Raising the alarm over rising seas

In this Oct. 31, 2012 file photo, a view from the air shows the destroyed homes left in the wake of Superstorm Sandy in Ortley Beach, N.J. Sea levels on Earth are rising several times faster than they have in the past 2,800 years and are accelerating because of man-made global warming, according to new studies. (AP Photo/Mike Groll, File)

Sea level rise is happening. It’s happening faster than it has in centuries. And humans are probably mostly to blame.

Those are the takeaway points from a study released Monday showing that the oceans are rising and warning that humans had better start preparing for the impact of that trend.

Not as in packing your bags and heading to the Midwest, but by developing policies that can halt or mitigate sea level rise.

To reach their conclusions, scientists traced sea levels around the world back nearly 3,000 years and found a sharp spike of ocean rise within just the last few decades.

The report notably does not address extreme events like the October flooding that killed at least 19 people and dealt more than $12 billion in damage across South Carolina. Rather the concern is the everyday flooding that stems from higher average tides.

Those floods aren’t going to displace many people or ruin many cars or cause much property loss. But they can still result in billions of dollars in economic losses from decreased productivity, traffic jams, infrastructure repairs and other related problems.

Even in the best-case scenarios predicted by various reports, Charleston and other coastal cities stand to suffer major blows to quality of life and economic prosperity. The worst-case scenario — three to four feet of rise by 2100 — would be truly devastating.

Of course none of this should come as a surprise to Charleston area residents. The evidence of rising sea levels should be obvious to anyone who lives near or regularly commutes through low-lying parts of town.

And there’s more than just anecdotal proof available. Local tide readings going back nearly a century show that average water levels in Charleston Harbor have increased about a foot since the 1920s.

The number of nuisance high tides has also increased dramatically over the last four decades, according to city data, and trends show no reason to believe that will change in the near future.

On the contrary, the study released Monday suggests that the rate of sea rise might actually accelerate if nothing is done to slow or reverse increasing global temperatures. Much of the 20th century increase in ocean levels had to do with the expansion of water caused by added heat. But going into the future, an increasing portion of sea level rise will be caused by melting ice sheets, the study argues.

That could make a dramatic difference in the rate of change.

Mitigating the worst impacts of climate change and resulting sea level rise is particularly critical in Charleston and other low-lying cities. An agreement reached during an international climate summit in Paris late last year — the most ambitious such accord so far — offers some hope that concerted action is possible.

And Charleston is taking the threat seriously. The city recently released a comprehensive Sea Level Rise Strategy that lays out dozens of different plans to prevent and prepare for the worst impacts of higher waters.

At the local level, implementing those strategies will put Charleston on more solid — if not higher — ground. Coastal residents around the world should push global leaders to address climate change and sea level rise.

The alternative is all wet.