WATER up to the attics on Staten Island. Flooded subway and commuter tunnels. Power lost to 8.5 million homes and businesses. We get it: this storm and its impacts are huge. What we may not be getting is why.

When the debris is cleared away, we will be left with a new high-water mark. On Monday, sea levels in New York City reached about 14 feet above the average low-tide mark; more than 9 feet above the average high; almost 3 feet above the last record, set in 1821.

In the future, we’re going to see more of the same. Satellite measurements show that the oceans are growing; waters are warming. Both factors increase the effects of storms; warmer waters lead to fiercer storms, and sea levels punch up the surges.

A popular myth about sea level rise is that it happens slowly enough that we will have plenty of time to react. Or there’s the blockbuster legend of a thousand-foot wave sweeping Manhattan and changing the world all at once. Both are unlikely.