Environmental degradation threatens human health

Progress achieved in recent decades, such as the improvement in life expectancy, could be reversed by continuous rapid biodiversity and ecosystem losses, warn two landmark global reports.

By Elton Alisson

Agência FAPESP – Continuous rapid degradation of natural systems throughout the world is a threat to human health and could reverse the progress achieved in recent decades, including improvement in life expectancy.

The warning comes from two recent global reports: one published at the end of June by the Secretariat of the United Nations Convention on Biological Diversity (CBD) in partnership with the World Health Organization (WHO), the other released in July by the Rockefeller Foundation (USA) in collaboration with the UK-based journal The Lancet.

Both reports were launched in Brazil on September 24 during a panel discussion, “Planetary Health: A Challenge for Individual Health,” held at the University of São Paulo (USP) in the capital of São Paulo State.

“The reports complement each other and sum up the state of scientific knowledge about the vital links between health and the environment,” said CBD Executive Secretary Braulio in his presentation to the event.

According to the CBD-WHO report Connecting Global Priorities: Biodiversity and Human Health, environmental degradation has diminished the world’s biodiversity and impaired ecosystem services such as the provision of water, food and clean air.

The decline in these ecosystem services represents a growing risk to human health and the economic sustainability of the planet, according to the report.

“Unlike climate change, which can produce highly visible extreme events, such as more frequent droughts and floods, the loss of biodiversity and ecosystem services due to environmental degradation is a slow, continuous process that may go unnoticed for long periods. Many people are unaware it’s happening,” Dias said.

The report states that environmental degradation has already caused the loss of more than 80% of the world’s grassland species, as well as 90% of its wetlands and large fish stocks.

It has also resulted in the loss of more than 90% of genetic diversity in wheat, rice and fruit species such as apples in recent decades.

“The loss of diversity in crop varieties leaves the world’s population more vulnerable to outbreaks of agricultural pests and a collapse in food supply,” Dias said.

Many of the causes of environmental degradation on a global scale are the same as the threats to human health. They include land use, overexploitation of biological resources, pollution, the spread of invasive alien species, climate change, and ocean acidification.

Ecosystem imbalances due to these forms of environmental degradation cause outbreaks of diseases such as Ebola and Hantavirus infections, the report notes.

“Ecosystem impoverishment leads to the proliferation of organisms that act as hosts or vectors for disease. There’s a clear link between disease and ecosystem imbalance,” Dias said.

The Triatoma infestans bug that transmits Chagas disease, for example, prefers to inhabit palm trees, which are abundant in areas that suffer environmental degradation.

When a forest area is cleared, the palm trees grow back and facilitate proliferation of the insect, Dias explained.

The bacterium that causes cholera (Vibrio cholerae) is present in all the world’s coastal areas and usually causes no problems, but eutrophication due to pollution boosts the amount of plant nutrients in seawater, disturbing the aquatic ecosystem and fueling toxic algal blooms often called green or red tides. This degraded environment kills microcrustaceans.

“The recent outbreak of Ebola virus disease in Africa is also associated with ecosystem breakdown due to human interference,” Dias said.

“Consumption of bushmeat by poor people living in forest areas, owing to a lack of other food sources, has brought them into contact with Ebola virus disease and with other zoonotic pathogens.”

Urgent action

The Rockefeller Foundation-Lancet report, Safeguarding Human Health in the Anthropocene Epoch, stresses that the dangers to the human species due to environmental degradation require urgent collective action at both global and local levels and that cooperation will be indispensable for our survival.

The United Nations Sustainable Development Summit, which was held in September at UN Headquarters in New York and where the Sustainable Development Goals (SDGs) were officially adopted by the 193 countries of the General Assembly, along with the 21st Conference of the Parties (COP21) to the UN Framework Convention on Climate Change (UNFCC) to be held in Paris in December, represent a window of opportunity to place discussion of the impact of environmental degradation on the global agenda, the authors argue.

“Societies must address the drivers of environmental degradation by promoting sustainable and equitable patterns of consumption, reducing population growth, and harnessing the power of technology for change,” said Sir Andy Haines, Professor of Public Health and Primary Care at the London School of Hygiene & Tropical Medicine, in a speech delivered by videoconference during the event.

Among the measures recommended by the report to mitigate the impact of environmental degradation on human health are protecting water resources, combating and reducing food waste, investing in scalable plans and funding models to increase the use of renewable energy sources, and incentivizing regional investment in urban transportation infrastructure.

Investment in urban mass transportation can be beneficial to both human cardiovascular health and environmental health. “Solutions lie within reach and should be based on a redefinition of prosperity to focus on the enhancement of quality of life and delivery of improved health for all, together with respect for the integrity of natural systems,” Haines said.

The meeting was attended by FAPESP President José Goldemberg as well as representatives of the São Paulo State Department of the Environment, USP, Hospital Sírio Libanês and Hospital Albert Einstein.

Goldemberg said scientific research can play a highly useful role in the search for ways to combat the causes of environmental degradation and can also facilitate solutions to problems in human health and other areas.

For example, he said, the discovery that sugarcane straw can be used to generate electricity has led to mechanized harvesting in São Paulo State, ending the once-common practice of setting fire to the crop to facilitate manual cane cutting by burning off the leaves.

“The burning of sugarcane straw emits particulate matter and greenhouse gases. The use of this biomass as an energy source reduces pollution and helps make ethanol plants and sugar mills more profitable,” Goldemberg said.

“By focusing on the causes and consequences of environmental degradation, we can develop more such solutions.”

Connecting Global Priorities: Biodiversity and Human Health can be read at www.cbd.int/health/stateofknowledge/default.shtml.

Safeguarding Human Health in the Anthropocene Epoch can be read at www.thelancet.com/journals/lancet/article/PIIS0140-6736%2815%2960901-1/fulltext.