Brazil faces future of floods, drought

In May and June, heavy rain pushed Brazil’s sprawling Negro River to its highest level in more than a century, causing flooding in Manaus, the Amazon rainforest’s largest city.

At the same time, parts of southern and westcentral Brazil in the Paraná River basin — including Brazil’s largest city of Sao Paulo — have suffered unprecedented drought due to low rainfall.

The disastrous mix of floods, drought and intense downpours could be a glimpse of a potentially dire future as a heating planet and surging deforestation alter long-standing weather patterns throughout Brazil and South America, scientists warn.

Climate shifts could lead to a range of environmental and socioeconomic shocks, from dwindling farm harvests to more destructive forest fires and energy blackouts, climate and forestry experts said.

“What we see now in terms of extremes in temperature and rainfall are perhaps a sample of things that may come if warming continues,” said José Marengo, a climatologist with Cemaden, the Brazilian government’s disaster monitoring centre.

Climate experts say deforestation of the Amazon and the Cerrado — the largest savanna in South America — are key drivers of the country’s changing climate patterns.

“The process (of climate change) is becoming stronger because of human activities,” Marengo said.

In the first six months of this year, the amount of forest cleared in the Brazilian Amazon rose 17 per cent compared to last year, with 3,600 square kilometres disappearing, according to national space research agency Inpe.

Most of the tree losses were to make way for soy farming and cattle rearing, as Brazilian President Jair Bolsonaro focuses on expanding agribusiness as the development model to boost the Amazon region’s economy.

Increasingly heavy rain and floods in the Amazon are linked to atmospheric changes caused in part by ocean warming linked to climate change, said Jochen Schoengart, a researcher with the National Institute for Amazonian Research.

During the first 70 years of water level measurements at the port in Manaus, a big flood was recorded every 20 years, said Schoengart, who specialises in the history of hydrological cycles and forest floods.

What we see now in terms of extremes in temperature and rainfall are perhaps a sample of things that may come if warming continues JOSÉ MARENGO A climatologist