The Press and Journal (Inverness, Highlands, and Islands)
Warning of Scots waters ‘heating up’
Lochs and reservoirs have undergone “rapid and extensive climate change-driven warming” in recent years, according to new research.
A report by Scotland’s Centre of Expertise for Waters (Crew) found that between 2015 and 2019, 97% of Scottish lochs and reservoirs increased in temperature.
Most warmed by between 0.25C and 1C per year, but 9% of them increased by 1C to 1.3C per year.
Researchers warn that these changes increase the risk of harmful algal blooms developing, which could restrict their use for recreation and water supply, and as a safe habitat for wildlife.
Waters in the south and east of Scotland are expected to warm the most at first, but the report warns this climate-related impact will reach all parts of Scotland by 2040.
Environment Minister Mairi McAllan said: “This important research provides yet more worrying evidence of the risks of harm from climate change on Scotland’s water environment.
“It is vital that we do more to mitigate those impacts.
“We have committed £243 million since 2015, through the Agri-Environment Climate Scheme, to support land management practices which protect and enhance Scotland’s natural heritage, improve water quality, manage flood risk and
mitigate and adapt to climate change.”
The report states that short periods of extremely high water temperatures known as “lake heatwaves” are likely to increase in occurrence, exacerbating the adverse effects of long-term warming.
It warns lake heatwaves are “likely to push aquatic ecosystems beyond the limits of their resilience”.
The report makes a number of recommendations to address the impacts of warming, including reducing the amount of phosphorus and nitrogen entering lochs and reservoirs from their catchments, as these are the main driver of algal blooms.
Sources of these plant nutrients, present in
synthetic fertilisers as well as human and animal waste, include farm runoff and waste water discharges.
NatureScot freshwater and wetlands advice manager, Iain Sime, said: “The need for urgent action is clear, and at NatureScot we are using the £65m Nature Restoration Fund to prioritise efforts that support the conservation of our lochs and ponds.”