Finns own more saunas per capita than anywhere else in the world—2 million, or about one per household. While that’s partly cultural, it’s also because of the weather; Finnish winters fall to lows of -35°C (-31°F) in more temperate south, and -50°C in the coldest north.
But if current trends continue, a few decades from now, saunas might not be the must-have refuge they once were. In the past 166 years, average temperatures in Finland have risen by 2°C (3.6°F), according to a new study (pdf) conducted by the University of Eastern Finland and the Finnish Meteorological Institute.
That’s twice the global average increase of 0.75°C in the last century, supporting the theory that warming is more pronounced in higher latitudes, says the study.
Finland’s spike in average temperatures has happened in two phases—from the 1850s to the 1930s, and then from the 1960s to the present. The pause between 1930 and 1960 can be explained mainly by long-term changes in solar activity and cooling caused by post-World War II boom in human-derived aerosols entering the atmosphere, says Santtu Mikkonen, one of the researchers.
The rise in temperatures since the 1960s has accelerated, varying between increases of 0.2°C and 0.4°C per decade. The increases are more acute in November, December, and January, says the study, though springtime months also are rising at faster-than-average rates.
That trend explains why lakes have been freezing over later and later each year, and, in the spring, thawing sooner—as well as why Finnish trees have begun budding earlier and earlier.
In the short term, this isn’t terrible news for Finland’s economy, according to the Finnish government’s Climate Guide website. Warming weather could boost its timber harvest and agricultural output, expand skiing area for tourism, and reduce winter electric bills. However, damage from storms and flooding, as well as increased subsidence, pose a financial threat. At least €550 million ($674 million) worth of property currently sits in flood zones.