amazon Archives

15 July 2016

Drought caused the Amazon to stop storing carbon

The most extensive land-based study of the effect of drought on Amazonian rainforests to date has shown that a recent drought completely shut down the Amazon Basin’s carbon sink. Previous research has suggested that the Amazon – the most extensive tropical forest on Earth – may be gradually losing its capacity to take carbon from the atmosphere. This new study paints a more complex picture, with forests responding dynamically to an increasingly variable climate.

A natural experiment: City in pristine Amazon shows pollution alters ecosystem

Human-made pollutants are changing cloud patterns over the Amazon, altering ecosystems in the process.

Sometimes, the best experiments come ready-made from nature. The Brazilian city of Manaus has a population of almost 2 million people and sits in the heart of an otherwise pristine stretch of Amazonian rainforest, near the place where the Negro and Solimões tributaries fuse to form the Amazon River. New research using the area as a testing ground shows that Manaus city pollutants meddle with the Amazon’s cloud cover, rain and ecosystem, according to scientists who presented the finding at the 2015 American Geophysical Union Fall Meeting.

Rainforests not so rainy: Cutting trees cuts rainfall

Deforestation threatens to upset the delicate water balance within the Amazon rainforest by altering not just ground cover but patterns of rainfall overhead, according to a new study.

Previous research has shown that during the dry season, areas of the Amazon cleared for cattle grazing get more rainfall than the surrounding forest. But most of this research was conducted in the 1980s, when the Amazon was deforested in small patches only a few kilometers wide, said Jaya Khanna, a researcher at Princeton University and lead author of the new study. Khanna’s is the first long-term study of the effects of deforestation on precipitation in the Amazon. Her results, presented at the 2015 American Geophysical Union Fall Meeting, show that rainfall patterns in cleared areas today are vastly different from those in the 1980s.