In a publish-or-perish world in which the profusion of “peer reviewed” journals is connected with the mass production of uninteresting or over-hyped results, sometimes both, and a decline in actual breakthroughs, we are excited to read that “Earth’s Core Has Stopped and May Be Reversing Direction, Study Says/ The surprising finding might solve longstanding mysteries about climate and geological phenomena.” We didn’t know there were “longstanding mysteries about climate” since we were told the science is, um, settled. Isn’t it?
No. Not even slightly. Although we did know, unlike the author of this piece in Vice about the study in Nature Geoscience, that climate change exhibits strongly cyclical characteristics, albeit the irregular cycles associated with non-linear phenomena. They on the other hand have now discovered that:
“The mind-boggling results suggest that Earth’s center pauses and reverses direction on a periodic cycle lasting about 60 to 70 years, a discovery that might solve longstanding mysteries about climate and geological phenomena that occur on a similar timeframe, and that affect life on our planet.”
So now we want to get their take on how humans have been causing climatic cyclical events on that scale for however long it’s been. The story doesn’t get curious about it, but if it’s been, say, centuries, or millennia, or millions of years, and “Extended Data Fig. 8” in the actual paper suggests that it’s been happening constantly for an open-ended period, some might incautiously conclude that climate always has been highly variable for natural reasons and, um, might still be.
The Washington Post story on the same study says that:
“The provocative findings come after years of research and deep scientific disagreements about the core and how it influences some of the most fundamental aspects of our planet, including the length of a day and fluctuations in Earth’s magnetic field.”
And if you were aware of the Svensmark hypothesis that changing intensities of solar wind affect the way cosmic rays penetrate that magnetic field, in turn affecting cloud cover that has a major impact on climate, you might also think that understanding other factors that impact the magnetic field would also be important for understanding natural variability. If. Instead the Post story does not contain the word “climate” at all.
Speaking of natural variability, the Vice piece quotes the researchers at one point that:
“The linkage [between “the deepest and shallowest layers” of the Earth], however, is less clear at the moment. The gravitational coupling between the inner core and the mantle may cause deformation at the Earth’s surface, which would affect the sea level. The changes of the sea level and the Earth’s rotation may affect the global atmosphere circulation and temperature. The resonance of different systems may also amplify the mutual interactions.”
Oh my. So all that panic about rising seas due to completely understood phenomena might have been unreliable? What a shock.
Even so, the lure of settled science is powerful. The piece goes on to claim that:
“this is more or less the plot of the 2003 disaster film The Core, but there’s no need to worry about averting an impending apocalypse by nuking the center of Earth. While the core’s rotation influences Earth’s surface environment, scientists think this periodic spin switch is a normal part of its behavior that does not pose risks for life on our planet.”
Scientists think. About something they only just discovered is totally different than they thought. The science changes repeatedly (like climate) but at any given moment is always settled. (Here we’re tempted to make a calculus joke about a highly variable function whose integral is zero but will resist.) Instead we will note first that the Post is less sanguine:
“‘It’s only contentious because we can’t figure it out,’ said John Vidale, a geophysicist at the University of Southern California. ‘It’s probably benign, but we don’t want to have things we don’t understand deep in the Earth.’”
Still, we do have them, don’t we? And on the surface.
Next we will quote the bit in the Vice story immediately following the previous quotation about The Core:
“Earth’s inner core is a solid metal ball that is 75 percent the size of the Moon. It can spin at different speeds and directions compared to our planet because it is nestled within a liquid outer core, but scientists are not sure exactly how fast it spins or whether its speed varies over time.”
Which amounts to pretty considerable uncertainty about something that your basic geology primers describe as though scientists had gone and looked and come back with selfies of the liquid and solid bits. But, the Post notes, Paul Richards, a Columbia University seismologist who worked with one of the authors:
“cautioned that things get speculative quickly when trying to understand the influence of the core on other phenomena. That’s because the behavior of the core itself is still a contested question – with simplistic assumptions increasingly refined over the years. For example, there are lines of evidence to support other ideas about how Earth’s core is behaving.”
In fact it turns out that the Earth’s core is so far away, buried beneath so much rock and other stuff only Jules Verne’s prose could tunnel through, that everything we “know” about it is based on highly ingenious but tenuous extrapolation from very limited data, basically interpreting seismic waves as they bounce back through who-knows-what along some mysterious path or another. Thus, Vice reports “some scientists think the wave patterns arise from phenomena at the boundary between the outer and inner core” whereas others vehemently disagree.
The bottom line is that the situation is complex. (As it also is with star cores, Scientific American lets us know in its idle moments while not intoning that “Antiabortion Heartbeat Bills Are neither Morally nor Legally Sound” which the incautious might have thought was a bit outside their ambit). And as Vice also says:
“The results offer an unprecedented look at the searing pit of our planet, a region that continues to evade clear explanation, and it also has big implications for understanding the familiar world we inhabit on Earth’s surface.”
We just don’t know what they are. Settled science, non-climate style.
BTW in its piece entitled “‘Disruptive’ science has declined — and no one knows why” that we referred to right at the outset, with the subhed “The proportion of publications that send a field in a new direction has plummeted over the past half-century”, Nature does not touch on the uncomfortable possibility that we live in an era of enforced conformity in which everyone is a tattooed individualist with the same artificial hair colour, and climate “skeptics” are hounded right out of the field.