THIS POST IS AN ANALYSIS OF SEA LEVEL DYNAMICS IN THE HOLOCENE PRESENTED BY STEVE KOONIN

LINK TO SOURCE: https://tambonthongchai.com/2021/03/22/steve-koonin-lecture/

The data for sea level rise is presented in the graphic below. The left frame shows global mean sea level reconstruction since 1900 derived from a network of tide guages around the world. It shows sea level rise of about 200mm over a period of 100 years at an average rate of about 2mm per year. On the right frame it shows satellite data for sea level since 1992. The satellite data global mean sea level rise are consistent with the reconstruction from tidal guages shown in the left frame.

The significant sea level rise events at the end of the last glaciation into the Holocene interglacialis shown in the chart below. It shows that sea level rise predates the industrial revolution. The sea level has been rising for 15,000 years and has risen by 120 meters (120,000 mm or an average of 8mm/year) and the rate of rise has not gone up but rather the rate of rise has gradually flattened out to a negligible percentage of the sea level rise at the initiation of the Holocene. This history makes it difficult to attribute the observed sea level rise in the post industrial era to humans.

Here is how the consensus climate science looks at this issue. The essential argument here is that current observed sea level rise is faster than what we would expect from an extrapolation of the historical deglaciation sea level and that difference is human caused. They say that the sea level rise in the most recent century is greater than the previous century and that therefore it is human caused.

Here Koonin says that if you look at the data since 1950 when NASA GISS and James Hansen identifiy as the time that global warming started, what we find is shown in the graphic below. It shows that natural variability in sea level rise is too large to intepret the tail end of it as a human caused sea level rise.

Projections of future sea level rise. On the left frame in the graphic below we see the projections of sea level rise where future rates of rise are much higher and accelerating. Comparing that SLR behavior with observations in the right frame we find no evidence of such acceleration in a time of global warming.