Historic: weather patterns similar to what’s causing the drought in California are happening in Brazil. Hudsӧn/flickr, CC BY-NC

Megacity drought: Sao Paulo withers after dry ‘wet season’

Exceptional drought, extreme temperatures, unprecedented drops in reservoir levels and threatening water shortages for millions of people have dominated headlines in California in recent years. Unfortunately, Californians are not the only people being stressed with the “water crisis.”

Citizens of one of the most densely populated areas in South America – the Sao Paulo metropolitan area (SPMA) in southeastern Brazil – are struggling with one of the nastiest water crises in decades.




Blocked storm patterns


Really low: reservoir levels for dams and reservoirs that provide water in Sao Paulo state are at historic lows. Nacho Doce/Reuters


Of course, similar oceanic and atmospheric conditions have occurred in the past and will continue to occur in the future. The problem that we should confront without hesitation is: how can global warming aggravate these extreme conditions, particularly in locations with high rates of urban growth such as Sao Paulo? How fast should governments act and how much should be invested to mitigate these unprecedented conditions?


In the Sao Paulo metropolitan region, the main water supply system, which provides water for about 8.8 million inhabitants, reached critical levels in early 2015. It had only 5% storage of its 1.3 billion cubic meter capacity on January 2015 and 15% at the end of the rainy season in March 2015. An impending ration mandate could leave residents without access to water for a few days a week.

The main water utility has already reduced pressure in the pipes to force conservation, a strategy that has cut off running water to millions of customers for hours and even days, depending on where one lives. Unlike California, isolated rain showers have occurred in Sao Paulo, and the desperate population, particularly in poor districts, has stored the rainwater in open containers and buckets to save it for the days of water shortage. Other citizens are drilling through their basement floors to extract the precious water leaving open wells.

Filling at a public tap: water rationing has turned off regular water services at some homes. Roosevelt Cassio/Reuters

As a consequence, the entire state of Sao Paulo, with a population of 40 million inhabitants, is undergoing a deadly dengue fever outbreak. In the SPMA, where the situation is really dramatic because of the limited access to water, the government created many improvised ambulatories throughout the city to attend the population with symptoms of the disease. Officials go door-to-door searching for infectious mosquito larvae and educating the population about the disease. However, all these measures have proven to be inefficient to control the dengue larvae proliferation.

Two very dry wet seasons based on data going back to 1979. NOAA

What the future will bring for the growing population of the SPMA remains unknown. In the short term, it is possible the blocking conditions that have prevented storms from coming through will become less persistent in the next summer and increase the probability of extreme precipitation in the region. However, the temporary relief will not solve the imminent water crisis in Sao Paulo, nor in California, in the years to come.

Populations and governments in the world need to raise awareness about limited freshwater resources so the present sets the right stage for a sustainable future. No matter where we live or the rate of economic growth of a given nation, populations are, and will always be, vulnerable to water scarcity.

Resilience depends on numerous factors, but how populations will cope with disasters of various magnitudes is largely dictated by political actions, socioeconomic development and education.