SE US: rapid acceleration of sea level rise since 2010
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Started by WxFollower - May 2, 2024, 3:56 p.m.

 At more than a dozen tide gauges spanning from Texas to North Carolina, sea levels are at least 6 inches higher than they were in 2010 — a change similar to what occurred over the previous five decades. 

  In December, Charleston, S.C., saw its fourth-highest water levelsince measurements began in 1899. It was the first time on record that seas had been that high without a hurricane.

 The average sea level at Charleston has risen by 7 inches since 2010, four times the rate of the previous 30 years. 

  Jacksonville, Fla., where seas rose 6 inches in the past 14 years, recently studied its vulnerability.

 Galveston, Tex., has experienced an extraordinary rate of sea level rise — 8 inches in 14 years.

  For this analysis, The Post relied on tide gauge data, which reflects the rise in sea level and sinking of land. Satellite data, which solely measures the height of oceans, was used for global measurements.

  The number of high-tide floods is rapidly increasing in the region, with incidents happening five times as often as they did in 1990, said William Sweet, an oceanographer for the National Oceanic and Atmospheric Administration.

By WxFollower - May 2, 2024, 3:57 p.m.
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 The increase in tidal flooding isn’t just from SLR/CC. Subsidence has also been a major and possibly larger factor in some of these same areas:

 Regions with the highest land subsidence in the United States are mainly located along the East and Gulf Coast

 Analyzing land subsidence rates in large coastal cities, Bekaert and his colleagues found Houston has the fastest peak subsidence rates — about 17 millimeters (0.67 inches) per year from 2014 to 2020 — in the United States. Other research showed parts of Houston lost over 3 meters in elevation in certain areas since 1917.

 Land subsidence in the Houston-Galveston area is largely caused by groundwater withdrawals.

 Parts of New Orleans are also experiencing high rates of sinking, due to both human-induced and natural processes. Research showed that rates are highly variable across the city, ranging from 150 to 500 millimeters (6 to 20 inches) over the past 20 years.

 While Houston and New Orleans are notable subsiding locations, other places in the Gulf also experience high rates. In a large area north of Tampa Bay, subsidence rates have been clocked at up to 6 millimeters (0.24 inches) per year, about twice as much as global sea level rise, from 2015 to 2020 due to groundwater pumping.

By metmike - May 2, 2024, 4:36 p.m.
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Great thread and topic, Larry!

I have covered  a different, crisis level aspect to pumping ground water out that impacts more areas inland but this impact along the coasts which is causing the land to SINK much faster than the oceans are rising is extremely serious.

                The REAL crisis-draining groundwater            

                            Started by metmike - Nov. 2, 2023, 4:31 p.m.    


 That link is paywalled. I'll try to find a link to the study.

By metmike - May 2, 2024, 4:38 p.m.
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Another huge problem that this causes:

Saltwater Intrusion: A Growing Threat to Coastal Agriculture

By metmike - May 2, 2024, 5:30 p.m.
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Sinking US cities increase risk of flooding from rising sea levels

Subsidence linked to extraction of groundwater and natural gas, and weight of buildings pressing into soft ground

Some of this subsidence resulted from pumping out groundwater for water supplies or for natural gas, but New York and other cities are sinking under the sheer weight of their buildings pressing into soft ground.

It is a complex situation, in which there are a number of factors at play. After the great ice sheets melted at the end of the ice age, the ground has also been gradually tilting, with northern areas that were under the ice rising upwards while southern areas that were ice-free tilting downwards.


Post-glacial rebound

A model of present-day mass change due to post-glacial rebound and the reloading of the ocean basins with seawater. Blue and purple areas indicate rising due to the removal of the ice sheets. Yellow and red areas indicate falling as mantle material moved away from these areas in order to supply the rising areas, and because of the collapse of the forebulges around the ice sheets.


What is glacial isostatic adjustment?

Glacial isostatic adjustment is the ongoing movement of land once burdened by ice-age glaciers.


Melting glaciers drove ‘21% of sea level rise’ over past two decades

By metmike - May 2, 2024, 5:51 p.m.
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Climate Change: Ocean Heat Content

Thermal Expansion Causes About One-Third Of Global Sea Level Rise

Increase in sea level variability with ocean warming associated with the nonlinear thermal expansion of seawater


Sea level variability increasingly contributes to coastal flooding and erosion as global sea levels rise, partly due to the thermal expansion of seawater, which accelerates with increasing temperature. Climate model simulations with increasing greenhouse gas emissions suggest that future sea level variability, such as the annual and interannual oscillations that alter local astronomical tidal cycles and contribute to coastal impacts, will also increase in many regions. Here, we present an analysis of the CMIP5 climate model projections of future sea level to show that there is a tendency for a near-global increase in sea level variability with continued warming that is robust across models, regardless of whether ocean temperature variability increases. Specifically, for an upper-ocean warming by 2 °C, which is likely to be reached by the end of this century, sea level variability increases by 4 to 10% globally on seasonal-to-interannual timescales because of the nonlinear thermal expansion of seawater. As the oceans continue to warm, future ocean temperature oscillations will cause increasingly larger buoyancy-related sea level fluctuations that may alter coastal risks.

By 12345 - May 3, 2024, 2:08 a.m.
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By metmike - May 22, 2024, 5:43 p.m.
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With the discussion focusing on the extremely warm tropical Atlantic temperatures, I wonder how much of the sea level increase is the result of thermal expansion?

By WxFollower - June 7, 2024, 9:53 a.m.
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 Yeah, it is from a combo of GW related expansion of the oceans as well as melting glaciers/land ice causing runoff of melted ice into the oceans.

By WxFollower - June 7, 2024, 10:56 a.m.
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  NASA Analysis Sees Spike in 2023 Global Sea Level Due to El Niño

March 21, 2024

 A long-term sea level dataset shows ocean surface heights continuing to rise at faster and faster rates over decades of observations.

Global average sea level rose by about 0.3 inches (0.76 centimeters) from 2022 to 2023, a relatively large jump due mostly to a warming climate and the development of a strong El Niño.

 The data shows that global average sea level has risen a total of about 4 inches (9.4 centimeters) since 1993. The rate of this increase has also accelerated, more than doubling from 0.07 inches (0.18 centimeters) per year in 1993 to the current rate of 0.17 inches (0.42 centimeters) per year.

“Current rates of acceleration mean that we are on track to add another 20 centimeters of global mean sea level by 2050, doubling the amount of change in the next three decades compared to the previous 100 years and increasing the frequency and impacts of floods across the world,”


My comments:

- There looks like an acceleration in the rise since 2011.

- The largest annual rises (based on peak to peak) have been associated with the four strongest El Niño years but also in 2012 (following a two year La Niña) and 1999. 1999 is hard to explain.

- The biggest annual drops (based on peak to peak) were after the three strongest El Niño years. Thus, there’d be a nice drop for the 2024 peak vs 2023 peak assuming the pattern holds.

- Looking at the animation inside the article, the annual peaks have been mostly in Oct although I see a couple in Sep. and a couple in Nov.

- Based on peak to peak rises, 2015 looks like it was pretty close to 2023.

- This article attributes El Niño related rises to more rainfall over the oceans. But I would have thought it would be due to spikes of warmth during El Niño leading to ocean expansion. Any opinions about this?

By metmike - June 7, 2024, 11:32 a.m.
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- This article attributes El Niño related rises to more rainfall over the oceans. But I would have thought it would be due to spikes of warmth during El Niño leading to ocean expansion. Any opinions about this?

Outstanding stuff, Larry, thanks!

I need some time to go over this and respond more(which will be fun) but will give a quick initial response.

1. Agree with your statement above. If the source of the moisture for increased rain is the oceans and it falls back into the oceans, how does this cause an increase. I would think the opposite because most of it comes from the oceans and SOME of it falls over land. For their statement to be right, more comes from land evaporation, exceeding ocean evaporation vs land rainfall and ocean rainfall.

There is no evidence that global soil moisture or large bodies of water on land are being reduced and the oceans are gaining as a result.

Evaporation from the oceans makes ~85-90% of the water in the water cycle.


2. Agree too that the RATE of sea level increase is accelerating slightly. Important factors are melting land ice, thermal expansion and aquifers being drained, resulting in increased runoff to oceans.

3. For sea levels to peak at the end of El Nino's makes sense because of thermal expansion(in that area) and the warmth increasing melting land ice.

4. The time frames for the sea level peak, in the Northern Hemisphere's Fall is interesting.

We know that CO2 levels bottom out/spike down every year at that time for an extremely obvious reason.....photosynthesis. I would think that plants on land would be using up more water at that time. 

We should look at runoff from land to determine if that's a factor. At that time of year, melting of Antarctic land ice is at a minimum, so that wouldn't be it.

5. Recent marine heat waves in NON El Nino regions are contributing to thermal expansion and higher sea levels!!

I haven't even looked at the article so there's probably reasons I'm not thinking of.

It's sometimes good to do this before reading articles. ........BEFORE your mind has a chance to be told what the reasons are for things by the article and is still most open minded.

By WxFollower - June 7, 2024, 12:15 p.m.
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Thanks, Mike. Looking forward to more from you. Meanwhile, I have an amendment based on something I just realized because I missed it the first time:

 There actually is one exception to the autumn peaks, 1998, which technically peaked on Jan 1st as it was slowly dropping from the big late Sep 1997 El Niño related peak. The 1998 autumn peak, which was in mid Sep, wasn’t able to quite reach the Jan 1st level. This can be clearly seen by slowing the animation way down. This slowdown can be done by pausing the animation and then manually controlling the animation via the bottom scroll bar.

  Grand total of the annual peaks:

-22 in Oct

-4 in Sep

-4 in Nov.

-1 in Jan

- There’s also a very minor peak in most years within a month of March. Why?

By metmike - June 7, 2024, 12:54 p.m.
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That’s a well established seasonal pattern so there must be a powerful force causing it.

Maybe that’s when global SSTs peak and this is from seasonal thermal expansion?

I know the peak in the Northern Hemisphere is August But the Sothern Hemisphere has more ocean.

The sun is actually closest to earth in January and farthest in July so that isn’t it. In fact, it’s exactly the opposite of this. Odd.

Maybe it’s related to currents and circulations?

Is the changing amount of water vapor in the atmosphere subject to seasonal highs and lows?

By WxFollower - June 7, 2024, 1:16 p.m.
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Mike said: “Maybe that’s when global SSTs peak and this is from seasonal thermal expansion?”


Hey Mike,

 I think you’re onto something. So, as I mentioned, most years have a very minor secondary peak within a month of March.

  My hypothesis is that this very minor secondary peak is related to the typical  60N to 60S annual global ocean SST peak, which is in/near March as per the image at this link:

By metmike - June 7, 2024, 4 p.m.
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Those are some extremely impressive graphs!

It tells us that something REALLY unusual happened in 2023, that wasn't from greenhouse gas warming that caused global sea surface temperatures, for the first time in history to break MUCH higher than the annual highs, normally set in the Spring(from the Southern Hemisphere being more ocean than the Northern Hemisphere).

If I didn't know anything else, I would strongly suspect this sort of signature is the result of geothermal heat coming out of the oceans bottom.

But the sea surface max's as you indicated come closer (a month or 2) to the annual LOW in global sea surface temperature which look to be in November in most years.

you would think thermal expansion forcing would be highest in the Spring??

I need to go back and read the rest of the article that cutworm sent us.

This guy is really wrong about several assumptions early in my reading, so I postponed reading the rest. 

That doesn't mean he might not have some solid points later on about geothermal/exothermic heat.

                A different hypothesis on global warming                                        4 responses |                                               

                Started by cutworm - June 1, 2024, 10:55 p.m. 



I say this also, as somebody that has always suspected geothermal heat as potentially contributing to more warming than currently assumed..........but without solid proof...........other than huge warm blobs that occur and remain for many months in the same location(surface wind patterns and vertical motions in the ocean can often explain some to much of that).

The rapid onset of La Nina, for instance is coming from the cooler water below in the far eastern tropical Pacific rising to the surface and this will work its way westward the rest of the year in the eastern and central tropical Pacific, apparently without the assistance of geothermal heat. 

By WxFollower - June 14, 2024, 9:26 a.m.
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“The linear trend of SLR along the USSEC in 2010–2022 in observations is ~10.8 mm/year, which is 3–4 times larger than that in 1920–2009 ( ~ 2.6 mm/year).’The authors attribute this to climate change, AMOC changes and internal variability in AMOC and NAO’“ per Jeff Berardelli

By metmike - June 14, 2024, 9:57 a.m.
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Thanks much, Larry!

Causes and multiyear predictability of the rapid acceleration of U.S. Southeast Sea level rise after 2010

The rate of sea level rise (SLR) along the Southeast Coast of the U.S. increased significantly after 2010. While anthropogenic radiative forcing causes an acceleration of global mean SLR, regional changes in the rate of SLR are strongly influenced by internal variability. Here we use observations and climate models to show that the rapid increase in the rate of SLR along the U.S. Southeast Coast after 2010 is due in part to multidecadal buoyancy-driven Atlantic meridional overturning circulation (AMOC) variations, along with heat transport convergence from wind-driven ocean circulation changes. We show that an initialized decadal prediction system can provide skillful regional SLR predictions induced by AMOC variations 5 years in advance, while wind-driven sea level variations are predictable 2 years in advance. Our results suggest that the rate of coastal SLR and its associated flooding risk along the U.S. southeastern seaboard are potentially predictable on multiyear timescales.