Fire burning in oil palm plantation in Malaysian Borneo. Photo by: Rhett A. Butler.
Clearing forests and other vegetation with fire in Southeast Asia can kill, according to a new study in Nature Climate Change. The research found that fire-induced air pollution, including fine particulates and a rise in ozone, could be linked to thousands of deaths during El Nino years when dry conditions worsen human-set fires. The pollution was found to be worst over Malaysia and Indonesia, the latter where the vast majority of the fires are set.
“Landowners ignite fires to clear land and manage agricultural areas and, although typically too wet to combust, deforestation and degradation have enhanced the susceptibility of peatland forests (with carbon-rich peat deposits) to human-ignited fire during droughts,” the scientists write.
Peatlands in Indonesia have long been a target of environmentalists, since their destruction releases significant amounts of carbon. But the new research highlights that peatland burning also poses a health risk to millions.
Utilizing satellite imagery from 1997 and 2006, researchers compared land-clearing fires with pollutants in the atmosphere. They found that during strong El Nino years, such as 1997, burning forests and peatlands pushed air quality levels 300 percent past World Health Organization (WHO) limits for about 200 days of the year. The researchers estimated that this could result in the deaths of some 15,000 people. However, even this number, the scientists admit is conservative, especially since they were not able to incorporate the impacts of the pollution on infants and children in the study. In fact during El Nino years, the researchers found that anywhere between 5.4 million to 60 million people were exposed to particulate matter and ozone above WHO recommendations.
Particulate matter and higher ozone ground levels places additional strain on the hearts and lungs, posing particular risk to the elderly and vulnerable.
“Although previous work in Borneo has emphasized the value of avoided deforestation in terms of carbon emissions, it is also important to account for health,” the scientists write. “By demonstrating the direct link between climate variability and health impacts from fire emissions throughout southeast Asia, we offer additional support for policies that use regional climate forecasts to restrict burning during high fire-risk seasons.”
CITATION: Miriam E. Marlier, Ruth S. DeFries, Apostolos Voulgarakis, Patrick L. Kinney, James T. Randerson, Drew T. Shindell, Yang Chen and Greg Faluvegi. El Niño and health risks from landscape fire emissions in southeast Asia. Nature Climate Change. 2012. doi:10.1038/nclimate1658