Rising sea levels could swamp the US coastline by 2050, NASA predicts

Jason Elam wades through flood waters around his home after Hurricane Nicole blew ashore on Nov. 10, 2022 in Daytona Beach, Florida.
Jason Elam wades through flood waters around his home after Hurricane Nicole blew ashore on Nov. 10, 2022 in Daytona Beach, Florida. (Image credit: Joe Raedle/Getty Images)

Sea levels are likely rising faster than previously thought, meaning low-lying coastal cities in the U.S. could flood far more regularly in the coming decades, a NASA study has revealed.

According to the study, which analyzed three decades of satellite observations, by 2050, sea levels along the coastlines of the contiguous U.S. could rise as much as 12 inches (30 centimeters) above current waterlines, the research team said in a statement (opens in new tab). The Gulf Coast and Southeast are expected to be most severely impacted, and will likely experience increased storm and tidal flooding in the near future, according to the study, published Oct. 6 in the journal Communications Earth & Environment (opens in new tab).

The findings support the "higher-range" scenarios laid out in February in the multi-agency Sea Level Rise Technical Report (opens in new tab). The report suggested that "significant sea level rise" is liable to hit U.S. coasts within the next 30 years, predicting 10 to 14 inches (25 to 35 cm) of rise on average for the East Coast; 14 to 18 inches (35 to 45 cm) for the Gulf Coast; and 4 to 8 inches (10 to 20 cm) for the West Coast."

NASA's study built on methods used in the earlier multi-agency report, and was headed by a team of researchers and scientists based at the Jet Propulsion Laboratory (opens in new tab) in California, which is dedicated to both exploring the deepest recesses of space, and also using satellites to "advance understanding" of Earth.

NASA's research harnessed satellite altimeter measurements of sea surface height and then correlated them with National Oceanic and Atmospheric Administration (opens in new tab) (NOAA) tide gauge records dating back over 100 years. As a result, NASA can confidently state that its satellite readings are not anomalous, and are fully supported by findings on the ground.

Related: Climate summit agrees to 'historic' loss-and-damage fund — but misses warming goals

In this 2021 map of Earth, we see sea levels measured by the Sentinel-6 Michael Freilich satellite. Regions with red areas have higher than normal sea levels, while blue indicates have below normal. (Image credit: NASA Earth Observatory)

While the new study's findings are undoubtedly cause for concern, Jonathan Overpeck (opens in new tab), an interdisciplinary climate scientist at the University of Michigan who was not involved with the research, suggested that the projections have by no means come out of the blue. 

"NASA's findings appear robust and they are not surprising. We know that sea level rise is accelerating and we know why," he told Live Science in an email. "More and more polar ice is melting, and this is on top of the oceans expanding as they warm. Clearly, the sea level rise will get worse as long as we let climate change continue."

This viewpoint is shared by David Holland (opens in new tab), a physical climate scientist and professor of mathematics at New York University who was not involved with the study. "The quality of the satellite data is excellent, and so the findings are reliable," Holland told Live Science in an email. "The study shows that the global ocean is rising, and more than that, the rise is accelerating. The projected rise for the Gulf coast of about 1 foot by 2050 is enormous. This can make hurricane-related storm surges even worse than is presently the case."

In this illustration, the Sentinel-6 Michael Freilich satellite measures the height of the oceans from space. (Image credit: NASA/JPL-Caltech)

Other factors may also contribute to rising sea levels along the U.S. coastline. The study indicated that the issues associated with rising sea levels could be "amplified by natural variabilities on Earth," such as the effects of El Niño and La Niña by the mid-2030s, with every U.S. coast set to encounter "more intense high-tide floods due to a wobble in the moon's orbit that occurs every 18.6 years," according to the statement.

The effects of El Niño — the warming of surface temperatures in the Pacific Ocean near South America which can lead to increased rainfall — and La Niña — the cooling of surface ocean waters in the Pacific — can make accurately forecasting sea level rise a challenge, and can potentially skew readings. Ben Hamlington, leader of the NASA Sea Level Change Team, noted that natural events and phenomena will always need to be taken into consideration, and said that all forecasts will inevitably be refined as satellites gather data over time.

Despite the study's bleak findings, some experts are hopeful that impactful, high-profile research such as this will compel decision-makers to focus on addressing the ongoing climate crisis and encourage the public to demand effective measures be introduced.

"It is impossible to ignore. I think this [increased flooding] is catalyzing action, as many coastal communities are discussing these issues and how they respond," said Robert Nicholls (opens in new tab), director of the Tyndall Centre for Climate Change Research in the U.K., who was not involved with the study. "We have the means to deal with this challenge in terms of mitigation to stabilize global temperatures and slow — but not completely stop — sea level rise, which, unfortunately, will continue for centuries due to the warming we have already experienced."

Ultimately, humanity will need to adapt as climate change alters our planet's oceans and seas. 

"This could involve retreat in some places, raising land in other places, and defenses elsewhere," Nicholls told Live Science. "There is no one solution that will be applicable everywhere. If we follow this path the future is manageable. Equally, if governments and society ignore these issues, the future will be a real mess."

Joe Phelan
Live Science Contributor

Joe Phelan is a journalist based in London. His work has appeared in VICE, National Geographic, World Soccer and The Blizzard, and has been a guest on Times Radio. He is drawn to the weird, wonderful and under examined, as well as anything related to life in the Arctic Circle. He holds a bachelor's degree in journalism from the University of Chester. 

  • Mous
    we need to select some random politician that we don't like but who has a lot of connections and appoint him to be in charge of keeping the temp rise below 1.5. Add a bilion dollar bonus if he succeeds and a cell in guantanamo if he doesn't.
    Reply
  • kunling
    Why are the biggest polluters, China and India, never addressed in any articles involving global warming, yeah, I said it? Instead, the US and other developed countries are expected to pay/contribute to the scam. uhh, redistribute the wealth.
    Reply
  • SouthSideRich
    Hello!
    Do we all agree that sea levels have been rising for thousands of years and are currently rising about 3.3 millimeters per year?

    "From what is observed in the figure above, sea level rise rates appear to have been relatively low during initiation of rise (i.e., from 20,000 to approximately 15,000 years ago), at which point a significant increase in sea level rise rates (Meltwater Pulse 1A), and several others ensued. Three rapid increases in rise rates ("pulses") are noted here so that the majority of the 100 meters of sea level rise occurred from 14,000 to approximately 8,000 years ago, or 90 meters in roughly 6,000 years. This yields a sea level rise rate of 0.015 meters per year or 1.5 centimeters per year or 15 mm per year.

    This is an incredibly fast rate that is tied to the decay of large ice sheets including both the Eurasian and Laurentide Ice Sheets. The Laurentide Ice Sheet on North America had mostly retreated from North America by 6,000 years ago leaving behind only the alpine ice sheets.

    Holocene Sea Level curve showing the most recent period of rise and warming. Some of these data suggest that sea levels approached modern around 6,000 years ago, but may have actually exceeded modern sea levels in some regions (i.e., Malacca), but, on average, sea levels have been relatively slow to rise and have been fairly stable for at least the last few thousand years."

    Credit: Image created by Robert A. Rohde / Global Warming Art
    https://www.e-education.psu.edu/earth107/node/1506
    Reply
  • Broadlands
    "Despite the study's bleak findings, some experts are hopeful that impactful, high-profile research such as this will compel decision-makers to focus on addressing the ongoing climate crisis and encourage the public to demand effective measures be introduced."
    It would be useful if those experts who write such statements would tell us what some "effective measures" are that might work. Obviously, lowering our emissions takes no CO2 out of the atmosphere and carbon capture and geological storage is energy intensive and takes very little out.
    Reply
  • SouthSideRich
    Broadlands said:
    "Despite the study's bleak findings, some experts are hopeful that impactful, high-profile research such as this will compel decision-makers to focus on addressing the ongoing climate crisis and encourage the public to demand effective measures be introduced."
    It would be useful if those experts who write such statements would tell us what some "effective measures" are that might work. Obviously, lowering our emissions takes no CO2 out of the atmosphere and carbon capture and geological storage is energy intensive and takes very little out.
    Broadlands said:
    "Despite the study's bleak findings, some experts are hopeful that impactful, high-profile research such as this will compel decision-makers to focus on addressing the ongoing climate crisis and encourage the public to demand effective measures be introduced."
    It would be useful if those experts who write such statements would tell us what some "effective measures" are that might work. Obviously, lowering our emissions takes no CO2 out of the atmosphere and carbon capture and geological storage is energy intensive and takes very little out.
    Depends on what you are wanting to accomplish. If you want less CO2 in the air then promote regenerative farming practices; however the CO2 in the air is actually at historic lows and the other plant life might suffocate with even less of it.
    If you want to drop the sea levels then we need to cool down our atmosphere; which is definitely not good for plant-life.
    We require these plants to thrive so I suggest that we simply enjoy this brief warm period while it lasts because it's those colder periods that will give humans much more concern.
    (There was thousands of feet of ice on top of where millions of people now live about 10,000 years ago and that ice will come back.)
    In retrospect, this is a great time to live and I'm Lovingly Grateful.
    What do we really want to beautifully create next?
    Reply
  • Cvelo
    Mous said:
    we need to select some random politician that we don't like but who has a lot of connections and appoint him to be in charge of keeping the temp rise below 1.5. Add a bilion dollar bonus if he succeeds and a cell in guantanamo if he doesn't.
    There is no way the temp rise will stay under 1.5c. We are 6 years away from that now. It will be ~+2c by 2050. The question is will it go past +2c? https://climateclock.world/
    Reply
  • Cvelo
    kunling said:
    Why are the biggest polluters, China and India, never addressed in any articles involving global warming, yeah, I said it? Instead, the US and other developed countries are expected to pay/contribute to the scam. uhh, redistribute the wealth.
    China is apparently substantially ahead of the USA in addressing carbon emissions. Consider that a reason. India, they are doing more than the USA too. Big tax increase on fuel and moving to renewables. "redistribute the wealth", inaccurate but I get what is implied. It is like this. You hate paying for a fire department and want to stop but your own house is on fire. https://www.weforum.org/agenda/2015/07/6-ways-india-is-tackling-climate-change/
    Reply
  • Cvelo
    Well, blatant lying pretty much makes you look like a jackass. That's what happens when you quote idiot conspiracy theory sites.
    CO2 rise by humans is traceable back almost 500 years. The last 50 years have tracked much as climate scientists predicted. I have a scientific review of dozens of deniers falling flat on their faces. Just like you. Stop trying (and failing) to waste people time.
    https://www.science.org/content/article/even-50-year-old-climate-models-correctly-predicted-global-warminghttps://www.axios.com/2022/10/06/climate-change-summer-droughts
    Reply
  • SouthSideRich
    Cvelo said:
    Well, blatant lying pretty much makes you look like a jackass. That's what happens when you quote idiot conspiracy theory sites.
    CO2 rise by humans is traceable back almost 500 years. The last 50 years have tracked much as climate scientists predicted. I have a scientific review of dozens of deniers falling flat on their faces. Just like you. Stop trying (and failing) to waste people time.
    https://www.science.org/content/article/even-50-year-old-climate-models-correctly-predicted-global-warminghttps://www.axios.com/2022/10/06/climate-change-summer-droughts
    There's no need to stifle conversation nor to use pejoratives while discussing ideas. Science is created from healthy debate.
    I request that every one to share their perspectives so that others can possibly see something anew and we all advance from there.
    Thank You Gentle Human Beings.
    Reply
  • bvysfufeugo xqf
    hi there yes i agree that sea level are rising
    Reply