Study: Planet's Lungs Under Assault From Climate Change

A recent NASA-led study shows how areas of the Amazon rainforest, often referred to as the lungs of the planet, are victims of climate change, suffering persistent effects of droughts, which may change "the structure and function" of these important ecosystems.

The findings, published in the Proceedings of the National Academy of Sciences, used satellite data from 2000 to 2009 to measure rainfall, moisture levels and the forest canopy in southern and western Amazonia.

While climate change came to the shores of the U.S. with Hurricane Katrina in 2005, it brought a megadrought to Amazonia.

"In effect, the same climate phenomenon that helped form hurricanes Katrina and Rita along U.S. southern coasts in 2005 also likely caused the severe drought in southwest Amazonia," said lead researcher Sassan Saatchi of NASA's Jet Propulsion Laboratory. "An extreme climate event caused the drought, which subsequently damaged the Amazonian trees."

But the effects of the severe drought of 2005 were long-lasting, the research team found; they continued until the next severe drought in 2010.

"We had expected the forest canopy to bounce back after a year with a new flush of leaf growth, but the damage appeared to persist right up to the subsequent drought in 2010," said study co-author Yadvinder Malhi of the University of Oxford.

While people may not think of the Amazonia as drought-prone, the area was hit by several smaller droughts recently in addition to the major droughts of 2005 and 2010.

And if climate change continues to bring droughts to the area, the Amazon can expect vast ecological changes.

"Our results suggest that if droughts continue at five- to 10-year intervals or increase in frequency due to climate change, large areas of the Amazon forest are likely to be exposed to persistent effects of droughts and corresponding slow forest recovery," said Saatchi. "This may alter the structure and function of Amazonian rainforest ecosystems."