How we are using science to secure water supplies

Contents

• Extreme weather events
• The water cycle and society
• Innovating to improve understanding and preparedness
• Supporting adaptation and mitigation

Climate change has the potential to impact our water resources directly. It influences how and when we use water, along with the infrastructure (and location of that infrastructure) needed to supply the water. All these aspects have potential consequences for future resilience of supply.

Extreme weather events

Human activity is influencing the climate across every part of the world, but not all regions are experiencing this change at the same rate. You will probably already be aware that climate change is already being felt in the UK. The most recent State of the UK Climate Report revealed that 2020 was the first year to have temperature, rain and sunshine rankings all in the top 10.

But what does the future hold for extremes? Broadly speaking, there is a risk of increased hot and dry spells, but also more intense rainfall which may impact water resources across the UK.

Heavy downpours are more likely in warmer climates as warmer air holds more water. This is due to the ‘Clausius-Clapeyron’ relation. This states that for every 1°C increase in temperature, the air can hold an extra 7% of moisture.

Our scientists discovered that towards the end of the century, some parts of the UK could see 40°C days every 3-4 years under a high-emissions scenario. Researchers have shown that the intensity, frequency and duration of extreme weather events is expected to increase as the planet warms.

The most extensive picture yet of how the UK climate could change over the next century is outlined in the UK Climate Projections (UKCP18). The projections show that in the UK:

• summer temperatures could be up to 5.4°C hotter by 2070
• winters could be up to 4.2°C warmer the chance of a summer as hot as 2018 is around 50% by 2050

• sea levels in London could rise by up to 1.15 metres by 2100
  average summer rainfall could decrease by up to 47% by 2070, while precipitation in winter could be up to 35% 

Of course, these changes could significantly impact the water industry and businesses UK-wide. 

The water cycle and society

An important area of our work is understanding how climate change will impact the water cycle, as well as water availability for human use. We work with companies and water users to explore how climate change may impact them. By doing so, we can help them become more resilient to future changes in the climate. 

As more investors focus on sustainability, companies are increasing their reporting of water management and risks this includes water efficiency and emissions targets. With water being more closely monitored, this could result in a reduction in demand. During the COVID-19 pandemic in 2020 our researchers, in collaboration with industry, mapped how water usage changed in the UK. We found most water companies saw an increase in average water consumption during lockdown. The companies covering suburban areas saw the most noticeable increase, whereas city-based companies noted a reduction in water use. 

A primary observation from this data was the increased sensitivity to weather. In fact, the differences between weekday and weekend water consumption largely disappeared. This illustrates how demand can change, so companies need to be prepared to avoid challenges with the supply chain.

Innovating to improve understanding and preparedness

We’ve always worked with organisations to improve understanding and preparedness for the uncertain world we live in. One such project looks at the likely impact of droughts. Using expert knowledge and a wealth of data collected by the Met Office, our scientists have produced a statistical model that provides more accurate gridded rainfall simulations for the east of England. 

The new Advance Meteorological Explorer (AME) can simulate daily synthetic rainfall simulations, providing higher resolution data to plan against than previous industry models (running at monthly timescales). The AME explicitly represents dry, wet and very wet rainfall conditions. With this, it can deliver a more accurate representation of rainfall behaviours and drought conditions.

This is an important achievement because these simulations are already being used to plan future infrastructure developments. This, in turn, improves the resilience of water resources. 

In addition to drought, specialists in our water team have come up with numerous examples of applying statistical extreme value analysis to determine plausible rainfall extremes. The Met Office’s National Climate Information Centre keeps a record of meteorological data dating back hundreds of years. We use this information to see how these records compare to future projections. 

To ensure these models are effective, and to assess the extent of the variability of the current and past climates, we also use hindcasts. Essentially this involves running our DePreSys decadal prediction model from past observations to produce alternative weather scenario. This enables us to assess extremes that could have come into reality under the historical climate. 

It goes without saying that technology allows us to achieve our innovation goals. For this reason, a great deal of our work is based around the supercomputer system. At present, it is able to calculate more than 14,000 trillion arithmetic operations per second. With up to £1.2 billion of funding on the way from central government, we will be able to achieve a higher level of accuracy in forecasting. 

When it comes to the impacts of severe weather, city scale predictions of severe rainfall provide information to town planning authorities so they can make location-specific decisions to help protect life and property. 

Earlier and more accurate warnings of severe weather are an essential part of building a more resilient world in a changing climate.

Supporting adaptation and mitigation

Much of our research and innovation is done in collaboration with industry. We are proud to work with an array of organisations to help them understand the risks associated with high impact weather. This involves reviewing their current adaption plans for climate change and providing weather analytics to see how the ever-changing weather system affects their business. We also assist with policy decision-making, design, build, operation, and decommissioning of large infrastructure projects. Our work helps to ensure resilience now and in the future. 

The Intergovernmental Panel on Climate Change (IPCC) latest report AR6, published on 9 August 2021, shows that it’s undeniable that human influence has warmed the land, ocean and atmosphere. It also highlights that the gap between how unprepared we are for climate change and how prepared we need to be has increased.

As a way of taking action, we will continue to protect the water industry by sharing our meteorological and climate science expertise. We will guide business and industry as a whole towards net zero and a resilient and sustainable future.