Scotland's lochs and reservoirs are warming rapidly, report says
- Published
Climate change has caused a rapid warming of Scottish lochs and reservoirs, according to new research.
A report by Scotland's Centre of Expertise for Waters (Crew) found that 97% had seen an increase in temperature between 2015 and 2019.
The researchers have warned that the changes create a greater risk of harmful algal blooms developing.
The Scottish government said it was "vital" that more action was taken to tackle and adapt to global warming.
The report says that most lochs and reservoirs in Scotland warmed by between 0.25C and 1C per year over the four-year period.
However, the temperatures in 9% of them increased by 1C to 1.3C per year.
Researchers said this, combined with changes in rainfall patterns, could mean a greater risk of algal blooms. This could restrict their use for recreation and water supply, and as a safe habitat for wildlife.
They predicted that waters in the south and east of Scotland will warm the most at first, but that the impact will have reached all parts of Scotland by 2040.
The report's lead author is freshwater ecologist Dr Linda May, from the UK Centre for Ecology and Hydrology.
"This research has shown, for the first time, that climate change is already warming our lochs and reservoirs in Scotland, and that this trend is likely to continue," she said.
"It provides early warning of the potential impacts of climate change on biodiversity, water supply and recreational use, and highlights the need for mitigation measures to be put in place as quickly as possible."
These include steps to help prevent the formation of algal blooms, which are mainly caused by phosphorus and nitrogen entering lochs and reservoirs from their catchments.
The report also warns about long-term effects such as "lake heatwaves" - short periods of extremely high water temperatures.
It says these are "likely to push aquatic ecosystems beyond the limits of their resilience, posing a threat to their biodiversity and related benefits they provide to society".
The report also predicts that the temperature in lochs and reservoirs could increase by about 3C by 2080.
Environment Minister Mairi McAllan said the report provided more "worrying evidence" of the impact of climate change on Scottish waters.
"It is vital that we do more to mitigate those impacts; to seek to reduce the pace of warming but also to adapt to it," she said.
"We have committed £243m 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."
Scotland's nature agency, NatureScot, said it was using the £65m Nature Restoration Fund to prioritise conservation efforts.
Crew is a partnership between the James Hutton Institute and Scottish higher education and research institutes, and is funded by the Scottish government.