|Fig. 1 Stockholm "way back then"|
I. Way Back When
There is some changing understanding within the scientific community which concerns the roles played by thermal expansion and contraction.
As more data enters the picture, from closer analysis of PSMSL tide gauge records to utilization of modern satellite data, thermal expansion concepts are being put to task.
The past understanding went something like:
"This thermal expansion was the main driver of global sea level rise for 75 to 100 years after the start of the Industrial Revolution. However, the share of thermal expansion in global sea level rise has declined in recent decades ..."(Union of Concerned Scientists, p. 2 PDF, emphasis added). If that is so, then thermal expansion was not doing such a good job of making sea level rise in some places (Fig. 1).
For example, take a look at Sweden and areas near Sweden (Proof of Concept - 5).
And even areas far away from Sweden were not phased by thermal expansion or contraction (Proof of Concept - 3).
It was the humble melting of the Cryosphere by the Ignorati "what done it" (Humble Oil-Qaeda).
II. Current Thinking
A more recent scientific comment puts it this way:
"Observations from the Jason series have revolutionized scientists' understanding of contemporary sea level rise and its causes. We know that today's sea level rise is about one-third the result of the warming of existing ocean water, with the remainder [two-thirds] coming from melting land ice."(NASA, emphasis added). The revolution from "as surface (atmosphere, land) warming increases thermal expansion decreases" (even though 93% of that global warming ends up in the oceans) is morphing into one that passes the smell test.
It seems strange for scientists to have believed that as warming was consistently increasing following the Industrial Revolution of 1750 (as shown by GISS records: On The More Robust Sea Level Computation Techniques - 3) that thermal expansion would have been diminishing rather than increasing along the way.
III. Sir Isaac Newton and The Cryosphere
The cause of the beginning of sea level fall, circa 1785 (of the type shown in Fig. 1 in our era, the Anthropocene) is of course unrelated to thermal expansion or even thermal contraction.
It's a Newtonian phenomenon:
"There’s much that can still be done with GRACE’s archival data, says Isabella Velicogna, a geophysicist at the University of California, Irvine. For example, Velicogna and her colleagues recently used GRACE data to observe for the first time a strange, counterintuitive effect: Melting ice sheets in Greenland and Antarctica are pouring water into the oceans and adding to sea level rise. But the lost ice also means lost gravity—and so sea levels in the immediate vicinity of the ice sheets actually drop, while ocean levels half a world away are goosed. The dynamic, called sea level fingerprints, had wide acceptance in the field, but GRACE provided the first direct confirmation that it was happening."(Science, emphasis added). Sea level was falling in areas near many of the ice sheet concentrations of the Cryosphere, and still are (The Gravity of Sea Level Change, 2, 3, 4).
It helps to engender understanding when scientists acquire all of the published data on a subject (such as Woodward (1888)) prior to taking up and defending smelly positions (The Warming Science Commentariat - 3).
IV. Say "Stable" So You Don't Scare The Hoi Polloi
Orders from on Humble Oil-Qaeda high have always been to tell the hoi polloi to "move along folks, nothing to see here":
"The prevailing view among specialists has been that East Antarctica is stable, but I don’t think we really know,” said Rignot. “Some of the signs we see in the satellite data right now are kind of red flags that these glaciers might not be as stable as we once thought. There’s always a lot of attention paid by the media to the changes we see now, but as scientists our priority remains what the changes could be tomorrow.”(Science, emphasis added). That was the Ignorati hard at work to make us "stable" (Antarctica 2.0, 2).
Savvy scientists were aware of it, however, such as Dr. James Hansen:
(On Thermal Expansion & Thermal Contraction - 8). That Hansen dood is a good grandpa too (We Hold These Truths to be Self-Evident)."I suspect the existence of what I call the `John Mercer effect'. Mercer (1978) suggested that global warming from burning of fossil fuels could lead to disastrous disintegration of the West Antarctic ice sheet, with a sea level rise of several meters worldwide. This was during the era when global warming was beginning to get attention from the United States Department of Energy and other science agencies. I noticed that scientists who disputed Mercer, suggesting that his paper was alarmist, were treated as being more authoritative.
It was not obvious who was right on the science, but it seemed to me, and I believe to most scientists, that the scientists preaching caution and downplaying the dangers of climate change fared better in receipt of research funding. Drawing attention to the dangers of global warming may or may not have helped increase funding for relevant scientific areas, but it surely did not help individuals like Mercer who stuck their heads out. I could vouch for that from my own experience. After I published a paper (Hansen et al 1981) that described likely climate effects of fossil fuel use, the Department of Energy reversed a decision to fund our research, specifically highlighting and criticizing aspects of that paper at a workshop in Coolfont, West Virginia and in publication (MacCracken 1983).
I believe there is a pressure on scientists to be conservative. Papers are accepted for publication more readily if they do not push too far and are larded with caveats. Caveats are essential to science, being born in skepticism, which is essential to the process of investigation and verification. But there is a question of degree. A tendency for `gradualism' as new evidence comes to light may be ill-suited for communication, when an issue with a short time fuse is concerned."
On the western front of Antarctica, one of the more important things that ocean warming can do, and is doing, is to weaken the ice shelves.
Which is a major problem.
Thwaites & Pine Island ice shelf loss threaten to eventually unleash about 21 feet of sea level change, a quantity that equals all of Greenland's threat:
"The origin of the rift in the Pine Island Glacier would have gone unseen, too, except that the Landsat 8 images Howat and his team were analyzing happened to be taken when the sun was low in the sky. Long shadows cast across the ice drew the team’s attention to the valley that had formed there.(West Antarctic Ice Shelf breaking up from the inside out, AGU, emphasis added). Those ice doods be knowin' (AGU Scientific Integrity) !
“The really troubling thing is that there are many of these valleys further up-glacier,” Howat added. “If they are actually sites of weakness that are prone to rifting, we could potentially see more accelerated ice loss in Antarctica.”
More than half of the world’s fresh water is frozen in Antarctica. The Pine Island Glacier and its nearby twin, the Thwaites Glacier, sit at the outer edge of one of the most active ice streams on the continent. Like corks in a bottle, they block the ice flow and keep nearly 10 percent of the West Antarctic Ice Sheet from draining into the sea"
“This kind of rifting behavior provides another mechanism for rapid retreat of these glaciers, adding to the probability that we may see significant collapse of West Antarctica in our lifetimes”
The next post in this series is here, the previous post in this series is here.