By 2050, 685 million people in cities will face a decline in freshwater availability

The availability of water has historically shaped the wealth and prosperity of cities and nations. Water is not just valuable for domestic and industrial consumption; it is a crucial component in ensuring food and energy security, as well as maintaining important ecological functions. In urban centres, critical services like healthcare, food supply, transportation, energy systems, schools and retail, all depend on a reliable water supply.

Half a billion people already face severe water scarcity all year round. According to the Future We Don’t Want analysis, by 2050, 685 million people living in over 570 cities will face an additional 10 percent decline in freshwater availability, at minimum, due to climate change (see Figure 9). Some cities, such as Amman, Melbourne and Cape Town can experience declines in fresh water availability by between 30 to 49 percent, while Santiago, the capital of Chile, may see a decline that exceeds 50 percent.

By 2050, the global population is expected to reach nine billion, and global water demand is expected to increase by 55 percent. These projections put a considerable strain on existing water resources. The Future We Don’t Want research now suggests that climate change will aggravate the problem dramatically.

By 2025, two-thirds of the world population could be under water stressed conditions, unless substantive action is taken to cut greenhouse gas emissions and adapt to climate change.

Figure 1 – Decline in freshwater in the 2050s – IPCC’s fifth assessment report, while many sub-tropical countries will experience a reduction in water resources, countries in higher latitudes may see an overall increase in renewable water. But even places that receive more water will face water shortages in the short-term as precipitation becomes unpredictable and heavier rainfall events result in increased run-off.

Extreme events muddying water supplies

Climate change is also likely to lead to decreased water quality because it is expected to increase the nutrient content, pathogens, and the sediment levels of surface water. Heavy precipitation events in New York City, for instance, have resulted in increased turbidity levels in many of the city’s reservoirs (up to 100 times higher than prescribed safe limits for source water).

Decreased water availability and quality can have severe health implications among urban communities, especially the poor. According to the United Nations, low-income residents can pay up to 50 times more for a litre of water than their wealthier neighbours. Poverty often means people are faced with a choice: consume untreated water or go thirsty. Water shortages and poor water quality frequently result in health complications such as diarrhoea, which claims 2.2 million lives every year. Rising temperatures and floods also result in increased risk of water and vector borne diseases.

Three years ago, São Paulo suffered two of the driest seasons on record. In 2014, the annual rainfall was half of what the city received in its previous worst year. The megacity of 22 million is on a plateau in Brazil, on the upper reaches of the watershed that flows further downstream and water availability per capita is typically low. By early 2015, the city’s main reservoir Cantareira, which supplies water to 9 million residents had barely a month’s supply of water left.

In São Paulo’s main commercial district, there were news reports of a fine dining restaurant serving food with plastic cutlery and a Starbucks selling canned beverages instead of coffee, because of the water shortage. But while the city’s more affluent citizens were able to invest in additional storage facilities and buy water privately, the poor, living in high altitude settlements in the Periferia bore the brunt of the crisis. The water pressure was simply inadequate to reach their taps. The prolonged drought also resulted in protests and looting in many cities near São Paulo and the central government declared a state of emergency in many of the cities.

Water scarcity is often a catalyst for conflict

As Brazil’s experience reveals, water scarcity is often a catalyst for conflict. In South India, inter-state disputes on water sharing have repeatedly triggered riots. A number of news reports now link recent protests and civil unrest in Iran to persistent water scarcity in the country, which, experts say, is linked to both climate change and poor water management.

Another country that is facing critical water shortages is Iran, where annual rainfall is a third of the global average. A 2013 study by the World Resources Institute ranked Iran as the world’s 24th most water-stressed nation. Overconsumption and poor distribution for over three decades have severely impacted Iran’s available water resources and 500 Iranian cities and towns already face a shortage of drinking water.

Tehran, Iran’s rapidly growing capital, consumes three time more water per person compared to international consumption standards and the country’s Energy Minister Hamid Chitchian has warned that the city would be unable to supply water to all its residents if the city’s population continued to expand at current rate. In 2014, Tehran suffered a prolonged drought with annual rainfall estimated at below 80 percent of the long-term average. According to local newspapers, residents, experienced a drop in water pressure and many citizens installed powerful pumps to draw more water from urban pipelines, further reducing water supply to the city’s poorer residents. Meanwhile city officials noted that over 350 million cubic meters of available surface water in Tehran was polluted by unmanaged waste and unfit for consumption. In 2015 Iran’s former agriculture minister released a report stating that in less than 25 years as many as 50 million Iranians — 60 percent of its current population— would need to leave the country if current conditions persisted.

While Iran is facing a crisis of acute water scarcity, further east in Asia, Metro Manila, the national capital region of Philippines, is susceptible to both excess rainfall, and droughts. Manilla is an emblematic case of how both water scarcity and excess rainfall can deteriorate water availability and quality.

Metro Manila, made of up 16 cities, is among the top 100 most vulnerable urban areas to climate change and it the conurbation is projected to experience increased frequency and intensity in tidal surges, typhoons, storms, and droughts. 16 million people are threatened by around 9 tropical storms that make a landfall each year, resulting in floods, displacement, and disease.The situation is exacerbated by the fact that the city does not have suitable infrastructure in place. As Dr Emma Porio, Science Research Fellow, Manila Observatory and Professor at the Ateneo De Manila University notes, “there is no quality storm drainage system and so flooding is a major problem for metro Manila.”

“Informal settlements are now receiving water, but it is not the best quality and they are paying more…some families pay up to 1,500 pesos for water, but their household income averages 6,000-8,000 pesos.” – Dr Emma Porio, Ateneo De Manila University

In Manilla, as in Tehran and São Paulo, the cities’ poorest residents, living in areas such as Payatas, Muntinlupa, and Las Piñas, are the first to suffer when distributors ration water in a time of crisis. Most of Metro Manila’s water supply comes from a single source, the Angat Dam, making the region particularly susceptible to drought and other climate shocks. Moreover, competing priorities for water during stressed periods has other knock-on implications. Dr Porio explains that during periods of water scarcity, the central government often re-directs additional water to Metro Manilla, diverting it from farmers in neighbouring villages who require the water for irrigation; “Food production is impacted especially in the Bulacan province where watermelons are cultivated, and it is a water intensive crop.”

Recognising that climate change can disrupt already-fragile water systems, cities have been making plans to secure their water reserves. Many city decision makers recognise that a comprehensive approach to water availability needs to incorporate hazard risk analysis, equitable water supply, access to sanitation, and policies that enable collaboration between the government and local communities.

Communities stepping in to resolve water crises

In São Paulo, the city government and some motivated individuals stepped in to resolve the 2015 water crisis. According to Monica Porto, Deputy State Secretary for Water Resources, the water and waste management utility, Sabesp, decided to give a discount to residents on the water bill to incentivise the population to reduce consumption. “If you reduced up to 10 percent you would receive a small discount, if [you reduced] more than 20 percent you received a 30 percent discount.” Consequently, 80 percent of the city residents complied with the scheme, which reduced consumption by an average of 20 percent and eased pressure on the water system.

Three years later, the benefits of the scheme are still evident. Water consumption levels remain 10 percent below pre-crisis levels, even though there currently is sufficient supply. Sabsep is also investing structural changes to improve the water distribution network such as interconnecting different various supply sources to the city, setting up a Water Resources Fund to divert funds from water users to improve watershed management, plugging inefficient pipelines to reduce water losses, and finally giving water collection tanks to people in informal settlements to ensure water storage during water scarce periods.

“Some changes in behaviour and some structural changes in homes and commercial buildings have helped us to not return to our earlier levels of consumption.” – Monica Porto, Deputy State Secretary for Water Resources, São Paulo

A handful of Paulistanos are also making a difference in their city. A news article profiled one local activist who began mapping São Paulo’s network of springs and rivers that exist beneath the city’s buildings and roads. His efforts have highlighted the importance of protecting and using locally available water. Another city resident started a movement called Movimento Cisternas Já or “Cisterns Movement Now.” His group has been installing cisterns to catch rainwater in low income homes. The water can be used for cleaning, in gardens, or to flush toilets. The group continues to provide training to others to install these systems. Bottom-up initiatives such as these often send a powerful message to city residents and the government.

In 2016, citizens of Iran took to online petition platforms to demand the revival of Lake Urmia which has lost over 90 percent of its water. The same year, in Tehran, the government developed information-based advisories to try and change consumption patterns among residents and businesses. The Tehran Municipality, as part of an environmental awareness drive, erected billboards across highways asking people to use water and other natural resources judiciously. The hoardings captured key messages, such as, “About 10-20 liters of water is used in every minute of dish-washing.” Or “Water consumption in Tehran is twice the global norm.” In January 2018, The Tehran Times reported that the Iranian Department of Environment mandated that bottled water be banned though out the country to reduce plastic waste and minimise the water used in bottle production.

Metro Manila has also made significant policy changes toward improving disaster preparedness. Water safety Plans (WSPs) have helped decision-makers identify risks, prioritise investments, and support community partnerships like “Tubig Para sa Barangay” (Water for the Poor) that makes safe drinking water available to individual households. With the availability of piped water, incidents of water-borne diseases among these households are expected to go down. Other practices in Manila include preparing emergency plans to address water quality during extreme floods, and cleaning up the water supply through wastewater treatment.

Dr Porio talks about the efforts of some private sector organisations in Metro Manila. “Among shopping malls there is now a standard procedure of constructing water impounding facilities (rainwater collection systems) underneath the shopping centres.” The Metropolitan Waterworks and Sewerage System has also stated that it is working towards completing the Kaliwa Dam project, which will ensure a second additional source of water supply for Metro Manilla to spread the region’s risk in the face of a water crisis.

Water availability is often the first casualty of any climate impact. If city governments do not act swiftly to meet their mitigation and adaptation commitments under the Paris agreement, water scarcity would lead to cascading socio-economic impacts, hurting urban economies and threatening their very stability.

This content is from 2018. View the full “The Future We Don’t Want” report.