Canada has more lakes than the rest of the world combined.

The defensible version of this claim includes a size threshold. HydroLAKES maps roughly 1.4 million lakes and reservoirs worldwide with areas of at least 10 hectares, equivalent to 0.1 square kilometers. McGill researchers reported that nearly 900,000 qualifying lakes were in Canada, accounting for about 62 percent of the inventory.

That is enough to support the comparison with the rest of the world combined within this census. It does not justify applying 62 percent to every conceivable lake definition. Lowering the minimum size adds vast numbers of small water bodies, and their distribution need not match the distribution of larger mapped lakes.

Canada's abundance has a strong geological explanation. Ice sheets scraped and reshaped the landscape during repeated glaciations, leaving depressions that could hold water. When the ice retreated, many basins filled. The Canadian Shield preserves a particularly extensive landscape of exposed rock, irregular drainage and closely spaced lakes.

HydroLAKES is a geographic database rather than a person counting blue patches on a wall map. Researchers assembled lake outlines from several mapping sources and connected them to a global river network. This makes it possible to compare lake locations and areas consistently and to study how lakes interact with the surrounding drainage system.

The accompanying 2016 research estimated lake volumes and water residence times as well as mapping surface outlines. Because direct depth measurements are unavailable for most lakes, the researchers used statistical methods to extend information from measured lakes to unmeasured ones. A mapped outline and an estimated volume are different kinds of evidence and carry different uncertainties.

McGill's account describes Canada's share as a legacy of glacial scouring and melting at the end of the last glacial period. That explanation does not mean every Canadian lake formed in exactly the same way. It identifies a dominant landscape-scale process, rather than replacing the individual geological histories of hundreds of thousands of separate basins.

Counting lakes also differs from measuring their total water. A country with many small lakes does not automatically hold the greatest lake-water volume. A handful of exceptionally deep or expansive lakes can dominate storage. The researchers noted that the world's ten largest lakes contain about 85 percent of its lake water, showing how unevenly water and lake counts are distributed.

A percentage always needs a defined set of objects. Here the denominator is the lakes represented in a particular global database above a stated mapping threshold. Small seasonal pools, unmapped water bodies and alternative definitions can change that set. Keeping the threshold beside the percentage makes the remarkable result more useful, not less impressive.

Canada’s lake statistic belongs to a map-based inventory, not to an unlimited category of blue features. A ten-hectare cutoff makes the objects comparable across national borders. It also leaves a clear boundary around the conclusion: the Canadian majority applies to qualifying mapped lakes and reservoirs. It does not establish a majority of every wet depression, nor a majority of the planet’s liquid freshwater.