The News That Matters about the Nuclear Industry

Vulnerable to Climate Change – Manaus, Brazil

From heatwaves to hurricanes, floods to famine: seven climate change hotspots  Global warming will not affect everyone equally. Here we look at seven key regions to see how each is tackling the consequences of climate change, Guardian, John Vidal, 23 June 17

“…. Manaus, Brazil

When Carlos Nobre, one of Brazil’s leading climatologists, lived in Manaus in the 1970s, the population was a few hundred thousand and the highest temperature ever recorded in the city had been 33.5C. The city was surrounded by cool, dense forest and the greatest river on Earth. Heat waves were rare and floods regular but manageable.

Today Manaus has more than 2 million people, and it and the wider Amazon region are changing fast. In 2015, Nobre says, the temperature in Manaus soared to 38.8C. “The Amazon is tropical and very hot, but when I lived there the hot spells were rare,” he says. “Now we see many more of them.” Not only that, he says, but dry seasons are longer by a week than they were a decade ago and weather is more erratic.

Nobre notes that tree loss is exacerbating the effects of climate change. “In many parts of continental South America one sees about 1C warming in the Amazon, which can [be] mostly attributed to global warming. In areas like Rondônia, where there has been widespread deforestation, we see an additional 1C warming due to replacement of forest – which is a high-evaporating vegetation – to pasture, which is less evaporating.”

Hot spells in such a humid climate are a real hazard to health. Yet adaptation to climate change in a teeming, poor city like Manaus is non-existent for the many people who must struggle just to survive. For the middle classes, air conditioning is now essential. The most city authorities can do is plant trees to cool the streets and protect the river banks from flooding.

The great uncertainty is how far the drying of the Amazon could affect the rest of the world. “If you change the rainfall in the Amazon, you could transport the impacts very far away,” Nobre says. “According to my calculations, there will be a lot of impacts in southeastern Brazil and also over equatorial Africa and the US. But we cannot pinpoint what will happen.”

Perhaps most ominous is the fact that a positive feedback loop appears to be in play. As the Amazon dries, Nobre says, tropical forest will gradually shift to savanna, releasing carbon dioxide into the atmosphere and further adding to global warming.

“When we see a dry season of over four months, or deforestation of more than 40%, then there is no way back. Trees will slowly decay, and in 50 years we would see a degraded savanna. It would take 100–200 years to see a fully fledged savanna.”

The Amazon then would be unrecognizable, along with much of Earth. …


June 24, 2017 - Posted by | Brazil, climate change

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