More frequent droughts take a toll on forest canopy
By Summit Voice
FRISCO — With climate scientists warning that droughts are likely to become more frequent and severe as global temperatures continue to climb, a recent study led by NASA scientists shows what that could mean for the Amazon rainforest.
After analyzing more than 10 years worth of satellite data collected from over the Amazon region, the researchers said rainforest damage first observed during the start of a megadrought in 2005 persisted the next several years, even as rainfall gradually rose back to average levels. But another dry period that started in 2010 may exacerbate the impacts, suggesting that the Amazon rainforests may be showing the first signs of potential large-scale degradation due to climate change.
The researchers attribute the 2005 Amazonian drought to the long-term warming of tropical Atlantic sea surface temperatures. The drought rate in Amazonia during the past decade is unprecedented over the past century. In addition to the two major droughts in 2005 and 2010, the area has experienced several localized mini-droughts in recent years. Observations from ground stations show that rainfall over the southern Amazon rainforest declined by almost 3.2 percent per year in the period from 1970 to 1998.
“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 Sassan Saatchi ,of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “An extreme climate event caused the drought, which subsequently damaged the Amazonian trees.”
“The biggest surprise for us was that the effects appeared to persist for years after the 2005 drought,” said study co-author Yadvinder Malhi of the University of Oxford, United Kingdom. “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.”
Read more about the study at this NASA website.