Mighty Amazon close to running out of water

Desperate times ... canoes stranded in the Amazon River near Santarem in Brazil. The drought has caused many tributaries to completely dry out, isolating some communities.

A state of emergency has been declared in the Amazon River basin, which is suffering its worst drought in 42 years.

More than 1000 towns and hamlets that rely on the river for transport have been cut off as water levels fall, making the river unnavigable.

Several major tributaries, as well as parts of the main river itself, contain only a fraction of their normal volumes of water, and lakes are drying up.

The Amazonas Government secretary Jose Melo said hamlets cut off from the outside world by the low river level were running out of drinking water, medical supplies and provisions.

The region bakes in intense heat of about 38 degrees at this time of year. The level of the Rio Negro, a tributary of the Amazon, has dropped 12 metres since July to just 16 metres.

The Amazon River, South America's largest, has hit its lowest level in the 36 years since records have been kept near its source in Peru.

The Amazon is the second-longest river in the world, after the Nile, but discharges far more water at its mouth than any other.

"This drought and its effects are really shocking," said Carlos Rittl, Greenpeace Brazil's climate campaigner. "Towns are lacking food, medicines and fuel because boats cannot get through."

To make matters worse, as the rainforest becomes increasingly dry, damaging wildfires are regularly breaking out across the region, destroying trees.

Greenpeace blames deforestation and climate change for the drought. "The Amazon is caught between these two destructive forces, and their combined effects threaten to flip its ecosystems from forest to savannah," Mr Rittl said.