Reduction in Amazon deforestation improves air quality and saves lives

Brazil’s recent success in reducing deforestation rates is saving lives; a new study led by LEAF scientists shows that the recent drop in deforestation has improved air quality across South America, preventing up to 1700 deaths each year.

Over the last 50 years, deforestation of the Amazon has been a major environmental issue. Each year thousands of fires are lit to clear trees and vegetation in order to prepare the land for farming. Smoke from these fires causes a polluted haze over large areas of southern Brazil with serious consequences for human health.

Since 2004 Brazil has achieved dramatic reductions in deforestation rate; between 2001 and 2012, deforestation in Brazil dropped by around 40% (from 37,800 km2 yr-1 to 22,900 km2 yr-1). Together with an international team of collaborators, LEAF scientists from the Institute for Climate and Atmospheric Science (ICAS) examined the impact this success was having on air quality in the region.

Using long-term satellite measurements of aerosol optical depth (AOD), the researchers found that in years with a high deforestation rate there was at least twice as much particulate pollution in the atmosphere. Furthermore, as the deforestation rate has decreased over the past decade, the amount of smoke haze occurring in the atmosphere has also declined.

shutterstock_firecrop-1024x981“We were able to demonstrate that when there is less deforestation in Brazil, there are fewer fires and less smoke in the atmosphere – it is amazing that you can see this effect from space” said Dr Carly Reddington, lead author of the study.

Combining these satellite observations with a global computer model of the atmosphere, the LEAF researchers found that the recent drop in deforestation has reduced the level of harmful particulate pollution over the region by almost one third during the dry season.

Inhaling the particulate pollution generated by fires can have serious implications for human health, causing cardiopulmonary diseases and lung cancer. By calculating how emissions from different sources alter the level of pollution in the atmosphere, scientists can evaluate how dangerous they are for human health. The results from this study indicate that the reduction in deforestation fires is preventing between 400 and 1700 deaths each year across South America.

Dr Dominick Spracklen, a co-author of the study said “The reduction in deforestation in the Amazon has been a huge environmental success story of the past decade. Our work demonstrates that this has led to an unexpected benefit – cleaner air, and that this is saving hundreds of lives each year across Brazil. Cleaner air as a result of reduced deforestation should be recognised as an important benefit to South America.”

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The implications for Brazilian policy makers are stark: reducing deforestation rates has saved lives. Brazil’s original Forest Code (FC), in place since 1965 was controversially revised in 2012 following pressure from agriculturalists. The FC was designed to protect areas of high biodiversity and required private landowners to preserve a high proportion of their land in its natural state. Recent analyses suggest that the revised code may leave additional land vulnerable to deforestation, a finding that could threaten the air quality and human health improvements achieved by Brazil between 2001 and 2012.

Read the original article, published in Nature Geoscience, here.

Post by Cat Scott – University of Leeds.