Water world: Cacau Pirera in Brazil, when the Rio Negro flooded after heavy rainfall in May
Water world: Cacau Pirera in Brazil, when the Rio Negro flooded after heavy rainfall in May © Lucas Silva/Alamy

Rosivaldo Miranda is on the frontline in the fight against climate change.

The 31-year-old from the Piratapuia indigenous tribe lives in the remotest region of the Amazon rainforest, in the north-west of Brazil, where isolated communities rely on subsistence farming and fishing. Rivers act as the region’s lifeblood, nourishing crops and acting as waterways.

Yet these rivers are also now a threat, as unusually heavy rainfall is causing unprecedented levels of flooding. Along the mighty Rio Negro — stretching from the mountains of Colombia to the rainforest city of Manaus in Brazil — communities are upended almost annually by extreme events.

“It’s not normal,” says Miranda, from his village in Alto Rio Negro, up to four days by boat from Manaus, capital of the state of Amazonas. “We’ve lost crops, bananas, our way of life has been jeopardised. Even fishing — with the raised rivers, the fish become scarce.”

In June, flooding from the Rio Negro, which joins the Amazon river in Manaus, reached its highest level since records began almost 120 years ago. Seven of the biggest floods were in the past 12 years, indicating the “aggravated impact of climate change in the region”, says the Instituto Socioambiental, or ISA, a non-profit that works with threatened communities.

Thousands of homes have been destroyed and 450,000 people — more than 10 per cent of the population of Amazonas — were directly affected, according to the state government.

But the floods are only one factor in the destruction. Rising global temperatures are disrupting traditional ecological cycles and causing sharp changes in weather over the rainforest. Floods may destroy communities one year, but the next year is marked by severe drought.

“The whole system is oscillating like mad between the two extremes,” says Juan Carlos Castilla-Rubio, chair of SpaceTime Ventures, a tech company focused on biomass, energy and water risks. “We are very close to going past the point of no return in several parts of the Amazon. This is driven by a complex combination of accelerating regional warming, fires and deforestation.”

Philip Fearnside, a Manaus-based scientist who was part of the Intergovernmental Panel on Climate Change, which won the Nobel Peace Prize in 2007, adds: “These extreme events can occur without climate change, but you would be missing the message if you stopped there.”

100bn Tonnes of carbon held in the whole Amazon region including its roots, holds 100bn tonnes of carbon

While floods cause the most visible damage, scientists fear that droughts, and the fires that come with them, could have a catastrophic global impact.

A study published in July by UK and Brazilian researchers found that droughts and wildfires after the 2015-16 El Niño warming event killed more than 2.5bn trees and woody vines in the most affected area of the rainforest. By contrast, fewer than 130m trees have died in California since 2010 because of droughts and wildfires, according to the US Forest Service.

Scientists fear that, if tree loss continues, because of both drought and illegal logging, the rainforest will be pushed past a “tipping point” and will no longer sustain its water recycling ecosystem.

The Bobcat Fire burned through the Angeles National Forest in Los Angeles County, California in September 2020 © Kyle Grillot/AFP via Getty Images

This would cause mass death of trees and trigger sharp climate fluctuations across Latin America, jeopardising agriculture and industry. Brazil already faces an acute threat from energy shortages because of a historic drought that has struck the country’s central regions and left hydroelectric reservoirs dry.

Climate scientists also warn that destruction of the rainforest would prompt a massive release of carbon into the atmosphere. “There is a huge stock of carbon in the forest that could be released over a short period of years,” says Fearnside. “The calculation is that all of human activity is releasing 47bn tonnes of C02 or 13bn tonnes of carbon. The whole Amazon, including its roots, holds 100bn tonnes of carbon.”

Erika Berenguer, the scientist who led the drought study, says: “We are going to see large areas of forest burning because it is too hot and too dry.” She points out that “savannaisation” — loss of forest cover — has already begun as trees more typically found in dry climates are starting to spread.

For her, the response should be a global cut in carbon emissions to suppress the rising temperatures that cause severe climatic fluctuations as well as a dramatic reversal of deforestation.

For Miranda, the challenge is to adapt to the disruption wreaked on his remote community by floods and to stave off the risk to their food supply. He has joined up with indigenous researchers, as well as ISA, to monitor flooding in four communities along the Rio Negro and provide early warnings. Such efforts only recently became feasible with the arrival of internet connectivity.

In the long run, Miranda hopes this group, the Indigenous Environmental Management Agents, or AIMA, can influence the creation of state policies designed to ensure food security, which would allow his tribe to continue its rural way of life. “This prepares us for a catastrophe, whether it be floods or drought. It prepares us to face these events and not lose so much.”

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