For more than a century, for good or ill, New Jersey has led the nation in coastal development. Many of the barrier islands along its coast have long been lined by rock jetties, concrete sea walls or other protective armor. Most of its coastal communities have beaches only because engineers periodically replenish them with sand pumped from offshore.

Now much of that sand is gone. Though reports are still preliminary, coastal researchers say that when Hurricane Sandy came ashore, it washed enormous quantities of sand off beaches and into the streets — or even all the way across barrier islands into the bays behind them.

But even as these towns clamor for sand, scientists are warning that rising seas will make maintaining artificial beaches prohibitively expensive or simply impossible. Even some advocates of artificial beach nourishment now urge new approaches to the issue, especially in New Jersey.

The practice has long been controversial.

Opponents of beach nourishment argue that undeveloped beaches deal well with storms. Their sands shift; barrier islands may even migrate toward the mainland. But the beach itself survives, because buildings and roads do not pin it down.