WHEN SÃO PAULO went dark at 3pm on August 19th, the city’s 12m-plus inhabitants were stunned by the black cloud that descended on the city. Some took photos of the dystopian scene; others called loved ones in fear that the end was nigh. A popular religious YouTube channel told subscribers that Jesus was returning for the second coming.

Forget the end of days. This apocalypse is man-made. The mid-afternoon darkness, most accept, was caused by rare atmospheric conditions that brought smoke from the fires burning thousands of kilometres away in the Amazonian rainforest.



The cloud, as well as recent alarming data about the extent of this year’s fires, provoked an outcry in Brazil. It also kindled a blazing international row over Brazil’s stewardship of the Amazon. President Emmanuel Macron of France took to Twitter to demand that world leaders discuss the fires at the G7 summit which he is hosting in Biarritz on August 24th-26th. “Our house is burning. Literally,” wrote Mr Macron. “It is an international crisis.” Canada’s prime minister, Justin Trudeau, weighed in, tweeting that he “couldn’t agree more”. Brazil’s far-right president, Jair Bolsonaro, retorted that the Amazon was an “internal issue”. He denounced Mr Macron’s request as evidence of “a misplaced colonialist mindset in the 21st century.”



Mr Bolsonaro, who took power in January, does not believe in climate change. He regards the Amazon as a “virgin” that should be “exploited” for agriculture, mining and infrastructure projects. During the Amazon’s dry season, it is common for farmers to set fires illegally to clear land. But Mr Bolsonaro stands accused of encouraging the wanton destruction of the world’s greatest tropical forest, not least by ordering his environment minister, Ricardo Salles, to sack 21 of 27 senior officials at Ibama, the country’s environmental protection agency.



France and Ireland say they now oppose a trade deal between the EU and Mercosur, a South American trading bloc of which Brazil is the biggest player. The deal, decades in the making, was agreed on in principle this year but has yet to be ratified; it requires the support of each of the parliaments of all participating countries. Claiming that Mr Bolsonaro had lied to him, Mr Macron said: “The decisions and statements from Brazil these recent weeks show clearly that President Bolsonaro has decided to not respect his commitments on the climate, nor to involve himself on the issue of biodiversity.”



Data from the European Union's Earth observation programme show aerosols from the burning forest sweeping from the Amazon down through Brazil’s distant south-east coast (see map).

Brazil’s National Institute for Space Research (INPE) has detected 85% more forest fires this year than in the same period last year. But across the region trends so far (half-way through the fire season) are roughly consistent with the average for the last 20 years. That is not necessarily comforting: rampant deforestation and the practice of slash-and-burn agriculture are to blame. Some researchers note that this year's fire count is higher than it was during the past decade, when rates of deforestation in the Amazon dropped because of stronger enforcement.



Scientists worry that the faster rate of destruction is bringing the Amazon uncomfortably close to the threshold, beyond which deforestation begins to feed on itself, turning much of the Amazon basin into drier savannah known as cerrado.



The Amazon is not the only place where forests are burning: satellite images show extensive fires in central Africa (in line with previous years) and in South-East Asia (slightly more than in the past few years). In the Arctic and sub-Arctic, however 2019 has been usual. Vast fires burning both boreal forest and peat soils have consumed parts of eastern Siberia, Alaska and even Greenland since June.

The fires in the high north are worrying because, as well as trees, they are also consuming peat, releasing carbon that has been trapped over hundreds to thousands of years. What is most disturbing about fires in the Amazon is that the burning is a direct result of human activity. Curbing them depends, in large part, on political will—which Mr Bolsonaro so obviously lacks.



Fighting fire with firings

He and his staff claim the clamour over the Amazon is based on lies. When asked about the fires, he ludicrously accused environmental NGOs of starting the fires themselves in retaliation for funding cuts and in order to make his government look bad. After INPE released data showing increasing deforestation in July, the president claimed the numbers were fake. He then sacked the head of the agency, Ricardo Magnus Osório Galvão, a well-respected physicist.



Such belligerence outrages scientists and environmentalists. “Firing the director is an act of revenge against those who expose the truth,” says Marcio Astrini of Greenpeace, a pressure group. The destruction of the rainforest tends to be out of sight, out of mind for a lot of Brazilians, most of whom live in large cities near the coast. The darkness brought it to their doorsteps. “We don’t have much time,” a columnist wrote in the daily newspaper Folha de São Paulo. “Night will fall on all of us.”

Dig Deeper

Leader: Brazil has the power to save Earth’s greatest forest—or destroy it

Briefing: The Amazon is approaching an irreversible tipping point

Story: The Arctic is ablaze

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