NOAA shows a modest 3.2 mm sea level rise over the last year. How significant is the current sea level raise from a geological perspective?
May 26 2018-Recently in the Meeting minds article, “A Climate Change Perspective – Relating Things to the Early Holocene and Eemian”, we reported that the last 2 years the oceans have suspended rising. However, recently from NOAA has reported a modest sea rise increase.
Since 1880 the ocean began to rise briskly, climbing a total of 210 mm (8.3 in) through 2009- about 7 inches a century. However, if you put that in a historical perspective; 19,000 to 6,000 years ago the sea level raise rate was roughly 529% to 2814% higher then today. Oceans during this time raised close to 120 metres (4,724 inches), this would be 56,915% percent larger then the 8.3 inch sea level raise since 1880. This all happened from 18,000 to 4,000 years before the birth of Jesus. National Oceanography Centre "Global sea level rose by a total of more than 120 metres as the vast ice sheets of the last Ice Age melted back. This melt-back lasted from about 19,000 to about 6,000 years ago, meaning that the average rate of sea-level rise was roughly 1 metre (37 inches) per century. Previous studies of sea-level change at individual locations have suggested that the gradual rise may have been marked by abrupt ‘jumps’ of sea-level rise at rates that approached 5 (197 inches) metres per century. Their analyses indicate that the gradual rise at an average rate of 1 metre per century was interrupted by two periods with rates of rise up to 2.5 metres (98 inches) per century, between 15 and 13 thousand years ago, and between 11 and 9 thousand years ago."
In this article we would like to look at the sea level significance from a geological perspective. We will briefly compare the current sea level rise to several time scales; 500 million years ago, 450 thousand years ago, 1 mya, 140kya, 20 kya, 18kya, and a 140kya. The Graph below represents estimated sea level over the last 500 million years. You will see in the left hand side where the current Holocene is located. Sea level heights over the last 25 million years compared to the last 500 million years is roughly lower then ninety percent of time. Slightly different estimates exist based on different sources of analysis and evidence. So, the graphs in this article should be taken as rough estimates.
Below is a graph the shows the estimated sea level over the past 450 thousand years. The Red circle shows where the Holocene is and where the modern human era is located. What stands out when you look at this graph is that over the last 450 thousand years there are potentially 7 peaks where the sea level was slightly higher than the current conditions. Also, what is intriguing is the sea level raised 120 meters increase, starting 20 thousand years ago, before human beings started altering the climate.
“Modern science has discovered that orbital variation known as the Milankovitch cycle have been causing these milder events known as interstadials. Climate change driven by Orbital variation may not be limited to the Ice Age. It has been observed that orbital variation may have been a very important driver for climate change for 1.4 billion years .”
Below we show two graphs. The top graph compares sea level over the last one million years and the bottom graph compares sea level rise over the last 140 thousand years.
Even though the graph above only shows one million years the current Pleistocene started roughly 2.5 million years ago. We just transcribed in this article above that the current sea level may have been higher at potentially 7 or more peaks the last 450 thousand years depending on source of information. However, if you look at the graph below you will observe that the sea level was potentially higher than current conditions almost 16 times between 2.5 million years ago and 1 million years ago. Not only that; we report in "Glaciers or Rising Oceans; Damned if you do, damned if don’t, And maybe both” Remarkably,
“There is even evidence that Greenland may have been ice free for 280,000 years about 1.1 million years ago. What is even more remarkable is that many ice age mega fauna that went extinct 11,000 years ago survived the previous interstadials even though the oceans were higher and the temperatures were warmer; forests reached North Cape, Norway….”
It is astounding to think that 1.2 million years ago Greenland may have been ice free for 280 thousand years…
Below is a graph the shows the sea level over the last 20 thousand years in relation to current conditions in meters.
Below is a graph that shows the increase of the sea level as a rate measured in centimeter per century. As you can see in the graph below the large blue box is the natural variation and the small red circle is recent history where modern humans started to alter the environment.
“Let’s make a trip back to North America 30,000 to 15,000 years ago. The oceans are close to a 120 meters lower, the majority of Canada is covered by glaciers, and the landscape was significantly cooler. The extinct mega fauna such as the Western Horse, North American Lions, Short faced bears, Columbian Mammoth, Giant bison, American Mastodons (5mya-8.5kya), Jefferson’s ground sloth, Dire Wolves, Camelops (7ft at shoulder, 4mya-11kya), North American Cheetah, Stag-Moose, Saber-tooth cat, Shrub ox, American Mountain Deer, Beautiful Armadillo (1.2m length, 1.8mya-11kya), Pygmy Mammoth (8.5 kya, Channel Islands, CA), Giant Beaver, Woolly Mammoth, and etc dot the landscape. What is really unique about these animals is that many of them existed for several million years before their extinction? They have crossed the land bridge between continents; they survived over a dozen interglacial periods. The last two interglacials had temperatures even slightly warmer then current temperatures. Even more, during the Eemian the oceans were over 20-30 feet higher then present sea level. This time represented extraordinary natural wildlife living in a world with extraordinary hydrological events that dwarf current events. As you can see in the picture below shows that the full extent of the glaciers in North America was reached about 18,000 years ago. The glaciers then started to retreat North East for the next 12,000 years until 6,000 years ago. Coincidentally, 6,000 years ago is when the Sahara Desert started to become a desert.”
Below is a similar graph as above, showing the sea level rise as a rate measured by cm per century? If you look at the bottom right hand corner you will see the arrow that leads to another graph that shows the sea level rise over the last 140 years. It is estimated that the oceans have risen about 8 inches since 1880. One may be concerned if an eight inch sea level rise happened in the last 20 years, but the sea has only risen roughly 3.5 inches in the last 30 years.
“And some accuracy in predicting climate change can be lost in background noise and variation caused by forest, aerosols, sun spots, and natural occurrence. A recent statement about deforestation reads as the following.
"When the impacts on biogenic SOA, O3 and CH4 are combined, global deforestation exerts an overall positive RF of between +81.1 and +135.9 mW m−2 through changes to short-lived climate forcers (SLCF). Taking these additional biogeochemical impacts into account increases the net positive RF of complete global deforestation, due to changes in CO2 and surface albedo, by 7-11%. Overall, our work suggests that deforestation has a stronger warming impact on climate than previously thought."
Other variations in climate could be Chaotic Solar system, sun spots, climate inertia, and ultra-hypersensitive collection of new data by new technological means that did not exist 50 years ago. Recently CLOUD said that aerosols may be underestimated in modeling attempts for climate change and suggest that the scientific community reduces it's "climate sensitivity." There statement below reads as the following.
"Early this year, CLOUD reported in Nature the discovery that aerosol particles can form in the atmosphere purely from organic vapours produced naturally by the biosphere (CERN Courier July/August 2016 p11). In a separate modelling paper published recently in PNAS, CLOUD shows that such pure biogenic nucleation was the dominant source of particles in the pristine pre-industrial atmosphere. By raising the baseline aerosol state, this process significantly reduces the estimated aerosol radiative forcing from anthropogenic activities and, in turn, reduces modelled climate sensitivities. “This is a huge step for atmospheric science,” says lead-author Ken Carslaw of the University of Leeds, UK. “It’s vital that we build climate models on experimental measurements and sound understanding, otherwise we cannot rely on them to predict the future. Eventually, when these processes get implemented in climate models, we will have much more confidence in aerosol effects on climate. Already, results from CLOUD suggest that estimates of high climate sensitivity may have to be revised downwards.””
In the graph below we would like to draw your attention to the small red circles. These circles represent potential glacier peaks over the last 450 thousand years; including 20 thousand years ago. If you follow the arrows from those circles to the next picture you will see an illustration of what North America potentially looked like during those time periods. You will notice that almost half of North America was covered in glaciers during these time periods. These huge extreme climatic changes most likely happened because of very small orbital variations in earth’s rotation around the sun.
One of the leading debates in modern climate change science right now is how the current interglacial period relates to previous interglacial events. One of the most common comparisons of the current interglacial period is the Eemian period that happened roughly 115 to 130 thousand years ago. During this time period the Eemian sea level was 20-30 feet higher. Many global warming skeptics suggest that current warming trends might be similar to Eemian and would not be surprised if the sea level raised another 20 or 30 feet from natural causes. Many global warming scholars and researchers however suggest that the current conditions do not match the Eemian interglacial period because of Artic ocean temperatures, peak sea level rise vs interglacial timeline, and etc. However, there is a better interglacial period to compare to the current interglacial period. In our article “Solar Forcing Comparison between the Holocene and Anglian Interglacial Periods Related by Eccentricity” we show that“
“In attempts to understand the current interglacial period, known as the Holocene, scientists have observed that the Eemian period is not quite like the Holocene because it had a sharper temperature increase with no Younger Dryas effect, higher temperatures, and a temperature peak lasting less then 10,000 years. Some of the reasons for this are explained by eccentricity,
“Eccentricity is important because it regulates the strength of polar maximum summer insolation caused by precession of the equinoxes every 21,000 years. Precession determines the distance from the sun during a Polar summer. If summer coincides with the earth’s perihelion then summer insolation can be up to 20% higher than average. However if the earth’s orbit is nearly circular, as it is today, then precession has little effect at all. That is why we have about 12000 years left before cooling begins.”October 4, 2016 by Clive Best, When is the next ice age due?
Two observations from these charts come to play. The first is the current interglacial period, Holocene, is only half over. And if the Holocene is anything like the Anglian interglacial period temperatures are set to continue to rise if they correlate with EPICA (European Project for Ice Coring in Antarctica) temperatures reported for the Anglian interglacial period.””
We would like to conclude in this article by asserting our stance that Humankind is altering many ecosystems in the world, degrading natural reference state habitats, and having an unknown effect on the climate. And it is almost beyond a shadow of doubt that Carbon Dioxide Emissions have increase about 50% from 280 ppm to about 410 ppm. However, we would like to point out that this number is not set in stone and is in flux due to; seasonal variations, loss of natural carbon sequestration sinks from deforestation, and thawing of the permafrost in the arctic. However, as we pointed out above, with the Anglian Glacier Analog, temperatures might continue to moderately increase naturally. Furthermore, some warming may be related to urbanization, deforestation, orbital variation cycles, natural weather cycles, and etc. But, how does this compared to temperature changes at the beginning of the current interglacial period? We recently reported in ,” Glaciers or Rising Oceans; Damned if you do, damned if don’t, And Maybe Both”
We do see a small modest increase in the average global temperature. However, as a rough estimate, the last glacial advance was 9-12 degrees Fahrenheit cooler than the temperatures of the 20th Century. That means that the temperature increased 20-28% before human beings started to record and measure temperatures. It also has to be taken into account most of that temperature change happened in a very short period of time over 11,000 years ago. This compared to a 2-3% temperature increase in the last century. This does not even take into account that over half of the current temperature increase might be natural, back ground noise, or hyper sensitivity from technological advances in temperature detection.Plus, during the Emmian period Earth saw temperatures higher then our current global averages. And it has been observed that temperatures in the Antarctica were higher in the last two inter-glacial periods then the current temperatures. What they are also finding is that the global temperatures spiked and went up towards the end of several inter-glacial periods. This suggest that an increase in temperature might be normal, including an additional sea level rise of another 20-30 feet. This might be a common occurrence that drives the earth into a glacial period. A research paper from 2009 showed Antarctica in a previous inter glacial may have been 6 degrees Celsius higher then today. In a recent lecture by Ayako Abe-Ouchi, Atmosphere and Ocean Research Institute at The University of Tokyo, lectures on Modeling the 100,000-year Glacial-interglacial Cycles, says, "carbon dioxide is a very important amplifier, but not a driver."