Chris Potter from NASA Ames Research Centre and his colleagues from the California State University and Planetary Skin Institute, modelled the CO2 uptake of the Amazon after last year's record-breaking drought. They based their simulations on satellite data which revealed widespread reductions in the greenness of Amazon forests caused by the drought.

They found that net primary production in Amazon forest areas declined by an average of 7% in 2010 when compared with 2008. This represented a loss of CO2 uptake by vegetation and potential Amazon rainforest growth of nearly 0.5 Pg C in 2010.

"This is roughly equivalent to the damage humans do to the Amazon every year," Potter told environmentalresearchweb. "However, unlike human-caused deforestation, we are hoping this natural deforestation will be reversed quickly as regrowth rate can be dramatic. The Amazon suffered a drought in 2005 and had just recovered by 2008, so we know it can recover."

But Potter points out that last year's drought was more severe than the 2005 event, impacting severely on the Peruvian and Colombian forest. "The eastern Amazon has a longer dry season than the western Amazon which means the trees have deeper roots and are more likely to survive after a drought," said Potter. "The largest effect in 2010 was seen in the western Amazon and these trees may not have such a deep root system. We will have to wait and see how well these trees recover."

The researchers generated their results using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite combined with the Carnegie Ames Stanford Approach (CASA) simulation model. "It is good news that we now have the capability to process this data so quickly," said Potter. "In less than a year after the event, we were able to pinpoint the affected area and this shows that the Earth observing system is working well."

The researchers published their research in Environmental Research Letters (ERL).