[Coral-List] Sea Level rise

[Richard Dodge]

https://climate.nasa.gov/ask-nasa-climate/2949/why-milankovitch-orbital-cycles-cant-explain-earths-current-warming/#:~:text=Milankovitch%20cycles%20include%20the%20shape,is%20pointed%20(its%20precession).

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From: Coral-List <coral-list-bounces at coral.aoml.noaa.gov> On Behalf Of Eugene Shinn via Coral-List
Sent: Friday, March 4, 2022 1:06 PM
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Subject: [Coral-List] Sea Level rise

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Dear Listers, What always bothers me about the relation between CO2 and temperature is how can we be sure anthropogenic CO2 is the cause of rising temperature and sea level rise. Ice cores are not my field of study but I know that abundant data from ice cores, such as the Vostok core, indicate a relationship between temperature and CO2. Clearly the
CO2 associated with temperature increases in the past were not caused by burning fossil fuels. The ice cores show 4-distinct evenly spaced temperature rises during the Pleistocene. In addition, the rise in CO2 usually peaks a few hundred years after the peak temperature. I suppose that can be explained by CO2 expelled from the oceans due to increasing warmth. But what caused the temperature increase in the first place?

Cores of the Pleistocene limestone that built the Florida Keys also show
3 to 4 periods of climate temperature change. The changes are marked by iron rich red/brown soil layers caping each sedimentary unit. These layers are identical to the well-studied soil stone layers presently forming on the surface of Florida Keys limestone. It is clear the Pleistocene layers represent periods of limestone exposure and thus indicate lowered sea level. I am guessing these sea level fluctuations are analogous to the fluctuations indicated in ice cores. I think we can safely conclude the red/brown layers in the Pleistocene Keys limestone indicate sea level fluctuations caused by something other than burning fossil fuel.

How much sea level fluctuation the Pleistocene ice core temperature changes represent is not generally known, but there is good geological evidence that the last one, the 125,000 year-old temperature increase (known as isotope stage 5 e) raised sea level around 27 ft above present. I live on land formed at that time as are people living in the Florida Keys. That the land formed when sea level was around 27 ft higher than today could not have been caused by humans burning fossil fuel. This may suggest the present sea level rise might also go as high as it did 125,000 years ago. So how do we explain all this. Presumably the Carbon isotopes in the present atmospheres CO2 identify some as the result of burning fossil fuel. Can we identify those same isotopes in the 125,000 year old temperature rise? I suspect the answer is no. There were not enough people back then to create excess CO2. This suggests we still do not know what caused stage 5 e. What ever caused sea level rise back then may also be the cause of the present sea level rise. Or maybe rising CO2 is not what is causing the present rise. I am just asking the question? I think we have a long way to go before we truly know what is causing the present sea level rise? And, will it rise as high as it did during stage 5 e? Possibly we need to remove politics from the question before we have the correct answer? Gene _______________________________________________
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