Guest “trying not to nitpick” by David Middleton

An Ancient Meltwater Pulse Raised Sea Levels by 18 Meters
Meltwater pulse 1A, a period of rapid sea level rise after the last deglaciation, was powered by melting ice from North America and Scandinavia, according to new research.

By Tim Hornyak  24 hours ago

The period of time when sea levels shot up at the end of the last glacial period, roughly 14,600 years ago, is known as meltwater pulse 1A (MWP-1A). Ever since this pulse was identified from coral records in 1989, the origins of the meltwater have been the subject of debate. Some researchers have hypothesized that Antarctica was the major source of the meltwater, whereas other scientists have suggested that it came from the Northern Hemisphere.

A new study in Nature Communications has concluded that melting ice sheets in North America, followed by Scandinavia, were the dominant drivers of MWP-1A and that the world’s mean sea level rise was 17.9 meters over 500 years.



The Climatariat has been desperately trying to blame Meltwater Pulse 1A on Antarctic marine ice cliff instability (MICI) ever since they first identified it in 1989, right after Al Gore invented Global Warming. Their poster child for this phenomena was Greenland’s Jakobshavn Isbrae glacier, which suddenly stopped cooperating in 2016. In their typical style, the Climatariat quickly changed the Chicken Little cackle from “Run Away! The glaciers are shrinking!” to “Run Away! The glaciers are growing!”

The paper, Lin et al., 2021, supports the obvious explanation of Meltwater Pulse 1A.

Figure 1. Late Pleistocene to Early Holocene deglaciation. (Illinois State Museum)

The full text of the paper is available and worth reading. The Eos article on the other hand…

Meltwater pulse 1A, a period of rapid sea level rise after the last deglaciation…


Meltwater Pulse 1A (MWP 1A) occurred rather early on during the last deglaciation, not afterwards.

Figure 2. Global seal level rise during Holocene Transgression. MWP 1A occurred ~14.6 kya. Note the error bar is ±12 meters.
(Siddall et al., 2003)

Then there was the obligatory and gratuitous…

Insights on Climate Change Today
Yusuke Yokoyama, a professor at the University of Tokyo’s Atmosphere and Ocean Research Institute who was not involved in the study, said the new research is a possible answer to the question of meltwater sources for MWP-1A, but that the debate is far from over.


The “not involved in the study” professor’s main beef was with the choice of the radiometric dating method… However, at no point did any contributor to the article provide any “insights on climate change today” because there are none.


Hornyak, T. (2021), An ancient meltwater pulse raised sea levels by 18 meters, Eos, 102, Published on 02 June 2021.

Lin, Y., Hibbert, F.D., Whitehouse, P.L. et al. A reconciled solution of Meltwater Pulse 1A sources using sea-level fingerprinting. Nat Commun 12, 2015 (2021).

Siddall M, Rohling EJ, Almogi-Labin A, Hemleben C, Meischner D, Scmelzer I, Smeed DA (2003). “Sea-level fluctuations during the last glacial cycle”. Nature 423:853–858

via Watts Up With That?

June 3, 2021