A recent New York Post (NYP) article, “Scary Map Reveals Major Coastal Cities Rapidly Sinking into Sea”, reports that a study from NASA claims that several major coastal cities are sinking at alarming rates due to a combination of land subsidence and rising sea levels. The NYP specifically mentions sea level problems in New York City, San Francisco, Los Angeles, and other cities, suggesting that their problems are due to a combination of subsidence and rising seas, the latter exacerbated by climate change. The latter point is misleading. Land subsidence is a well-documented problem in some cities, largely driven by local human activities such as groundwater extraction, poor urban planning, and natural geological processes. Subsidence is not due to climate change. However, despite NASA’s claim, long-term sea-level rise trend data does not support claims that seas are rising at historically unusual rates. In fact, seas have been rising at a modest and steady rate for over a century, with no significant acceleration linked to human-caused emissions.
“In many parts of the world, like the reclaimed ground beneath San Francisco, the land is moving down faster than the sea itself is going up,” writes Marin Govorcin, the lead author of the NASA study. who specializes in remote sensing at NASA’s Propulsion Laboratory.”
Commenting on the study, Alexander Handwerger, another researcher at NASA’s Jet Propulsion Laboratory said, “The speed is more than enough to put human life and infrastructure at risk.”
“Accounting for this descent, sea levels — which are on the rise due to climate change — could creep up more than twice as much as previously forecast in Los Angeles and San Francisco in 25 years,” the NYP commented, but the key to the statement and the study itself is land subsidence, not rising seas.
Land subsidence is a localized issue caused primarily by excessive groundwater extraction, infrastructure issues, sediment compaction, and tectonic shifts. Climate change is not a factor in subsidence.
The study, published in Science Advances, cites short term data from satellites to imply that global sea-level rise is accelerating, an implication the NYP fails to question. However, real-world tide gauge data does not support this claim.
Long-term records from tide gauges—considered the gold standard for measuring local sea-level changes—show no evidence of unusual acceleration.
For example, NOAA’s tide gauge data from New York City’s Battery Park station, which has recorded sea levels since 1856, shows a steady rise of about 2.85 millimeters per year—a rate that has remained consistent for more than a century. This aligns closely with global tide gauge records, which show that average sea levels have been rising at a rate of 1-3 millimeters per year since the 1800s. Importantly, this gradual rise is not accelerating, despite increasing CO₂ emissions over the past several decades. See Figure 1 below:
Similarly, tide gauges in San Francisco show a steady sea level rise trend that is even lower than that found in New York City. (See Figure 2, below)
Los Angeles’s rate of sea level rise, shown in Figure 3 below, is lower and slower still.
These three tide gauges from cities mentioned in the NYP article show no short- or long-term acceleration in sea level rise. Globally, in fact, there is little if any acceleration of sea level rise as data presented in Climate at a Glance: Sea Level Rise, demonstrates. Even if recent increases in the rate of rise recorded by some satellites are fully attributable to man-made climate change, it adds only 0.3 inch per decade more to the preexisting historic trend, and is still lower than the rate of rise that has occurred across many periods since the Earth entered its most recent interglacial 18,000 to 12,000 years before present.
Recent modest sea level trends contradict claims that climate change is making sea levels rise at “scary” and accelerated rates. In fact, multiple studies have shown that sea-level rise has remained relatively constant since the end of the Little Ice Age in the 19th century, here, here, here, and here, for example. If greenhouse gas emissions were truly driving an acceleration, we would expect to see a sharp upward trend in tide gauge records over the past 50 years—but we don’t.
A 2022 study highlighted in Climate Realism found that media claims of accelerating sea-level rise are often based on cherry-picked satellite data that fails to align with ground-based tide gauge measurements.
By conflating land subsidence with sea-level rise, all too often media outlets like the NYP mislead the public into believing that climate change is primarily or even solely responsible for coastal flooding threats. This is scientifically inaccurate and distracts from the real issues with subsidence that cities face. By focusing their efforts on the causes of land subsidence, such as ground water extraction issues, and compaction of unstable soil and fill used to add land to city oceanfront, rather than being distracted by the minimal or non-existent role greenhouse gas emissions are having in on sea level rise, policy makers could have far more direct and substantial impact on preventing flooding and losses.
The New York Post got the story half right. Its reporting would have been better had it eschewed any mention of climate change as a factor in the problems facing certain coastal cities.
