Our changing climate means more flooding and more droughts. But what else does it mean for our water, and what should we do now to ensure we all have safe, clean and affordable water in the future?

Climate change and its impacts have been the focus of growing public concern for many years.

The impacts of climate change are likely to vary across Europe, but will generally result in warmer, drier summers and milder, wetter winters. These shifts in our weather directly impact the water cycle and will significantly affect water service providers both in terms of raw water resource quality and availability as well as the operation of waste water infrastructures.

The response of water services to climate change must, therefore, include both mitigation (reducing the climate change footprint of water operators) and adaptation (becoming resilient to the effects) measures.

Climate change may also affect some of the parameters that serve as the basis for planning and investment decisions geared towards safe and efficient water operations. Given that water service providers must make long-term plans and investments, immediate action is essential in order to be future-ready. But there is one thing that we are sure of; we will all need safe, clean and affordable drinking water.

Drinking water suppliers in most regions will nevertheless have to adapt to a seasonally or intermittently diminished availability of water.

Higher temperatures in lakes and reservoirs lead to more evaporation and therefore less available water during hotter months. Less rain during this time of the year may also cause water shortages, putting significant pressure on existing water supplies while leading to higher concentrations of contaminants. Increased temperatures also lead to the proliferation of algal bloom and waterborne pathogens that have to be removed in water treatment plants.

During winter months, increased rainfall may improve water supply levels in some regions. This can, however, result in short term high concentrations of pollutants in surface water and groundwater sources as rains and floods can flush pollutant build-up into receiving surface waters in the form of runoff, necessitating more treatment in water sanitation plants. Large amounts of water in reservoirs will help reduce concentration levels however.

Higher temperatures also mean trouble for waste water treatment. Hotter weather can increase the production of hydrogen sulphide (H2S) gas in sewer systems increasing corrosion and odour issues.

More extreme weather events such as flooding will likely cause greater CSO (combined sewer overflows) and increase the potential for excess water to bypass waste water treatment plants in the event of storms or floods. Water containing human and industrial waste enters rivers and other water bodies untreated, resulting in negative health and environmental consequences including contamination of drinking water sources and beach closures. Flooding can also cause damage to water treatment infrastructure and collection facilities, which reduces their efficiency.

There is no one-size-fits-all solution for climate change adaptation. Differences in climate change effects and vulnerability to these impacts can vary greatly between regions and even within the same supply system. This is the case for urban drainage systems and treatment of waste water as well.

Climate change is a real threat and will impact our water services. We have to act now in order to have safe, clean, reliable and affordable water in the future. Acting now, and adapting measures to mitigate climate change is preferable to dealing with the consequences.

The water sector is key in the climate change discussions, and we are ready to accept our responsibilities in meeting the challenges it poses.

Nature-based solutions are one path to increasing our resilience. Working with nature will help reduce the impacts of climate change on our water services and increase the quality of life for everyone. Citizen initiatives, and local, national, and international legislation will also all play a significant role in creating a resilient and flexible water sector.

Climate change is a real threat to this precious resource that we all depend on. The water services sector has the potential to play a vital role in global warming adaptation. We cannot act alone. We must have the support of industry, consumers and governments in order to face our future in a holistic way.