Latin America, and certain areas in South and Southeast Asia.
One of the most serious problems is nutrition. Degradation of fisheries and agro-ecosystems are factors in the malnutrition of some 800 million people around the world. At least an additional billion people experience chronic micronutrient deficiency.

Safe drinking-water is also serious. Water-associated infectious diseases claim 3.2 million lives, approximately 6 percent of all deaths globally. Over one billion people lack access to safe water supplies, while 2.6 billion lack adequate sanitation, and related problems of water scarcity are increasing, partly due to ecosystem depletion and contamination.

Solid fuel dependency is another problem. About 3 percent of the global burden of disease has been attributed to indoor air pollution, a major cause of respiratory diseases. Most of the world's population uses solid fuels to cook and heat, a factor in deforestation.

The Health Synthesis Report is WHO's contribution to the broader Millennium Ecosystem Assessment, a four-year series of studies and reports, involving over 1300 scientists, considering impacts on human well-being, past, present and future.

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