Holocene Sea Levels were 2 Meters Higher
1. Are Modern ‘Anthropogenic’ Sea Levels Rising At An Unprecedented Rate? No.
Despite the surge in CO2 concentrations since 1900, the UN’s Intergovernmental Panel on Climate Change (IPCC) has concluded that global sea levels only rose by an average of 1.7 mm/yr during the entire 1901-2010 period, which is a rate of just 0.17 of a meter per century.
During the 1958 to 2014 period, when CO2 emissions rose dramatically, a recent analysis revealed that the rate of sea level rise slowed to between 1.3 mm/yr to 1.5 mm/yr, or just 0.14 of a meter per century.
Frederiske et al.,2018 “Anthropogenic” Global Sea Level Rise Rate (1958-2014): +0.14 of a meter per century
“For the first time, it is shown that for most basins the reconstructed sea level trend and acceleration can be explained by the sum of contributors, as well as a large part of the decadal variability. The global-mean sea level reconstruction shows a trend of 1.5 ± 0.2 mm yr−1 over 1958–2014 (1σ), compared to 1.3 ± 0.1 mm yr−1 for the sum of contributors.”
2. ~15,000 – 11,000 Years Ago, Sea Levels Rose At Rates Of +4 to +6 Meters Per Century
In the past few thousand years, sea levels in some regions rose and fell at rates of + or – 0.5 to 1.1 meters per century. Sea levels during the Medieval Warm Period were+170 centimeters higher than today.
Hansen et al., 2016 Denmark, +1.7 meters higher than present during the Medieval Warm Period
“Continuous record of Holocene sea-level changes … (4900 years BP to present). … The curve reveals eight centennial sea-level oscillations of 0.5-1.1 m superimposed on the general trend of the RSL [relative sea level] curve [relative sea levels ~1.7 m higher than present from 1400 to 1000 years ago].”
Cronin et al., 2017 Global Sea Level Rise Rate: +4 meters per century (14,500 to 14,000 years ago)
“Rates and patterns of global sea level rise (SLR) following the last glacial maximum (LGM) are known from radiometric ages on coral reefs from Barbados, Tahiti, New Guinea, and the Indian Ocean, as well as sediment records from the Sunda Shelf and elsewhere. … Lambeck et al. (2014) estimate mean global rates during the main deglaciation phase of 16.5 to 8.2 kiloannum (ka) [16,500 to 8,200 years ago] at 12 mm yr−1 [+1.2 meters per century] with more rapid SLR [sea level rise] rates (∼ 40 mm yr−1) [+4 meters per century] during meltwater pulse 1A ∼ 14.5–14.0 ka [14,500 to 14,000 years ago].”
Abdul et al., 2017 Global Sea Level Rise Rate: +4 meters per century(11,450 to 11,100 years ago)
“We find that sea level tracked the climate oscillations remarkably well. Sea-level rise was fast in the early Allerød (25 mm yr-1), but decreased smoothly into the Younger Dryas (7 mm yr-1) when the rate plateaued to <4 mm yr-1here termed a sea-level “slow stand”. No evidence was found indicating a jump in sea level at the beginning of the Younger Dryas as proposed by some researchers. Following the “slow-stand”, the rate of sea-level rise accelerated rapidly, producing the 14 ± 2 m sea-level jump known as MWP-1B; occurred between 11.45 and 11.1 kyr BP with peak sea-level rise reaching 40 mm yr-1 [+4 meters per century].”
Ivanovic et al., 2017 Northern Hemisphere Sea Level Rise Rate: +3.5 to +6.5 meters per century (~14,500 years ago)
“During the Last Glacial Maximum 26–19 thousand years ago (ka), a vast ice sheet stretched over North America [Clark et al., 2009]. In subsequent millennia, as the climate warmed and this ice sheet decayed, large volumes of meltwater flooded to the oceans [Tarasov and Peltier, 2006; Wickert, 2016]. This period, known as the “last deglaciation,” included episodes of abrupt climate change, such as the Bølling warming [~14.7–14.5 ka], when Northern Hemisphere temperatures increased by 4–5°C in just a few decades [Lea et al., 2003; Buizert et al., 2014], coinciding with a 12–22 m sea level rise in less than 340 years [3.5 to 6.5 meters per century] (Meltwater Pulse 1a (MWP1a)) [Deschamps et al., 2012].”
Zecchin et al., 2015 Regional Sea Level Rise Rate: +6 meters per century(14,500-11,500 years ago)
“[M]elt-water pulses have punctuated the post-glacial relative sea-level rise with rates up to 60 mm/yr. [6 meters per century] for a few centuries.”
3. Over 70 Papers Affirm Sea Levels Were 2+ Meters Higher Than Now A Few Thousand Years Ago When CO2 Levels Were ‘Safe’
70+ Papers: Sea Levels 2+ m Higher 9,000-4,000 Years Ago While CO2 Levels Were ‘Safe’ (265 ppm) More Here
Before the advent of the industrial revolution in the late 18th to early 19th centuries, carbon dioxide (CO2) concentrations hovered between 260 to 280 parts per million (ppm).
Within the last century, atmospheric CO2 concentrations have risen dramatically. Just recently they eclipsed 400 ppm.
Scientists like Dr. James Hansen have concluded that pre-industrial CO2 levels were climatically ideal. Though less optimal, atmospheric CO2 concentrations up to 350 ppm have been characterized as climatically “safe”.
However, CO2 concentrations above 350 ppm are thought to be dangerous to the Earth system. It is believed that such “high” concentrations could lead to rapid warming, glacier and ice sheet melt, and a harrowing sea level rise of 10 feet within 50 years.
To reach those catastrophic levels (10 feet within 50 years) predicted by proponents of sea level rise alarmism, the current “anthropogenic” change rate of +0.14 of a centimeter per year (since 1958) will need immediately explode into +6.1 centimeters per year.
The likelihood of this happening is remote, especially considering Greenland and Antarctica combined only contributed a grand total of 1.54 cm since 1958 (Frederiske et al., 2018).
It is becoming more and more apparent that sea levels rise and fall without any obvious connection to CO2 concentrations.
And if an anthropogenic signal cannot be conspicuously connected to sea level rise (as scientists have noted), then the greatest perceived existential threat promulgated by advocates of dangerous man-made global warming will no longer be regarded as even worth considering.
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