Persistent Organic Pollutants

Climate change increases vulnerability of planet

UN study finds climate change increases exposure to POPs and heightens their toxic effects on humans and the environment

Climate change increases the planet’s vulnerability to persistent organic pollutants (POPs), a UN research team concluded in a major study.

The study, ‘Climate Change and POPs Inter-Linkages,’ was conducted by climate and chemical experts from 12 countries, and is the first systematic and authoritative review of the impact of climate change on the release of POPs into the environment, their long range transport and environmental fate, and human and environmental exposure.

POPs are substances that are persistent and toxic and can affect generations of humans. Exposure to POPs is known to effect health and can be the source of cardiovascular disease, metabolic disorders and cancer. Some POPs are also considered to be endocrine disrupters and by altering the hormonal system, can also damage human reproductive and immune systems.

Global warming increases emissions of POPs and exposure via the food chain

Climate change, and the changes in temperature, impact the exposure of humans and wildlife to POPs and will also affect biodiversity, ecosystems and vulnerability.

Among the major conclusions of the study, increased emissions and the increased availability of POPs to enter the food chain leads to bio-magnification which happens when certain chemicals become concentrated in organisms as they move into and up the food chain, threatening the health of humans and animals.

"Climate change increases the planet's vulnerability to persistent organic pollutants, by increasing emissions and the bio-availability of POPs, and thus the potential for bio-magnification through the food chain, one of the chief pathways of human exposure to POPs," said Katarína Magulova, programme officer of the Secretariat of the Stockholm Convention.

Global warming contributes to a higher frequency of extreme weather events, which can cause severe flooding, triggering the secondary emissions of POPs.

The unusually high monsoon rains responsible for the catastrophic 2010 summer flooding in Pakistan were part of an anomalous weather pattern across Asia causing floods and landslides in China and North Korea and heavy rains in Indonesia, a UNEP Global Environmental Alert Service reported in November 2010. Not surprisingly, the heavy rains coincided with a heat wave in Russia.

Floodwaters triggered by extreme storm events can also inundate agricultural land where stockpiles of obsolete POPs pesticides banned under the Stockholm Convention are awaiting removal.

Large stocks of obsolete pesticides are situated in areas where there are intensive cash crops and agricultural activities. Stockpiles located in towns or villages and near water bodies pose potential human health and environmental risks.

"The increasing frequency and severity of tropical cyclones and flood events are increasingly putting at risk stockpiles containing thousands of metric tonnes of obsolete POPs pesticides and the low-lying agricultural communities where these chemicals are typically stored," warned Achim Steiner, UN Under-Secretary General and Executive Director of the United Nations Environment Programme (UNEP).

"The heavy monsoon flooding in Pakistan this year was an unprecedented natural disaster. Over 20 million Pakistanis were affected and 1.6 million families suffered major disruptions to their homes and livelihoods," said Cameron Munter, the US Ambassador to Pakistan.

"Floods and other natural disasters can quickly defeat existing infrastructure and release dangerous and obsolete pesticides into the environment where people and animals are directed exposed," Ambassador Munter added.

The United States has given more than US $600 million to support Pakistan's flood relief.

Higher temperatures can make wildlife more sensitive to exposure of certain pollutants. In the Arctic region, climate change can alter the exposure levels of marine mammals, such as seals or the polar bears, through a variety of means including changes in long-range atmospheric and oceanographic transport along with the melting of the ice caps.

DDT is a persistent organic pollutant which the global community hopes eventually to eliminate from the planet. However, the expected increase in the incidence of vector-borne diseases, such as malaria, associated with climate change may lead to enhanced demand for and release of DDT in some regions.

The investigators identified key knowledge gaps, including the lack of long-term monitoring data to evaluate the impact of climate change on changing POP emissions and concentrations and the need for climate change mitigation options to fully take into account influences associated with the production and distribution of unintentionally produced POPs.

They called for improved coordination between policy makers who address climate change and those who address the management of POPs both domestically and internationally.

The outcomes of the study are expected to result in policy recommendations on how to mitigate the impacts of POPs under the planet's changing climate.

The study was conducted with partners from: Arctic Monitoring and Assessment Programme (AMAP), University of Berne (Switzerland), Environment Canada, Fisheries and Oceans Canada, Health Canada, European Monitoring and Evaluation Programme (EMEP), Indian and Northern Affairs Canada, International POPs Elimination Network (IPEN), Laval University (Canada), Masaryk University (Czech Republic), Norwegian Institute for Air Research (NILU), Norwegian University of Science and Technology, Trondheim (Norway), Peking University (China), Stockholm University (Sweden), Swiss Federal Institute of Technology (Switzerland), Technological University of Monterrey (Mexico), University of Bern (Switzerland), University of Concepcion (Chile) and University of Texas School of Public Health (USA).