“Our previous research has shown how reduced water levels and rising atmospheric temperatures are also heating our rivers which are creating major challenges for aquatic life, ecosystems, and society. Drought conditions often coincide with high atmospheric temperatures and such trends will become more intense and frequent with climate change.
“The impacts across the UK are already being felt as river and reservoir ecosystems are under stress, including seeing fish needing to be rescued at extremely low river levels with low oxygen levels and hotter waters.
“Extreme heat and drought will also affect our economy as farmers are likely to face lower yields for crops; and emergency work to treat and conserve water will all hit parts of society. Some thermoelectric power plants (coal, gas, nuclear) use water from rivers to cool their systems; and when river temperatures rise, this can force plants to operate at lower capacities or even shut down temporarily. This all underscores the need to mitigate and adapt to human-caused global temperature rises urgently in the UK and, indeed, around the world.”
Dr Shasha Han, Assistant Professor in Hydrology and Water Resources at the University of Birmingham added:
“Looking at long-term historical river flow records across the UK, we can see that many rivers are already experiencing significant changes in extreme conditions like droughts.
“These changes include:
- the amount or volume of water flowing in rivers, with notable reductions during key periods
- the frequency and duration of droughts, which are becoming more common and prolonged
- the timing of drought events, with shifts in when these extremes occur throughout the year
- seasonal shifts, where winter rainfall is becoming more intense, but summer rainfall is decreasing, resulting in drier summers when water demand is high
- spatial variability, with some regions experiencing more pronounced changes than others
“Based on multiple climate model results and future river projections (such as CMIP6 and eFlag project), these changes are expected to continue – and potentially worsen - if greenhouse gas emissions are not reduced.
“Water is such a precious natural resource - it’s the lifeblood of nature. Water conservation is very important and everyone does have a role to play in using water wisely and avoiding unnecessary waste.
“There are practical tips available for households to play their part in water conservation especially at this critical point in the year. Additionally, there is a continuous need to support efforts towards a low carbon future that properly addresses human-caused global temperature rises.”
Dr James White, Research Fellow in Water Sciences at the University of Birmingham said:
“While the heatwaves that we have recently experienced raise our awareness of dry conditions, these typically short-lived events spanning a few days to a couple of weeks reflect abnormally high temperatures. Droughts on the other hand reflect an extreme lack of water compared to ‘normal’ conditions, and often span much longer timeframes where supplies in our atmosphere, rivers, reservoirs, soils and groundwaters are below expected for across multiple seasons or even years.
“This year across the UK, we experienced an abnormally dry spring that depleted water stocks, which in turn set a dangerous precedent for southern and eastern areas also undergoing dry summers. We are becoming all too familiar with hot and dry conditions coinciding, and these ‘compound drought-heatwaves’ inflict “double whammy” effects on our underwater ecosystems, with lower water volumes being warmed more rapidly that creates adverse conditions for our wildlife.
“The Met Office’s ‘UK Climate Projections’ (UKCP18) indicate that warmer, wetter winters and hotter, drier summers will become more frequent with future climate change, as will extremes like floods and droughts.
“Concentrated rainfall across shorter time windows during winter means that less water can be stored in reservoirs and underground aquifers - or in other words, more of this precious resource washes out to sea after inflicting devastating socioeconomic and ecological impacts on its way. This combined with increasing dryness in the seasons to follow makes water security in the context of a growing population and a changing climate a fundamental societal and environmental challenge of today and tomorrow.
“Radical water resource and environmental management actions are therefore urgently required. This includes assessing, and where necessary re-designing, water abstraction licensing practices and dam flow releases to sustainably store and use water, and to help also safeguard ecosystems long into the future.
“Nature-based solutions requires considerable upscaling to more effectively store water that simultaneously mitigates floods and alleviates droughts, and includes interventions like ‘re-wiggling’ our unnaturally straight rivers. Working with nature in this way is becoming increasingly preferred to historic practices like dredging and ‘canalising’ rivers that are short-term fixes, exacerbate downstream issues and are not environmentally friendly. A herculean effort is therefore urgently required to deliver such actions, and requires cross-section and cross-discipline collaborations between environmental regulators, water companies, academics, governments, NGOs and the general public.”
