Negotiators at the Paris conference on climate change forged a path last month to slow global warming. The effects of their actions will take years to appear.

Long Island is dealing with the reality of climate change now. And we’re going to have to make our own decisions.

Our coastal communities already are threatened by sea-level rise and the likelihood of more serious storms. Sandy laid waste to parts of our region, and we’re still rebuilding. And we’re still vulnerable to the next big storm.

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For decades, we’ve punted on an answer. We rebuild a dune, move around the sand, spend tens of millions of dollars, protect homes and businesses on the front line . . . then watch the protection eventually wash away. It’s a nightmare of rinse and repeat.

It’s long past time to confront uncomfortable facts. We have unwisely built in some very risky places. Protecting everything forever — not just on Long Island but in Queens, Brooklyn and lower Manhattan — would require immense amounts of money. What to save? At whose expense? When does it make more sense economically to buy out a vulnerable building and remove the risk, and what about the property owner’s heartache? Some properties have been purchased to return to nature, some protective marshlands will be restored, but what’s the overall plan?

That tension underlaid the debate that took place over what to do about 13 exposed waterfront motels in Montauk, and the vibrant downtown behind them. The Army Corps of Engineers is spending $9 million on a short-term solution that is unfortunate but now necessary, more than three years after Sandy. Huge bags of sand placed on the beach will act as a bulwark, but will increase erosion in front of them and to the west.

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A longer-term solution involves pumping sand from offshore to widen the beach, which the Army Corps apparently will propose this winter as part of its plan to gird Suffolk from Fire Island to Montauk. But officials say the pumping is three to five years away. And, like any sand solution, it’s not permanent.

But it will buy time to do the homework to answer the tough questions. We must seize the opportunity. What to do about Montauk’s motels, part of the economic engine on the East End? What about the vacation homes on Fire Island? What about Long Beach, Jones Beach, Mastic Beach and all their South Shore brethren? What about the dunes along Asharoken Avenue, the Village of Bayville and the rest of the North Shore? What about the hundreds of rotting bulkheads that are the only protection for many waterfront properties? What’s the overarching plan?

Residents of two special districts in Sagaponack and Bridgehampton paid for their own protection, voting after Sandy to tax themselves $26 million to rebuild a 6-mile stretch of beach in front of their homes. Most of Long Island can’t do that.

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East Hampton Town, which has jurisdiction over Montauk, has a $250,000 state grant to plan for its future. It intends to produce new estimates of erosion rates and sea-level rise, determine potential hazards and what-ifs, and involve town residents in a discussion about being proactive — as Supervisor Larry Cantwell puts it, “how, when and where to rebuild now.”

But with more than two dozen municipalities strung along the South Shore from Montauk to Manhattan, each controlling its own fiefdom but affecting its neighbors, a more comprehensive approach is needed. We don’t have a local government mechanism to do that. And the federal government seems incapable of doing it; the Army Corps was authorized to improve the 83 miles of coastline from Fire Island to Montauk Point in 1960, and nothing has happened in 56 years.

It’s time to consider a different model, one like the California Coastal Commission, which partners with municipalities to plan and regulate development and other coastal activities. It’s an independent state agency set up by a voter referendum in 1972, and it largely works. Whatever the model, it’s up to Gov. Andrew M. Cuomo and the State Legislature to make something happen in the legislative session that began last week.

None of this is easy. These decisions go to the heart of what it means to live on Long Island — where we reside, where we work, where we relax and play. But the degree of difficulty is no reason to avoid the task. The longer we wait, the harder it gets. And it’s been too long already.