A drought two years ago triggered fighting, looting and official ‘states of calamity’ across the metropolis, with the army preparing to send in troops. Now, new warnings suggest it could happen again – and point to a surprising culprit

São Paulo could face more devastating water shortages if farmers continue to clear the Amazon forest, warns the utility chief who recently steered the biggest city in the Americas from the edge of drought catastrophe.

Jerson Kelman, president of water company Sabesp, told Guardian Cities he felt a duty to speak out because he was a citizen as well as the head of a company who had seen firsthand how close this metropolis of 21 million people had come to a breakdown.

“We should not transform the Amazon into pastureland,” he said in an interview. “The Amazon creates a movement of water. If you could follow a molecule of water you would see that most of the clouds that are over São Paulo have passed across the Amazon. If the forest is cut, we’ll be in trouble.”

As one of the foremost authorities on water supply and hydropower in Brazil, Kelman’s comments are likely to reignite a debate – resisted by the country’s powerful agriculture lobby – about the link between the world’s biggest forest, climate change and a possible recurrence of the 2014-15 drought.

If things went wrong, we didn’t know what might happen. There could have been riots in the street. Jerson Kelman

The mayor of São Paulo, João Doria, appears to have been persuaded. In an interview with the Guardian he said recognised the importance of the link between the Amazon and the city’s water supply.

“We need to preserve the rainforest to preserve the cycle of rain in central and southeast Brazil,” he said, also stressing the need to reduce demand and promote recycling. His government, however, has made little progress in putting these words into action.

The 2014-15 drought was no ordinary dry period. Over a 12-month period, rainfall was half that of the previous worst year on records stretching back to the early 20th century. By January 2015, the volume of water at the main Cantareira reservoir system was down to 5% – barely a month’s supply.

Dozens of municipalities on the periphery of São Paulo declared “states of calamity”, which allowed for military intervention and emergency funds from the federal government.

Facebook Twitter Pinterest A demonstrator protests over the lack of water in front of riot police in São Paulo’s central Paulista Avenue in February 2015. Photograph: Nelson Almeida/AFP/Getty Images

At Itu – the worst affected city – there was fighting, theft and the looting of emergency water trucks. Many communities’ taps flowed for only a few hours every four days. In some condominiums, residents took buckets from swimming pools to flush toilets, argued over scarce communal supplies and denounced neighbours who washed their cars.

The dystopia even reached the city’s main commercial district around Avenida Paulista, where the swanky Bassano restaurant served guests with plastic plates and cutlery because there was insufficient water supply for dishwashers, and Starbucks only offered bottled beer and cans of Coke because there was not enough water for coffee.

With elections due the following year, the São Paulo state and city governments refused to declare an emergency. But Guardian Cities has learned from multiple sources that the authorities were far more worried than they admitted to the public at the time.

Today there is a mood of calm at the control centre of Sabesp (the Basic Sanitation Company of the State of São Paulo), the water utility that is 50.1% owned by the government. Real-time data displayed on giant screens and a dozen individual monitors show reservoirs are almost back to pre-crisis levels. Automated pumping stations – where water pressure to 220 neighbourhoods can be adjusted at the click of a mouse – are functioning normally.

But asked to recall how different it felt at the height of the crisis, Silvana Franco, a senior official in the control centre, loudly sucks in a breath and shakes her head.

“We were desperate. The reservoir level was just going down and down. We knew that when people don’t have water, they go crazy. We had seen the protests in smaller cities where people were breaking into property to steal water. We imagined what they would be like here with 21 million people. We thought about the hospitals unable to treat patients and children having to stay home from school. It would be chaos.”

She said her boss was so worried his hair turned white.

At the nadir, she said, the military came to check whether the gates and perimeter were secure. This had never happened before, and added to the staff’s fears of being on the edge of an apocalypse.

“There were about five of them in uniform with guns,” she recalls. “They wanted to see how resilient this centre could be because we control the water.”

Facebook Twitter Pinterest A resident walks his dog across the dry bottom of the Paraibuna dam, part of São Paulo’s Cantareira water system. Photograph: Roosevelt Cassio/Reuters

There are limits to what Kelman is able or willing to do about the city’s water crisis. Sabesp, he says, has planted 45,000 hectares of trees on its land and seen the benefits in terms of climate regulation. But it has no authority over Amazon conservation and – because it is a business that must generate profits – there is no incentive to scale back demand (and sales).



In small cities people were breaking into property to steal water. We imagined what would happen with 21 million people Silvana Franco

Sabesp has already dropped the measure that was most effective during the crisis: a financial reward for households that reduced water use. Eighty percent of customers received these incentives, which eased the pressure on the supply system more than other emergency measures such as tapping “dead water” from the reservoirs and interlinking networks. The benefits of these behavioural changes are still evident today as consumption remains more than 10% below pre-crisis levels even though the taps are flowing freely.

On the corporate side of its business, however, Sabesp offers discounts to companies who are heavy consumers. Highlighting the negative impact of market pressures, this controversial policy was introduced to dissuade major clients from digging their own wells or seeking rival suppliers.

Longer term, Sapesb has strengthened drought resilience by focusing on expensive, supply-side engineering works that expand the water footprint of the city.

Facebook Twitter Pinterest An engineer works on a giant pipe at the Jaguari dam, which will create an 11-mile link to the Cantareira system. Photograph: Flavio Forner

At Jaguari reservoir – about two hours drive from the city centre – engineers are putting the finishing touches on a series of giant pumps, pipes and tunnels that will create an 11-mile link to the Cantareira system.



It is one of three mega-projects that will together cost close to R$3bn (£695m) – a huge chunk of Sapesb’s budget – but should provide enough extra back-up capacity to withstand a drought as bad as the one that hit two years ago.

“I know that in three of four years, some politicians will complain we are wasting money on infrastructure that sits idle. People forget easily,” said Kelman. “But now nature has shown us what she can do, the least the population can expect is that decision-makers prepare for rare events … If something worse comes, then we have a problem.”

There is already criticism. Business groups want more of a priority on profitability so a bigger share of Sabesp’s stock can be privatised. Environmental groups are unhappy that more spending on infrastructure means less for sewage treatment and reforestation of areas near water sources that are currently occupied by shanty towns. If these problems could be solved, the city could once again tap its two most central reservoirs – Billings and Guarapiranga – and the river Tiete, all of which are currently too contaminated for use.

Facebook Twitter Pinterest Illegally built housing on the edge of São Paulo’s Billings reservoir. Is it currently too contaminated for use. Photograph: Paulo Whitaker/Reuters

“It’s possible to improve by investing in forests and water treatment, but that’s not happening,” said Malu Ribeiro of the conservation movement, SOS Mata Atlantica. “So of course this [kind of drought] will happen again. The city is still growing. There is more deforestation. More people are living next to water sources. We have learned little or nothing from the crisis.”

Alexis Morgan of the WWF agreed the government’s response has been piecemeal. “A good crisis has gone to waste in terms of the public level response,” he said. “Businesses have learned that demand-side solutions are cheaper and easier. That should be the place to start. But engineers invariably want to put more supply in the system. They fail to recognise that green assets [forests] appreciate over time unlike grey assets [concrete dams]. The government should be looking at both.”

The challenge of building climate resilience is increasingly important and not just in Brazil. According to a new WWF study, São Paulo ranks only eighth in the list of the world’s most drought-vulnerable megacities (population above 10 million). In terms of all cities, the No 1 is Cape Town, which is currently in the midst of its worst ever water shortages and now facing many of the difficult decisions that Kelman and others had to grapple with two years ago.

In São Paulo, a full meltdown was avoided. The most extreme contingency plans were not needed. But it was close. If it had not been for a little rain and some drastic measures, Sabesp could have faced the fury of 21 million thirsty customers.

There is more deforestation. More people live next to water sources. We have learned little or nothing from the crisis Malu Ribeiro

For Kelman, the lessons are fourfold: good supply-side engineering, sensible demand-management through pricing mechanisms, transparency so that the public are on the side of the government in saving water, and accepting that past data was no longer a reliable guide as a result of climate change and land-use change. “The São Paulo experience shows us we can not rely on past assumptions. We need to hope for the best and prepare for the worst.”

He is also looking at the causes. Global climate change and regional deforestation are top of the list.

Kelman says the loss of the Amazon is raising climate risks for São Paulo because the forest helps to circulate water down from the tropics in a process known as evapotranspiration. “Now I enter a minefield,” he says, reflecting the sensitivity of the topic.

There are no statistical models for this yet and the science remains controversial due to the implications for the powerful agricultural lobby, which clears trees for farms, and the hydropower industry, which floods forest for dams.

The best-known exponent is Antonio Nobre, a climatologist at the Space Research Institute who calls the Amazon a “biotic pump” that provides the energy for “rivers in the sky” to flow thousands of miles to São Paulo. Without this booster, he warns, the southeast of Brazil would likely be a desert like many other regions at the same latitude.

Fears of water riots in a country that boasts 12% of the world’s rivers and lakes would once have seemed outlandish, but they are a real and growing concern due to increased consumption and climate disruption on a global and regional level. Kelman believes there are lessons here for the Brazil government and cities across the world.

Among the most important is that past records are no longer a reliable guide to future risks. This came as a shock to Kelman, who wrote his doctoral paper on a historical data analysis – technically known as the stationary series statistical method – which is used to set the parameters for the climate resilience of water and hydropower supply systems.



Facebook Twitter Pinterest A resident of São Paulo’s Brasilandia neighbourhood prepares rainwater to use in the bathroom and to clean the floor of her house. Photograph: Nacho Doce/Reuters

Based on these old statistics, he calculated the chance of a drought like that of 2014-15 as 0.4%, or once in 250 years. It was twice as severe as the planner’s worst forecasts, forcing him into a period of philosophical self-reflection.



“We had excellent data – 83 years worth – and we were prepared for the worst on record,” he says. “But nature showed us that we cannot rely on stationary series statistics as we did in the past. We should prepare for the unknown.”



Another Sabesp official who asked not to be named described the situation as “completely out of control.” A senior government adviser, who also asked for anonymity, concurred. “The risks we discussed in private were far greater than those discussed in public at the time.”



Due to fears of a mob invasion, the authorities established a back-up control centre in a different location. They also installed special pipes to circumvent the main distribution system and ensure water could be directly provided to the 500 most important buildings in the city, including large hospitals, dialysis centres and prisons, even if the rest of the city ran dry. Everyone else, they imagined, would have to take buckets and kettles to city squares where they would have to line up for supplies from water trucks. “It would have been like sub-Saharan Africa,” said one senior official.



This priority list was kept secret. Kelman, the founder of the Brazilian Association of Water Resources, who was drafted in as drought buster in January 2015, said transparency was generally desirable, but in this case the authorities had no choice.



São Paulo – anatomy of a failing megacity: residents struggle as water taps run dry Read more

“It was like wartime. We couldn’t tell anyone which buildings were on the list because the supply might have been disrupted,” said Kelman. “If things went wrong, we didn’t know what might happen. There could have been riots in the street.”

The theory has been attacked. Benedito Braga, the head of the sanitation and water resource secretariat in the São Paulo state government dismissed any link between the drought and the Amazon. “If deforestation was causing this impact then how do you explain the floods that we saw in 2016,” he told The Guardian. “I would say they are both signs of natural variability. 2014-15 was an outlier, not a sign of a trend.”

There is more acceptance among meteorologists who believe the Amazon serves as a link between two key corridors of humidity - the Intertropical Convergence Zone along the equator and the South Atlantic Convergence Zone that stretches down to the southeast of Brazil. The latter is crucial to water supply and the hydropower industry because it brings consistent rainfall for several days which fill the reservoirs far more effectively than occasional drizzles.

“Before 2013, there would be three or four convergence rainfalls in São Paulo every years. But in 2015, there was only one. Last year there was only one and this year there has so far been only one. That means we are still using more water than is naturally replaced,” said Camila Ramos of Climatempo, a private forecasting agency. “If the Amazon forest disappears it would be plausible to assume that the rainfall volumes would drop in Sao Paulo as the the humidity supply towards the southeast might decrease.”

Guardian Cities is in São Paulo for a special series of in-depth reporting and live events. Share your experiences of the city in the comments below, on Facebook, Twitter and Instagram using #GuardianSaoPaulo, or by email to saopaulo.week@theguardian.com