Researchers from McGill University have published the most complete database of lakes to date, providing a tool to scientists that assists understanding of the impact lakes have on hydrological cycles globally.
The study reveals that Canada has 8,798,000 freshwater lakes—10 hectares more than every other country on Earth combined.
The research, Estimating the volume and age of water stored in global lakes using a geo-statistical approach, was published in Nature Communications in December. In the abstract, the researchers described the knowledge of lake distribution, volume, and residence as crucial in understanding the interaction lakes have in the Earth system and point to the inconsistency and lack of previous models.
“Lakes are changing, in a changing world,” said senior author Bernhard Lehner, an associate professor in McGill’s Department of Geography to the university’s newsroom. “Some are disappearing as there is less water to keep them filled, others are created or growing in regions where there is more rainfall. So we need a good inventory of the current status of lakes to understand and monitor their changes and the effects that this may have for our global environment.”
The data strongly informs, “Spatially explicit knowledge of all these parameters is crucial for understanding and modelling a wide variety of Earth system processes and interactions with the environment, including hydrological budgets; carbon or methane exchange rates; sediment trapping; heat fluxes and coupled weather and climate effects; dissolved silica retention; the cycling of pollutants and nutrients; as well as associated ecological processes such as lake productivity; species richness; food chain dynamics; and inland fishery yields.”
Other assets derived from the research will assist carbon modelling. Current models based on estimating “fluxes in and out of inland waters default to multiplying an average flux by the total surface area of lakes in a region.“ The datasets collected by Lehner, et al. allow more reliable modelling of flux, eliminating the need to use proxy information for large-scale processes that the new data allows for.
The entire database can be downloaded for free from HydroSheds.org.
World’s lakes with surface areas of 10 hectares or greater. Concentrations of lake water are shown in darker blue. Hydrolab, McGill University.