To illustrate how sea levels rise, imagine yourself sitting in a beach chair at low tide. You might keep dry for a few hours before a wave slides up to your toes. Fifteen minutes later, another washes over your ankles. Ten more minutes, and your knees are wet. High tide is coming in. Not all at once, but incrementally. In surges.

Look no further than the Outer Banks -- another low-lying sand atoll -- for a possible glimpse into the future of our own barrier island. Storm surges from Irene and Sandy mauled chunks off the main highway and carved fresh inlets across the dunes. Emergency repair crews scrambled like ants to build temporary bridges. Houses tilted into the waves. North Carolina must face a hard truth -- its island is cracking up and dissolving into the sea.

Normally, a barrier island responds to rising sea levels by migrating landward. But development and shoreline armoring have anchored the beach in place; the sand cannot roll back, so it erodes. When an island reaches a critical width of 400 to 700 feet, it washes out.

Climate Central, a NASA-funded research group, projects a three-foot storm surge to breach Brevard's coastline by the 2030s. The result of such a scenario would prove catastrophic: one in five homes would be under water.

So how do we avoid the fate of the Outer Banks? In the near term, we spend federal dollars to dredge sand from offshore shoals (Florida has spent about $1 billion on such projects to date), but beach renourishment is akin to mounding sand around your beach chair. As the tide rises, the build-up requires ever-increasing vigilance.

How long can taxpayers subsidize the replacement of the same fragile infrastructure? And what happens when we get slammed with back-to-back hundred-year storms?

Answers won't come easy, or cheaply. With unlimited funds, we could take a proactive approach... raise the island in place, develop new inlets, or plant coastal forests. But these are long-term, costly projects requiring thoughtful budget allocations and 100-year planning.

While it may be economically viable to engineer such systems for densely populated areas like Miami, the probable upshot of a three- to six-foot rise in sea level in Brevard would be a gradual retreat from the barrier island.

For now, an extra few years of beachside occupation clearly justifies the cost of maintaining the sandbar. But at some point, the seas will become too relentless. Our children will likely endure repeated storm surges and flooding. We, as their forbearers, must plan responsibly. Coastal communities need to hold public forums on sea-level rise, and map out the long-term strategies for the future.