Sea level rise?

eohrnberger · Sep 16, 2016

Glen Contrarian said:
Being on the surface in the form of plant or animal mass is one thing. Being exhausted into our atmosphere in gaseous form is another thing altogether.

Funny, I thought that plants pull the carbon for their biomass from the atmosphere.

eohrnberger · Sep 16, 2016

iguanaman said:
LOL Now you are just being a clown. More likely that until the plants sequestered all that carbon, higher animal life could not develop because of the excess heat. Now we are releasing what took millions of years to remove in a few hundred...What could go wrong.....

The Last Time CO2 Was This High, Humans Didn't Exist | Climate Central

No, higher, more complex life already existed before the Carboniferous period.

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, at 358.9 ± 0.4 million years ago, to the beginning of the Permian Period, at 298.9 ± 0.15 Mya.

Mean atmospheric O
2 content over period duration c. 32.5 vol %[1][2]
(163 % of modern level)
Mean atmospheric CO
2 content over period duration c. 800 ppm[3][4]
(3 times pre-industrial level)
Mean surface temperature over period duration c. 14 °C[5][6]
(0 °C above modern level)
Sea level (above present day) Falling from 120 m to present-day level throughout the Mississippian, then rising steadily to about 80 m at end of period[7]

https://en.wikipedia.org/wiki/Carboniferous

The Permian is a geologic period and system which extends from 298.9 to 252.17 million years ago.[8] It is the last period of the Paleozoic, following the Carboniferous and preceding the Triassic of the Mesozoic.

Mean atmospheric O
2 content over period duration c. 23 vol %[1][2]
(115 % of modern level)
Mean atmospheric CO
2 content over period duration c. 900 ppm[3][4]
(3 times pre-industrial level)
Mean surface temperature over period duration c. 16 °C[5][6]
(2 °C above modern level)
Sea level (above present day) Relatively constant at 60 m (200 ft) in early Permian; plummeting during the middle Permian to a constant −20 m (−66 ft) in the late Permian.[7]

. . .

https://en.wikipedia.org/wiki/Permian#Life

Point being that high forms, more complex forms, of life already existed prior to the Carboniferous period, as show in the reference to the previous period, the Permian period. They were also present in the Triassic before Permian, and the Jurassic before that and the Cretaceous before that. Hell, mammals were even present in the period previous to that, the Paleogene period.

The Paleogene (pronunciation: /ˈpæliːədʒiːn/ or /ˈpeɪliːədʒiːn/; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that began 66 million years ago and ended 23.03 million years ago and comprises the first part of the Cenozoic Era.[9] Lasting 43 million years, the Paleogene is most notable as being the time in which mammals evolved from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cretaceous Period.[10]

Mean atmospheric O
2 content over period duration c. 26 vol %[1][2]
(130 % of modern level)
Mean atmospheric CO
2 content over period duration c. 500 ppm[3][4]
(2 times pre-industrial level)
Mean surface temperature over period duration c. 18 °C[5][6]
(4 °C above modern level)

https://en.wikipedia.org/wiki/Paleogene#Flora_and_fauna

I think you may need to familiarize yourself with the subject matter a bit more before making such bold, and incorrect, statements.

jmotivator · Sep 16, 2016

longview said:
The Sea level has been raising for thousands of years, the rate has not changed much in the last few hundred.

And the islands in the pacific have been shown to be affected by the El Nino ocean swell as increased trade winds pile water east from the Indian ocean.

longview · Sep 16, 2016

Glen Contrarian said:
Do you even know how to read that map???? Apparently not!

There are FAR more measurements of rising sea levels than falling sea levels on that map!!!! If the sea level weren't rising appreciably, then you'd see a roughly equal amount...but the amount is NOWHERE near equal, as that map makes PAINFULLY clear!!!!

What's more, the overwhelming majority of the rising measurements are from 0-2 feet/century over most of the map...and the meaning of that should be crystal clear - that's a POSITIVE sign of relatively equal amounts of sea level rise over much of the planet. YES, geology plays a part...which accounts for the relatively few measurements that show falling sea levels...

...in other words, almost ANY measurement on that map showing something other than the 0-2 ft/century rise is due to geologic effects. All other measurements are clearly due to the sea level itself rising.

Where did I say the sea level was not raising overall? Cite the post number?
What did I say,

The sea levels have been raising and will continue to rise,

The question is, Is there a measurable acceleration to the sea level rise, related to AGW,
So far the answer appears to be NO!

longview · Sep 16, 2016

Tim the plumber said:
As I have pointed out the day length data says it has not been changing at all.

Given that looking out of the window on a stormy night to get the high tide level for navigation purposes in 1900 will get you a different number to the hyper accurate pressure sensors we use tody why would you think the historic data is accurate?

I understand what you are saying, but tide gauges have been about 1 mm of accuracy for about 200 years.
They have gotten better. I think it is funny when people compare satellites with their 30 mm of accuracy
to the gauges at better than a 1 mm of accuracy.

longview · Sep 16, 2016

jmotivator said:
And the islands in the pacific have been shown to be affected by the El Nino ocean swell as increased trade winds pile water east from the Indian ocean.

In watching the tide for fishing, wind is every bit as much a factor as the tide itself.

joG · Sep 16, 2016

longview said:
So 4 new papers out saying that an AGW signal cannot be detected in sea level raise.

Four Studies Find ?No Observable Sea-Level Effect? From Man-Made Global Warming

Watching sea levels rise is much like watching grass grow on a windy day.

KLATTU · Sep 16, 2016

Glen Contrarian said:
Yeah And the small island nations that are slowly getting flooded out of existence because of the rise of the sea level, that's magic, too!

Some poor people are literally drowning all because energy hogs like Obama, Gore, Clinton,Tom Friedman, Leo Di Caprio and George Clloney want to live in mansions and jet around the world. Hey, me first ,right?

longview · Sep 16, 2016

joG said:
Watching sea levels rise is much like watching grass grow on a windy day.

I think the grass grows much faster.:mrgreen:

Tim the plumber · Sep 16, 2016

longview said:
I understand what you are saying, but tide gauges have been about 1 mm of accuracy for about 200 years.
They have gotten better. I think it is funny when people compare satellites with their 30 mm of accuracy
to the gauges at better than a 1 mm of accuracy.

You recon.

How did we measure sea level 200 years ago on a stormy night when no ship was going to try to make it into the harbour and it was dangerous and very unpleasant to go onto the quay side?

longview · Sep 16, 2016

Tim the plumber said:
You recon.

How did we measure sea level 200 years ago on a stormy night when no ship was going to try to make it into the harbour and it was dangerous and very unpleasant to go onto the quay side?

Fairly early on, they developed something called a stilling well (some say stilling pool)
http://refmar.shom.fr/documentation/instrumentation/puits-de-tranquillisation
I believe the design from Brest France is from the early 1800's, but they are basically
low pass filters, filtering out the high frequency waves, and observing the sea level/tide levels (much lower frequency).

Lord of Planar · Sep 16, 2016

longview said:
I understand what you are saying, but tide gauges have been about 1 mm of accuracy for about 200 years.
They have gotten better. I think it is funny when people compare satellites with their 30 mm of accuracy
to the gauges at better than a 1 mm of accuracy.

But real, factual data cannot be properly "corrected!"

Glen Contrarian · Sep 16, 2016

KLATTU said:
Some poor people are literally drowning all because energy hogs like Obama, Gore, Clinton,Tom Friedman, Leo Di Caprio and George Clloney want to live in mansions and jet around the world. Hey, me first ,right?

Compared to even one small city's worth of CO2 emissions, all their emissions put together are very small potatoes indeed.

Yet another example of a conservative pointing at the very minuscule and somehow thinking it's the same as the great big freaking mountain: "Why should I do anything about that mountain of a problem when there's this grain of sand that's just as much of a problem!!!!"

Tim the plumber · Sep 16, 2016

longview said:
Fairly early on, they developed something called a stilling well (some say stilling pool)
http://refmar.shom.fr/documentation/instrumentation/puits-de-tranquillisation
I believe the design from Brest France is from the early 1800's, but they are basically
low pass filters, filtering out the high frequency waves, and observing the sea level/tide levels (much lower frequency).

Yes but still in 1820 the harbour master was an ex-navy man who was an alcoholic (he was ex-navy man thus almost had to be if he was British) and cared about how navigable the sea was not any sort of hyper accurate recording of the depth of the ocean.

Day length does not suffer from these problems and shows no such increase in sea level.

Glen Contrarian · Sep 16, 2016

longview said:
Where did I say the sea level was not raising overall? Cite the post number?
What did I say,

The question is, Is there a measurable acceleration to the sea level rise, related to AGW,
So far the answer appears to be NO!

Ah. So the seas are rising because of...magic? If it were because the land was sinking, you'd see degrees of rising and falling all over the place...

...but what the map clearly shows is that over most of the planet, with relatively very few exceptions, the seas are rising to relatively equal degrees...and that canNOT be explained by subsidence of the land. Such a claim would require that most of the land on the planet is sinking at the same time to roughly the same degree...and that's a patently silly proposition.

The only plausible answer is that there is a lot more water than there was before...and we already know that the polar ice cap is shrinking to the point that the northwest passage is now navigable, and Greenland lost a trillion tons of ice in just four years.

THAT, sir, means that there's a heck of a lot more water in our oceans. Do you really think that that much more water in our oceans wouldn't result in the rising of our sea levels?

Lord of Planar · Sep 16, 2016

Glen Contrarian said:
THAT, sir, means that there's a heck of a lot more water in our oceans. Do you really think that that much more water in our oceans wouldn't result in the rising of our sea levels?

What about thermal expansion?

Are you discounting it entirely?

Glen Contrarian · Sep 16, 2016

eohrnberger said:
Funny, I thought that plants pull the carbon for their biomass from the atmosphere.

And there should be a balance because of that, shouldn't there? Problem is, there's something upsetting that balance, something that nature has NEVER had to adjust for at any time in our planet's history: worldwide human civilization pumping gigatonnes of CO2 into our atmosphere from sources that nature never faced before.

What's more, our planet's biomass is less than it once was, thanks to deforestation wherever humans have settled. America's forests used to be almost as ubiquitous as are those in Canada...but not now. Same thing's going on in Africa, Asia, and especially in the Amazon.

Is it really so unthinkable that worldwide human civilization pumping literal gigatonnes of CO2 into our atmosphere every single year would affect the chemical makeup of our atmosphere, and so affect our climate? Is it really so heretical to you?

Glen Contrarian · Sep 16, 2016

Tim the plumber said:
Pacific island are all sinking slowly into the ocean bed. Well the little volcanic ones. This is what happens.

The Life and Death of a Volcanic Island

You'd have a point if it were only one or two such volcanic islands...but it's not. It's a problem faced by ALL the very-low-elevation islands around the world.

By the way, Greenland lost a freaking TRILLION tons of ice in the past four years. If that isn't one of the prime sources of the rising sea level, then where did all that water go, hm?

eohrnberger · Sep 16, 2016

Glen Contrarian said:
And there should be a balance because of that, shouldn't there? Problem is, there's something upsetting that balance, something that nature has NEVER had to adjust for at any time in our planet's history: worldwide human civilization pumping gigatonnes of CO2 into our atmosphere from sources that nature never faced before.

What's more, our planet's biomass is less than it once was, thanks to deforestation wherever humans have settled. America's forests used to be almost as ubiquitous as are those in Canada...but not now. Same thing's going on in Africa, Asia, and especially in the Amazon.

Is it really so unthinkable that worldwide human civilization pumping literal gigatonnes of CO2 into our atmosphere every single year would affect the chemical makeup of our atmosphere, and so affect our climate? Is it really so heretical to you?

Actually, the point I was making that no one has responded to was that during the course of the Earth's long history, there were times, extended millions of years in fact, where there were higher levels of CO2 in the atmosphere, and it didn't cause any problems for life. It in fact flourished.

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, at 358.9 ± 0.4 million years ago, to the beginning of the Permian Period, at 298.9 ± 0.15 Mya.

Mean atmospheric O2 content over period duration
c. 32.5 vol %[1][2]
(163 % of modern level)
Mean atmospheric CO2 content over period duration
c. 800 ppm[3][4]
(3 times pre-industrial level)
Mean surface temperature over period duration c. 14 °C[5][6]
(0 °C above modern level)
Sea level (above present day) Falling from 120 m to present-day level throughout the Mississippian, then rising steadily to about 80 m at end of period[7]

https://en.wikipedia.org/wiki/Carboniferous

The Permian is a geologic period and system which extends from 298.9 to 252.17 million years ago.[8] It is the last period of the Paleozoic, following the Carboniferous and preceding the Triassic of the Mesozoic.

Mean atmospheric O2 content over period duration
c. 23 vol %[1][2]
(115 % of modern level)
Mean atmospheric CO2 content over period duration
c. 900 ppm[3][4]
(3 times pre-industrial level)

Mean surface temperature over period duration c. 16 °C[5][6]
(2 °C above modern level)
Sea level (above present day) Relatively constant at 60 m (200 ft) in early Permian; plummeting during the middle Permian to a constant −20 m (−66 ft) in the late Permian.[7]

https://en.wikipedia.org/wiki/Permian#Life

The Paleogene (pronunciation: /ˈpæliːədʒiːn/ or /ˈpeɪliːədʒiːn/; also spelled Palaeogene or Palæogene; informally Lower Tertiary) is a geologic period and system that began 66 million years ago and ended 23.03 million years ago and comprises the first part of the Cenozoic Era.[9] Lasting 43 million years, the Paleogene is most notable as being the time in which mammals evolved from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding Cretaceous Period.[10]

Mean atmospheric O2 content over period duration
c. 26 vol %[1][2]
(130 % of modern level)
Mean atmospheric CO2 content over period duration
c. 500 ppm[3][4]
(2 times pre-industrial level)
Mean surface temperature over period duration c. 18 °C[5][6]
(4 °C above modern level)

https://en.wikipedia.org/wiki/Paleogene#Flora_and_fauna

The question I was asking was how these previous 3 times pre-industrial levels of CO2 compared to present day levels of CO2.

Glen Contrarian · Sep 16, 2016

Lord of Planar said:
What about thermal expansion?

Are you discounting it entirely?

And why would there be thermal expansion? That would only occur if the oceans are warming, right? Right. And according to most of the AGW-denial crowd, that ain't happening.

In other words, what you just did was use one of the facts proving that the planet is warming to try to disprove the fact that the planet is warming. :doh

Either way, has it occurred to you that BOTH the gigatonnes of glacier melt being added to our oceans every year AND the thermal expansion of seawater are combining to account for the rise of the sea levels over much of the world? It's NOT an either-or - it's BOTH.

iguanaman · Sep 16, 2016

eohrnberger said:
Actually, the point I was making that no one has responded to was that during the course of the Earth's long history, there were times, extended millions of years in fact, where there were higher levels of CO2 in the atmosphere, and it didn't cause any problems for life. It in fact flourished.

The question I was asking was how these previous 3 times pre-industrial levels of CO2 compared to present day levels of CO2.

Except that most of the "flourishing life" from those times is now extinct and humans along with most living species have never lived in such a warm environment. The fact that this escapes you is telling.

Even today, heatwaves can kill tens of thousands of people. In France alone, more than 14,800 people died of heat stroke in 2003. Hurricanes, tornadoes and floods might get all the headlines, but in the US heatwaves claim more lives each year than all of these phenomena combined.
The victims of heatwaves are usually the most vulnerable: the sick, the elderly and the very young. As heatwaves become more severe, though, the proportion of the population dying will rise. Even healthy adults acclimatised to heat will succumb if it stays too hot and too humid for too long. To function normally, we have to maintain a core body temperature of around 37 °C. If it rises above about 42 °C, we die.
Exactly why is still not understood. The body diverts blood to the skin to try to cool off, which cuts the blood supply to the gut. One theory is that bacterial toxins from damaged guts start leaking into the bloodstream, eventually causing multiple organ failure.
What is clear is that to prevent our core temperature rising too high, our skin temperature must not exceed 35 °C for more than a few hours. In dry climates sweating will cool the skin sufficiently even in temperatures of 45 °C or more. But in humid climates where the air is nearly saturated with moisture, sweating makes little difference.

https://barringtonstewart.wordpress.com/thermogeddon-when-the-earth-gets-too-hot-for-humans/

Lord of Planar · Sep 16, 2016

Glen Contrarian said:
And why would there be thermal expansion? That would only occur if the oceans are warming, right? Right. And according to most of the AGW-denial crowd, that ain't happening.

Liar.

I call it like I see it, and you are a liar.

Who here says the oceans are not warming?

Come on now... Who!

You warmers are so caught up in the BS, that you have to lie about what the opposition says.

Who says the oceans are not warming?

Glen Contrarian said:
In other words, what you just did was use one of the facts proving that the planet is warming to try to disprove the fact that the planet is warming. :doh

See... You build a strawmen.

LOL...

You make up what you think I mean, but it only proves you are utterly clueless!

Glen Contrarian said:
Either way, has it occurred to you that BOTH the gigatonnes of glacier melt being added to our oceans every year AND the thermal expansion of seawater are combining to account for the rise of the sea levels over much of the world? It's NOT an either-or - it's BOTH.

Yes, it is both. And one can conveniently be diminished by the pundits to make the other look like it is more.

What about the other variables? Do you even know what they are?

I'll bet you don't!

Glen Contrarian · Sep 16, 2016

eohrnberger said:
Actually, the point I was making that no one has responded to was that during the course of the Earth's long history, there were times, extended millions of years in fact, where there were higher levels of CO2 in the atmosphere, and it didn't cause any problems for life. It in fact flourished.

The question I was asking was how these previous 3 times pre-industrial levels of CO2 compared to present day levels of CO2.

The problem with EACH of the examples you present is that the CO2 content was not the only factor that was different in our atmosphere. In each case, the O2 level was significantly higher. I don't know how much experience you do or don't have with elevated O2 levels, but it presents big, big problems when it comes to fires. Imagine what would happen to our forests if the O2 content was as high as it was in any of those instances.

What's more, your examples only address CO2 and O2 - what about the levels of the other gases? What happens when the raw amounts of the other gases remains roughly the same, but only the CO2 and methane levels rise? In other words, your examples are of completely different atmospheres, with completely different concentrations not only of CO2 and O2, but also of methane, of all the noble gases, and particularly of nitrogen. What happened to life in those atmosphere simply cannot be used to presume it would be somehow as good - much less somehow better - with a higher CO2 content today.

What's more, at what point does our increase in CO2 concentration stop? Look at the graph below:

See how it's skyrocketing? AT WHAT POINT DOES IT LEVEL OUT? At what point does it stop? It's already nearly twice what it was 500 years ago - and if we keep going at this rate, will it level at at three times, four times, ten times what it was before? Your examples only address what it was at three times the pre-industrial level...but at the rate we're going, we might well pass that point within the next fifty years. We're into uncharted territory already (since our atmosphere's chemical makeup is completely unlike the examples you presented)...but then we'd be even further off the edge of the map.

So why are you even discussing this matter? What is your purpose in doing so? To learn? To determine fact from fiction? Or is it to shut down those stupid big-government liberals who are going to destroy the economy with the "AGW hoax"? If it's the last...it's no hoax. It's here now, today, and even if we do everything we can to stop it, it's still going to get much worse before it starts getting better...but if we do nothing, we're truly going to leave the edge of the map far behind us.

Glen Contrarian · Sep 16, 2016

Lord of Planar said:
Liar.

I call it like I see it, and you are a liar.

Who here says the oceans are not warming?

Come on now... Who!

You warmers are so caught up in the BS, that you have to lie about what the opposition says.

Who says the oceans are not warming?

See... You build a strawmen.

LOL...

You make up what you think I mean, but it only proves you are utterly clueless!

Yes, it is both. And one can conveniently be diminished by the pundits to make the other look like it is more.

What about the other variables? Do you even know what they are?

I'll bet you don't!

No, I did NOT "build a strawman". Here, from one of the more popular AGW-denial sites:

Oceans are cooling
“Ocean heat touches on the very core of the AGW hypothesis: When all is said and done, if the climate system is not accumulating heat, the hypothesis is invalid.
[…]Now that heat accumulation has stopped (and perhaps even reversed), the tables have turned. The same criteria used to support their hypothesis, is now being used to falsify it.” (William DiPuccio)

Okay? No strawman. Simple fact. I didn't say "all" the AGW crowd - I said "most"...and I base that on the fact that the above is posted on one of the most popular AGW-denial sites.

As to the "other variables", I've seen many presented by AGW deniers. Problem is, y'all's contention that "it's not humans, it's this other variable or that other variable!" is based upon:

(1) the presumption that the overwhelming majority of the world's scientists (not just climatologists, but all the other scientific fields which affect or are affected by the climate) somehow missed these variables, or refused to consider them. This means that the overwhelming majority of the world's scientists are somehow ignorant or stupid or malicious...and this presumption is also a largely baseless ASSUMPTION that the scientific community has never examined these other variables and one-by-one eliminated them; or

(2) (and I've seen this many times) - that most (if not all) scientists who support AGW theory do so with the knowledge that AGW is false, but support AGW because they're afraid of what the scientific community would do to their careers. This claim goes on the assumption that the overwhelming majority of scientists are cowards, unable or unwilling to stand up for what they know to be right...that out of the hundreds of thousands of PhD-holding scientists, only a very small percentage of them are mentally strong enough to stand up for what they know to be right. What this presumption completely misses is that one of the things that brings the most joy to ANY scientist is the opportunity to stand orthodoxy, what the rest of the scientific community knows, on its head. Scientists LOVE to go against the grain...and are anything BUT the monolithic group that many AGW deniers (like our resident Jack Hays) seem to think; or

(3) "It's just a theory and so it can't be trusted!"...without ever bearing in mind that the scientific community's theory is far more stringent than most of us realize. For example, the following are theories, even though most of us non-scientists accept them as solid fact: gravity, general relativity, plate tectonics, black holes (IIRC), and evolution.

What most AGW deniers refuse to consider is that the underlying reason they despise the very idea of AGW has little to do with actual science, and everything to do with politics...particularly given the fact that the quickest way to be declared a RINO (or CINO for conservatives) is to agree with liberals on anything whatsoever...even when all the liberals are doing is agreeing with the overwhelming majority of the world's scientific community.

eohrnberger · Sep 16, 2016

iguanaman said:
Except that most of the "flourishing life" from those times is now extinct and humans along with most living species have never lived in such a warm environment. The fact that this escapes you is telling.

Human being hadn't evolved by those points in time, and if I were to hazard a guess, I'd say that the majority of the species extinction were caused by the Cretaceous–Paleogene extinction event as well as changing climate due to the shifting in plate tectonics. Extinction is part of the natural process after all.

iguanaman said:
https://barringtonstewart.wordpress.com/thermogeddon-when-the-earth-gets-too-hot-for-humans/

Being the most adaptable creatures on the planet, is this really so dire for humans that the Earth warms?
After all, don't we just have to turn up the air conditioner?
(Just joking).

Mean atmospheric O 2 content over period duration	c. 32.5 vol %[1][2] (163 % of modern level)
Mean atmospheric CO 2 content over period duration	c. 800 ppm[3][4] (3 times pre-industrial level)
Mean surface temperature over period duration	c. 14 °C[5][6] (0 °C above modern level)
Sea level (above present day)	Falling from 120 m to present-day level throughout the Mississippian, then rising steadily to about 80 m at end of period[7]

Mean atmospheric O 2 content over period duration	c. 23 vol %[1][2] (115 % of modern level)
Mean atmospheric CO 2 content over period duration	c. 900 ppm[3][4] (3 times pre-industrial level)
Mean surface temperature over period duration	c. 16 °C[5][6] (2 °C above modern level)
Sea level (above present day)	Relatively constant at 60 m (200 ft) in early Permian; plummeting during the middle Permian to a constant −20 m (−66 ft) in the late Permian.[7]

Mean atmospheric O 2 content over period duration	c. 26 vol %[1][2] (130 % of modern level)
Mean atmospheric CO 2 content over period duration	c. 500 ppm[3][4] (2 times pre-industrial level)
Mean surface temperature over period duration	c. 18 °C[5][6] (4 °C above modern level)

Mean atmospheric O2 content over period duration	c. 32.5 vol %[1][2] (163 % of modern level)
Mean atmospheric CO2 content over period duration	c. 800 ppm[3][4] (3 times pre-industrial level)
Mean surface temperature over period duration	c. 14 °C[5][6] (0 °C above modern level)
Sea level (above present day)	Falling from 120 m to present-day level throughout the Mississippian, then rising steadily to about 80 m at end of period[7]

Sea level rise?

Computer Gaming Nerd