GENEVA (AP) - Climate change is a major obstacle to a 2004 global treaty aimed at cutting exposure to 21 highly dangerous chemicals, says a new U.N.-commissioned report issued Monday.
The 66-page report says the risks of exposure could increase if more stockpiles and landfills leak due to flooding, or other extreme weather linked to rising temperatures. Chemicals stored in stockpiles or waste dumps to be incinerated or removed later could simply wash away, become more volatile, or escape in the warmer weather through gas emissions, it says.
"Significant climate-induced changes are foreseen in relation to future releases of persistent organic pollutants into the environment ... subsequently leading to higher health risks both for human populations and the environment," says Donald Cooper, the Geneva-based U.N. treaty's executive secretary, in the preface.
The report was presented to experts meeting at a U.N. environment meeting Monday in Nairobi, Kenya. The treaty, known as the Stockholm Convention on Persistent Organic Pollutants, or POPs, is intended to protect the environment and people's health from what it calls very dangerous chemicals that accumulate in the environment, travel long distances by air and water, and work their way through the food chain.
These chemicals pose a known risk to humans and the environment because they persist in people's bodies - damaging reproductive health, leading to mental health problems, or causing cancer or impede growth.
Initially the treaty focussed on 12 chemicals known as the "dirty dozen," such as the widely banned pesticides DDT and chlordane. The use of DDT in sprays to kill malaria-spreading mosquitoes has been allowed under exception in the treaty, but the U.N. says there are good alternatives to combat malaria and hopes to phase out DDT completely by the early 2020s.
In 2009, nine more substances were added, including PFOS, worth billions of dollars in a wide range of uses from making semiconductor chips to fighting fires, and lindane, an insecticide used to combat head lice.
The report says climate warming could result in greater use of some of the pesticides, such as DDT which is produced and used widely for malaria control. Other concerns are that more chemicals will be emitted into the air, the report says, because the vapor pressure increases exponentially with temperature, and added heat will make them more volatile.
The report comes a week after two studies in the journal Nature suggested that extreme rainstorms and snowfalls are growing stronger as greenhouse gases from fossil fuel burning build in the atmosphere.
The treaty's ultimate aim is to phase the chemicals out. Participating countries have one year to say whether they will ban or restrict the chemicals, or whether they will need more time or an exemption. Countries that have ratified the treaty also enact national legislation to enforce the bans and restrictions it imposes.
There are 172 parties to the treaty, that include China and India and most of Europe, Africa, Asia and South America. But a few that have signed on - most notably Israel, Italy, Malaysia, Russia, Saudia Arabia and the United States - have yet to ratify it.
Momentum for the treaty built after scientists grew alarmed at finding high concentrations of the chemicals in the fatty tissues and blood of Inuit Indians in Canada, even though they were thousands of miles away from the production or use of any of the chemicals.