Background
The authors write that "annual mean temperatures in Finland increased by about 0.7°C during the 20th century," citing Jylha et al. (2004), while noting that under such a warming regime, "both droughts and floods are expected to intensify," which is the claim of climate-alarmists the world over.

What was done
In a study designed to explore the soundness of this contention, Korhonen and Kuusisto analyzed long-term trends and variability in the discharge regimes of both regulated and unregulated rivers and lake outlets in Finland up to the year 2004, using data supplied by the Finnish Environment Institute.

What was learned
The two Finnish researchers report that as "winters and springs became milder during the 20th century ... the peak of spring flow has become 1-8 days earlier per decade at over one-third of all studied sites." However, they say that "the magnitudes of spring high flow have not changed." On the other hand, low flows, in their words, "have increased at about half of the unregulated sites due to an increase in both winter and summer discharges." Nevertheless, they indicate that "statistically significant overall changes have not been observed in mean annual discharge."

What it means
Once again, we have another part of the planet that does not behave as climate alarmists say it should; and, in this case, that misbehavior resides in Finland's hydrological responses to global warming. What is more, the misbehavior occurs at both ends of the available moisture spectrum. At the high end, where flooding may occur, there has been no change in the magnitude of flows that can lead to that unwelcome phenomenon. And at the low end, where droughts may occur, there has actually been an increase in flow magnitude; and that increase either acts to prevent or leads to less frequent and/or less severe episodes of this other unwelcome phenomenon.

Reference
Jylha, K., Tuomenvirta, H. and Ruosteenoja, K. 2004. Climate change projections in Finland during the 21st century. Boreal Environmental Research 9: 127-152.