The City of Santa Rosa this week became the latest public entity to declare a hole in its pension liabilities: $100 million.

But what’s $100 million when the federal government is on track to have a 2011 budget deficit of $1.5 trillion, up dramatically from in just a matter of months.

A trillion here, a trillion there and pretty soon you’re talking real money.

So far at least, the unfunded public pension liabilities that are straining budgets across the North Bay and nation – an estimated $200 billion for California – have not raised the kind of public outrage one might expect.

True, it’s an abstract concept. And perhaps many people figure their own retirement is unfunded, so what’s new? And Social Security is going broke, too, right?

But the public pension crisis must be addressed. And the longer the issue is not dealt with, the deeper the hole will become. State and local officials must come to terms with the fact that the current system is unsustainable and begin to make hard choices. Otherwise, every public pension – most of them entirely legitimate – is under threat.

This newspaper has been writing about the looming pension shortfall and the sometimes questionable levels of retirement benefits of public employees since 2005.

Public agencies have been able to cover up the shortfalls for years by cutting services as the pension commitments take up a larger and larger percentage of their budgets.

But the tipping point is near, if it hasn’t already arrived. The day is quickly approaching – if it is not here right now – that a city does not have the money to pay a police officer to patrol the neighborhood where his retired colleague lives.

The changes that must be made have been routine in the private sector for a decade or longer. Defined pension plans like those common in government are becoming rarer by the day. Self-directed plans such as 401(k)s are taking their place.

Government must move in this direction, if not for current employees, then certainly for new ones. Some public agencies have already done so.

And public agencies also must end early retirement benefits that are just too generous to sustain, sometimes reaching into the millions of dollars over the course of a retiree’s lifetime.

The issue clearly is not going away and delaying action will only increase the pain.