There is a parallel between the present economic crisis and the ecological crisis we are facing. In both cases, we have been living on credit. On both fronts, time has come to pay for the debt.

The negation of environmental costs and our failure to price natural resources into the economy have brought about the climate crisis. The financial collapse represents the same case of overlooking 'negative externalities' in financial reporting, balance sheet and risk assessment. In both cases, we have tried to privatize profits and socialize losses.

After this crisis, society should see the emergence of a new economy, which is less demanding on resources, more frugal, and less brutal with nature.

We already see new models emerging, such as the 'circular economy' where the waste of one industry becomes the raw material of another; the 'performance economy' where people prefer to purchase a usage versus a product; or 'slim cities' versus 'slum cities', where for example water is reused in the same neighbourhood.

In this framework, let us understand the impacts of climate change on water, focusing on two key points. Firstly, we must take a step back on what are the drivers affecting water stress. Secondly, we must look at what we can do, both in terms of demand and supply, and give a message of hope.

There are three main drivers of water stress. The first driver is demography; with our population bound to grow from 6.7 billion today to 9 billion in 2050 (more than 40% increase), it comes to 200,000 additional people per day who will increase the demand for water, mainly through agriculture. As you know, 70% of water use on an average (85% in India) is for agriculture.

Moreover, and from now on, 200,000 people will migrate each day to cities (1,85,000 in developing countries), which means that nearly all the growth of population will happen in cities of emerging countries. Between 2008 and 2030, people living in countries affected by water stress will grow by 1 billion (from 2.9 to 3.9 billion), reaching close to 50% of populations. While urbanization will sprawl, agriculture will remain by far the largest user.

The second driver of water stress is the evolution of diets. On average, a person consume 4 litres of water per day, but water required to produce daily food equals 200 litres per day (50 times more), which is defined as ‘virtual water’. Virtual water content of the average diet is increasing rapidly; 1kg of wheat requires 1000 litres of water, while meat requires 16,000 litres per kg. In effect, per capita cereal consumption is growing very fast as consumption of meat increases, while 80% of cereals are used for feed versus 20% for food. In East Asia alone, cereal consumption is expected to double between 2000 and 2050.

The third driver is climate change, which increases water stress by
a) Shifting patterns of rainfall which causes, for example, monsoon failure in India;
b) Increasing temperature, putting entire regions under stress (in northern India where the number of days of drought has moved from 130 to 170 days; in northern China, or in Australia, Spain or Sub-Saharan Africa);
c) Increasing level of seas, threatening coastal aquifers.

We must find out what can be done, in terms of demand and supply management. The real challenge is to increase systems’ resilience to extreme events. In fact, many impacts that we describe are just extreme examples of challenges already addressed everyday across the world. But, adaptation action has to be done on both demand and supply sides.

On demand management, there will be no water policy independent from agricultural policy. Agricultural water efficiency is a key parameter to reduce water stress. Saving municipal water also has a strong potential. For example, in Casablanca, the savings achieved from leak reduction is equivalent to the water consumption of 800,000 inhabitants.

Increasing supply is the second option. There is huge potential with non-conventional water sources, such as desalination and reuse. Around 2.4 billion people live near the sea, and desalination is already an alternative for more than 200 million people. More than 1% of global drinking water produced is by desalination.

Out of the 368,000 cubic metre per year of wastewater collected in the world, only half is treated and less than 5% is reclaimed. A lot can be done through technology transfer, for example, using membrane/reverse osmosis technology. In India, for example, the total capacity for water being reused in Degrémont wastewater treatment plant in Rithala, New Delhi already amounts to 100,000 cubic metre per day.

In conclusion, the decisions we make on water infrastructure will impact us in the long term. The water infrastructure we build today will be there in the climate of the 22nd century. Therefore, adaptation action must start now.

We should see climate change as an innovation driver, and start by reducing our own emissions. For example, Degrémont wastewater treatment plant already achieves 80% energy autonomy, and the energy positive wastewater plant of tomorrow is on the anvil.

Water companies have to bring their share in the fight against climate change. It is time to be both involved and committed.