How is climate change impacting rainfall intensity?

Among the high-profile flood, heat and fire events in the last few weeks, there have been high profile reports from the Met Office and Intergovernmental Panel on climate change. These reports not only indicate how such extremes are likely to become the ‘new normal’, but also the potential impact of climate change on rainfall intensity.

With increased heating of the atmosphere, greater rainfall amounts can occur. While the future decades are likely to bring hotter and drier summers in the UK, climate modelling is showing that the seasonality of intense rainfall could change. Should this happen, changes in rainfall intensity’s seasonal and regional patterns would affect the management of flood risk and urban pollution management from sewer networks.

A frequent question posed by those dealing with the impacts of these changes is ‘how much change will there be?’ Answering this question is difficult because of the challenges of modelling high intensity rainfall changes. Working alongside the Met Office and Newcastle University, we have been able to derive new uplift (rainfall intensity change) estimates using a state-of-the-art climate model at the Met Office.

A further area of interest for those in the water industry, is ‘what will the future pattern of rainfall changes be like?’ To address this question we are upgrading a tool that provides rainfall time series simulations for different parts of the UK at different times in the future. This work, commissioned by UK Water Industry Research, will output in 2022 and provide UK water and sewerage companies with the ability to model sewer networks for simulated future rainfall time series data. It also uses the Met Office’s convection permitting model used to derive the rainfall uplifts.

Increasingly, we are seeing a need for those impacted by climate change to better understand the risks, and opportunities, of these changes. There is world class climate modelling and science published regularly, but a key challenge is translating that science into meaningful action to become resilient to the changes. It is in this ‘science translation’ area that we at JBA have unique skills, bridging the gap between the science and the impacts.

Want to know more?

For more information regarding this post please contact Murray Dale, or for further details on our work in climate resilience, please visit our dedicated page here.

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