As those of us in Charleston and other coastal cities gradually brace for rising seas, heavier rains and other challenges posed by climate change, it’s important to bear in mind that we can control only so much. That’s not to say we shouldn’t work urgently to adapt as best we can; just the opposite. We have to work even harder on the strategies we have because there are still so many things we don’t know — many of which could make our situation even more dire.
Ice melting hundreds or even thousands of miles away can have a big impact here in the form of rising sea levels, and our warming planet is speeding up all this melting. A 2019 study of 19,000 glaciers worldwide that tracked measurements over the past several decades found that ice is melting almost everywhere, generally more quickly than previously thought; the world is losing an estimated 369 billion tons of glacial ice each year, a rate five times faster than what was recorded in the mid-20th century.
But the story is actually much more complicated than the bathtub concept expressed in this simple formula: warming air + glaciers = more ocean water and higher seas.
As Post and Courier reporter Tony Bartelme explains in a special report on Greenland, the climate and geological changes on the world’s largest island (Australia is larger but is considered a continent rather than an island) can be expected to have an outsized impact on South Carolina’s coast, compared to other parts of the world.
That’s partly because Greenland’s massive ice sheet, which covers 80% of the country’s land mass about a mile deep on average, has its own gravity, which pulls water in the North Atlantic toward it. This actually increases the current sea levels near it but lowers them farther away, in places such as Charleston, which is about 3,000 miles to the south. So its melting glaciers not only add more water to the ocean but also reduce the island’s gravitational pull that draws water away from Charleston (much like the moon draws it away, except Greenland’s pull isn’t cyclical).
Unfortunately, that’s not all. The warming planet actually causes ocean water to expand, so there’s not only more water in the ocean, but it needs more room and climbs up shorelines.
And Greenland’s heavy ice sheet not only exerts gravity, but the sheet’s meltwater also affects the massive ocean currents that scientists call the AMOC, short for Atlantic Meridional Overturning Circulation. The AMOC includes the Gulf Stream, which flows past the East Coast so forcefully that it actually pulls water away from our beaches, keeping our current sea level about 3 feet lower than it otherwise would be. Or at least that’s normally the case. As Mr. Bartelme explains: “Greenland’s massive ice melt has tossed a giant wrench into this important system. In 2009, when the AMOC slowed, sea levels in New England suddenly rose 5 inches for about a year. Scientists say the AMOC system has slowed by 15%, and by some measures is at its weakest point in 1,600 years.”
So Greenland’s near-term fate will greatly affect us, much more than we realized only a few years ago.
As Josh Willis, a climate scientist with NASA’s Jet Propulsion Laboratory who has been working in Greenland, told Mr. Bartelme: “The gravity issue may represent a small increase in Charleston’s sea level, let’s say 20%, and ocean currents might be another 20%, and thermal expansion (of the oceans) another 20%, but once you add up these and other 20 percents out there, you have a problem.”
These findings, most made or confirmed during the past decade, should humble us in several ways, beginning with the reality that we don’t know what else scientists might discover in the coming years. And while these findings certainly paint a more dire portrait, it likely will take a long time before a majority of us embrace them, especially given how divisive our nation has become. As much as we’re learning, researchers still have no consensus on one of our biggest questions: Exactly how fast will the sea rise here before this century’s end?
Charleston rightly deserves credit for recognizing it has a problem — a recognition fueled not only by scientific research but even more so by several years of significant storms and ever-present flooding since 2015. While we also will need national and global action to prevent the worst climate change scenarios and mitigate the impacts of global warming, all we can truly count on is what we do ourselves.
The Charleston (S.C.) Post and Courier
