A rising ocean is already causing coastal flooding in some areas on the Eastern Seaboard during high “king” tides — even without the storm systems made more dangerous by a warmer Atlantic. As if the swirl of variables in the climate crisis weren’t complicated enough, soon the moon will have something to say about it too.
According to a study released this week in the journal Nature Climate Change, by the NASA Sea Level Change Team at the University of Hawaii, a moon “wobble” will cause “a decade of dramatic increases in flood numbers” beginning in the mid-2030s. Over its 18.6-year orbit around Earth, the moon amplifies and suppresses the tide depending on where it is in its route. At the moment, we’re in an amplification cycle, though we are not experiencing extreme high tides because the global mean sea level has risen only about eight to nine inches, according to the National Oceanic and Atmospheric Institute. But next time around, higher seas and higher tides will coincide for more frequent and more significant tidal flooding.
According to NASA administrator Bill Nelson, the wobble will make “low-lying areas near sea level … increasingly at risk and suffering due to the increased flooding, and it will only get worse.” The NASA team that published the study estimates that tidal flooding will occur four times as often as in 2019, when the National Oceanic and Atmospheric Administration reported over 600 sunny-day flooding incidents. NASA noted that only far-northern coastlines, including those in Alaska, will be spared the increased flooding, as “these land areas are rising due to long-term geological processes.”
As the study shows, our understanding of the climate crisis — let alone any significant action — will become increasingly complex as the years pass. This isn’t necessarily a new lesson: Earlier this year, a study in Nature found that the practice of trawling on the seabed to catch fish releases as much carbon as the global aviation industry does. But the moon’s wobble reminds us that there are extraterrestrial factors at work as well.