If it floods ten or fifteen times a month, a business can't keep operating
Every 18.6 years, the moon's orbit shifts in a way that amplifies the tides — a quiet celestial rhythm that has shaped coastlines long before human memory. NASA now warns that when this wobble returns in the mid-2030s, it will meet a coastline already strained by a decade more of climate-driven sea level rise, producing a new era of chronic flooding across most of the American shore. This is not the story of a single storm, but of two slow forces arriving together — one written in the moon's ancient motion, the other in the warming of the seas.
- NASA's Sea Level Change Team has mapped a precise collision point: the moon's next tide-amplifying phase in the mid-2030s will coincide with another decade of rising seas, overwhelming coastal defenses that were never built for this.
- The threat is not a wall of water but a relentless drip — high-tide floods arriving ten to fifteen times a month, clustering for days at a time, turning ordinary streets into recurring obstacles.
- Unlike hurricanes, these nuisance floods corrode infrastructure slowly, close roads without warning, and make it impossible for workers to reach jobs or businesses to stay open — the damage accumulates quietly until it becomes irreversible.
- Alaska and parts of the northern coast will be spared by geological uplift, but Hawaii, Guam, and most US coastlines face a future where the ordinary tide is no longer compatible with ordinary life.
- Coastal planners now have something rare — a calendar of consequence — and researchers are urging cities to act now on drainage systems, elevated infrastructure, and managed retreat before the two forces converge.
The moon has a rhythm most of us never notice. Every 18.6 years, its orbit wobbles in a way that pushes tides higher and pulls them lower. In the mid-2030s, that wobble will return — and this time, NASA warns, it will arrive alongside something far more consequential: seas that will have spent another decade rising due to climate change.
Researchers at NASA's Sea Level Change Science Team published their findings in Nature Climate Change, modeling every force that shapes coastal flooding — lunar gravity, solar position, ocean currents, weather patterns — and projecting them forward to 2080. Their conclusion is stark: most of the American coastline, along with Hawaii and Guam, will be struck by a surge of high-tide flooding in the 2030s. Only Alaska and parts of the northern coast, slowly rising through geological processes, will be spared.
These are not hurricane floods. They happen on ordinary days when the tide simply rises too high and spills into streets, parking lots, and storm drains. NOAA has documented their toll: corroded infrastructure, closed roads, contaminated water systems, and businesses unable to operate. What makes them dangerous is not their size but their frequency — some coastal cities could see them ten to fifteen times a month, clustering in waves that last for weeks.
Lead author Phil Thompson of the University of Hawaii put it plainly: a parking lot that floods that often cannot support a business. People lose their livelihoods not to a single catastrophe but to tides that have become incompatible with daily life. The accumulated effect, he said, is what transforms a nuisance into a crisis.
For planners, the study offers something rare: precision about when the worst will arrive. NASA's Ben Hamlington stressed that knowing which months will cluster the most severe flooding is crucial for cities deciding where to invest in drainage, elevated infrastructure, and managed retreat. The moon's wobble is already in its amplifying phase, but sea levels have not yet risen enough for most coasts to feel it. By the time the cycle returns in the 2030s, that margin will be gone — and the two forces will arrive together.
The moon has a rhythm that most of us never think about. Every 18.6 years, its orbit wobbles in a way that amplifies the tides on Earth—pushing them higher, pulling them lower, with consequences that ripple across our coastlines. In the middle of the next decade, that wobble will return. And this time, NASA warns, it will collide with something far more consequential: the steady rise of the seas caused by climate change.
Researchers at NASA's Sea Level Change Science Team have published a new study in Nature Climate Change that maps this collision with precision. They looked at every known force that shapes coastal flooding—the moon's gravity, the sun's position, ocean currents, weather patterns like El Niño—and projected the results forward to 2080. What they found is stark: when the moon's tide-amplifying phase arrives in the mid-2030s, most of the American coastline will be hit by a surge of what scientists call high-tide floods, or nuisance floods. Hawaii and Guam will face them too. Only the northern coasts, including Alaska, will be spared, because those regions are slowly rising due to geological processes that work on timescales of thousands of years.
These floods are not the dramatic wall of water that hurricanes bring. They happen on ordinary days, when the tide simply rises higher than usual and spills into streets, parking lots, and neighborhoods. They overwhelm storm drains. They close roads. They seep into basements and cesspools, turning public health into a crisis. The National Oceanic and Atmospheric Administration has documented their effects: infrastructure corroded by repeated saltwater exposure, businesses unable to operate, workers unable to reach their jobs. What makes them dangerous is not their individual severity but their frequency and their clustering. By the 2030s, some coastal cities could see these floods ten to fifteen times a month. They may come in waves—every day or two for weeks at a time, depending on where the moon, sun, and Earth align.
Phil Thompson, an assistant professor at the University of Hawaii and the lead author of the study, put it plainly: if your parking lot floods that often, your business cannot survive. People lose their livelihoods not because of a single catastrophic storm but because the ordinary tides have become incompatible with ordinary life. The accumulated effect, he said, is what matters. A single flood is a nuisance. Ten floods a month is a transformation.
For coastal planners, the study offers something they have lacked: precision about when the crisis will arrive. Most planning efforts focus on preparing for extreme weather—the hurricanes, the nor'easters, the once-in-a-century storms. But chronic flooding operates on a different timeline and requires a different kind of preparation. Ben Hamlington, who leads NASA's Sea Level Change Team, emphasized that knowing when these events will cluster—understanding that you might face more severe flooding in the second half of a year than the first, or that a particular month will be especially bad—is crucial information for cities trying to decide where to invest in drainage systems, elevated infrastructure, and managed retreat.
The timing is the crux of it. The moon is currently in the tide-amplifying part of its wobble, but most American coastlines have not yet experienced enough sea-level rise to feel the effects. By the time the wobble returns to its amplifying phase in the mid-2030s, global sea levels will have risen for another decade. The two forces will arrive together. NASA administrator Bill Nelson framed it as a convergence: the moon's gravitational pull, rising seas, and climate change will exacerbate coastal flooding across the world. The study is the first to account for all these forces simultaneously, mapping them against NOAA's sea-level rise scenarios and the thresholds at which flooding begins. What emerges is not a prediction of catastrophe but a calendar of consequence—a decade away, written in the moon's ancient rhythm and the warming of the seas.
Notable Quotes
The combination of the moon's gravitational pull, rising sea levels, and climate change will continue to exacerbate coastal flooding on our coastlines and across the world.— NASA Administrator Bill Nelson
If it floods 10 or 15 times a month, a business can't keep operating with its parking lot underwater. People lose their jobs because they can't get to work.— Phil Thompson, University of Hawaii, lead author of the study
The Hearth Conversation Another angle on the story
Why does the moon's wobble matter if we're already dealing with rising seas from climate change?
Because timing is everything. The wobble amplifies tides on its own cycle. When that amplification arrives in the 2030s, it will hit coastlines that have already risen by another decade of climate-driven sea level. The two forces won't cancel each other out—they'll compound.
So it's not just higher tides. It's higher tides happening more often.
Exactly. And happening in clusters. Some months you might see flooding every day or two. A business can't operate with its parking lot underwater that frequently. People can't get to work. The infrastructure starts to fail from repeated saltwater exposure.
Why are northern coastlines like Alaska spared?
They're rising due to geological processes—the land itself is moving upward. It's been happening for thousands of years. By the 2030s, that upward movement will still outpace the sea level rise in those regions.
This study seems to be saying planners need to think differently about flooding.
Yes. Most planning focuses on extreme events—hurricanes, storms. But chronic flooding is different. It's not dramatic, so it's easy to dismiss. But if it happens ten times a month, it becomes a permanent condition, not a disaster.
When does this actually start affecting people?
The wobble enters its amplifying phase in the mid-2030s. That's when the effects will become visible and severe. But the planning needs to happen now, because infrastructure takes time to build or relocate.
Is there anything that can stop it?
No. The wobble is astronomical—it's baked into the moon's orbit. What we can do is prepare: better drainage, elevated infrastructure, managed retreat from the most vulnerable areas. But we have to know it's coming, and we have to plan for it.