The prognosis for Sweden is that a higher mean temperature on average should give larger rainfall with more variations. This is primarily handled as a security problem and is one argument for increasing the spillover capacity in dams. Such investments started about a decade ago as a reaction to the observation that natural flash floods already could put some dams at risk.

There are fairly large reinvestments in hydro power in Sweden and a few new projects but the average production is more or less not increasing due to legal issues. A few years ago our greens managed to start establishing precedence that 5% of the capacity could be spilled for other uses withouth compensation to the powerplant owners and that has started to eat into the production.

I expect that increased rainfall will give a fairly smooth change in the investment levels for handling security and turning water flow into cash flow.

Study: 50-50 chance of dry Lake Mead in 2021 - Climate Change ...
Feb 12, 2008 ... What are the chances that Lake Mead, a source of water for 22 million Americans, ... but rather one that will impact each and every one of us that live in the Southwest. ... which feeds Lake Mead and Lake Powell, is seeing a net deficit of nearly ....

www.msnbc.msn.com/id/23130256/

And don't forget population shifts.