This is one of the problems with news stories...they put the loss figure in headlines...and no context to balance the story.
Pension funds values can go up and down...and not hurt anybody as long as they can pay out down the road when people retire. And since OMERs membership is not exactly shrinking they are not stuck with more retirees than contributors (I presume). And they can increase contributions in the future. And...I'm sure the government is there to back them and throw more into the pot if needed. So this is really a non-issue I think. Just some sensationalism.