Whereabouts of the North American Shelf

The concept of plate tectonics did not yet exist at this time. The latest theory of continental drift is that it is due to mantle convection.

- ほうこうおんち

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Matsuoka was entrusted with important data from a research institution.

It consisted of seismic waveform records documenting the likely date and time of North America's disappearance, recorded by institutions such as the Earthquake Research Institute of the University of Tokyo, the Central Meteorological Observatory of the Ministry of Education, and local meteorological stations. In addition, the data included copies of all kinds of geophysical observations conducted in Japan, such as tidal records, secondary oscillation records, and atmospheric pressure changes. If anyone other than Matsuoka had transported the data, it could have been suspected as providing intelligence to foreign spies.

Some copies of the data were hand-carried back to their home country by an envoy who visited Japan last year to express gratitude for the conclusion of the Third Anglo-Japanese Alliance. By now, it is likely being analyzed at the University of Cambridge.

Matsuoka brought part of the data to the Arctic Ocean in a carefully moisture-proofed bag because leading scholars in oceanography and geophysics from around the world had gathered there. Rather than returning to London, he wanted to analyze the data on-site, comparing it with real-world conditions.

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"This is........."

Japan, a country prone to earthquakes, possessed data that European scholars coveted. It was abundant in quantity, quality, and variety. With the disappearance of the United States—once a country of greater scientific observation and research—Japan had become the world's leading powerhouse in earthquake, oceanographic, and meteorological sciences. Europe had recorded its own data as well. By comparing it with the data from Japan on the Pacific side, they could verify whether their pre-established hypotheses were correct.

"The way North America disappeared is not natural. It may, in fact, be artificial."

The person who made this statement was Alexander du Toit, a South African geologist who studied at the University of Glasgow in London.

A supporter of Alfred Wegener's continental drift theory, du Toit proposed his own hypothesis that two supercontinents, Laurasia and Gondwana, once existed in both the Northern and Southern Hemispheres. He had also touched upon the Alpine-Himalayan orogeny, making him one of the world's leading experts on continental movement and vertical displacement.

"Did you say artificial?"

"Yes. These seismic waveforms seem completely different from those of a typical earthquake. It appears that over time, seawater gradually infiltrated the area where land had disappeared, causing seismic activity due to the shift in water mass."

"This atmospheric pressure data, too. It's been steadily decreasing over time."

Responding to this observation was Vilhelm Bjerknes, an oceanographer and meteorologist from the Germany-occupied Norway, currently residing in the UK. Unfortunately, his son, Jacob Bjerknes, had moved to the United States in 1940 to become a meteorology professor at UCLA and perished along with North America.

He had studied atmospheric changes over time and pioneered scientific weather prediction using fluid dynamics and thermodynamics instead of empirical methods. Pressure, wind direction, and tidal level fluctuations all displayed strange numerical values.

Sir Geoffrey Ingram Taylor, a leading British authority on fluid and solid mechanics, remarked, "As expected, Japan's data makes it clear that the North American continent did not disappear instantly but gradually over time. Of course, in geological terms, it was still quite rapid."

Had the continent vanished in an instant, there would have been significant tremors due to the abrupt loss of mass, and the sudden change in sea level would have resulted in tsunami damage far greater than what had been observed. Taylor, who had also studied underwater explosions, understood well what would happen if sudden changes occurred beneath the water's surface.

If something as massive as North America had vanished in an instant, the resulting vacuum would have caused seawater to rush in rapidly, producing shockwaves and measurable reflections on the ocean surface and seabed. However, no such data had been observed anywhere. The land seemed to have disappeared gradually, allowing seawater to seep in slowly.

"As we suspected, vertical displacement alone cannot explain this phenomenon," remarked Arthur Holmes, the British geologist who proposed the concept of mantle convection.

Among this gathering of Europe's top scholars, Japan had sent only one representative: the oceanographer Takashi Uda.

The renowned seismologist Akitsune Imamura, who developed the Imamura seismometer, had expressed his desire to attend. However, due to his advanced age and the honor of having been awarded the Junior Third Rank, he was not permitted to travel to the unfamiliar Arctic region.

This reflected Japan's attitude toward science—while they could have assembled a major project team to collaborate with Europe, bureaucratic attitudes, hierarchical mindsets, and a reluctance to take risks resulted in a delegation filled with officials rather than pioneering scientists. Ultimately, Japan's lack of national urgency led to excuses such as age or social status being used to exclude valuable contributors.

However, even among oceanographic experts, it was becoming increasingly clear that something serious was amiss. The discussions at Paramushir Island were now taking concrete shape. The key issue was that, in the Northern Hemisphere, "hot places are getting hotter, and cold places are getting colder."

Europe, naturally, is a cold region, situated at high latitudes. While it had benefited from warm ocean currents, it was now returning to temperatures more suited to its latitude—becoming simply another high-latitude region. This shift would likely be even more pronounced in inland areas.

If no people lived there, the concept of "hot places getting hotter and cold places getting colder" would remain a purely scientific issue. However, Europe is home to a total population of 500 million people. While Southern Europe might survive, those living in Northern, Central, and Eastern Europe would face two choices: flee south or perish.

Freezing to death would be one concern, but more pressing is the fact that agricultural production would no longer be able to sustain such a population. On top of that, Germany and the Soviet Union were currently engaged in a brutal war. How many more lives would be lost?

"What will happen to the Arctic Sea route?"

Matsuoka, fully aware that his question might seem out of place among the scientists, asked anyway.

The answer he received was completely unexpected.

"Sea ice will likely develop from Greenland to the Svalbard archipelago, across the Barents and Kara Seas, and make navigation impossible. The water temperature in the Arctic Ocean will drop significantly. The influence of warm currents will extend only as far as the Bering Sea and the Queen Elizabeth Islands, while other regions will experience cooling instead."

With the Atlantic warm currents no longer reaching the Arctic Ocean and increased precipitation, large amounts of freshwater from Scandinavian and Soviet rivers would flow in, forming low-salinity water that would freeze into sea ice. The concept of albedo was then brought up.

This idea, proposed by American astronomer George Bond, states that "white surfaces reflect more light, reducing the amount of solar energy absorbed."

The more sea ice forms, the higher the albedo (reflectivity), bouncing back more sunlight and accelerating cooling. Eventually, glaciers might cover Northern Europe. In fact, two-thirds of Great Britain was covered by glaciers during the last Ice Age. In stark contrast to the warming of the Far East, the western side of the Northern Hemisphere might enter an Ice Age.

This was the conclusion that European scientists reached after analyzing ocean temperature measurements and the disappearance of ocean current influences.

"But this situation won't last forever."

A dissenting voice came from Arthur Holmes, the geologist who proposed the mantle convection theory.

"North America was home to numerous volcanoes. Although the continent has disappeared, it has only submerged to a depth of 50 yards (about 45,7 meters). The mantle convection beneath is still active. This means that extensive orogenic activity may occur, which will create numerous volcanoes and new landmasses through eruptions. If that happens, warm currents similar to the Gulf Stream could reappear."

But when would that happen? Would the world enter an Ice Age in the meantime?

"Perhaps it won't take that long."

Norwegian Professor Ekman joined the discussion.

"Are you familiar with isostasy?"

Isostasy refers to the idea that the Earth's lighter crust is supported by the denser mantle beneath, and it rebounds upward when weight is removed.

This phenomenon has been observed in Northern Europe—when heavy glaciers existed, the crust sank deeper into the mantle. Once the glaciers melted and the weight was reduced, the crust rebounded upward. The Bothnian Bay, between Finland and Sweden, continues to rise at a rate of several millimeters per year due to this effect.

Based on this, the Rocky Mountains had been one of the heaviest parts of the North American continent. Now that they were gone, the area beneath them—now seabed—could eventually rise again due to isostasy and form new land. Additionally, Hudson Bay, in what was once Canada, had already been experiencing isostatic uplift long before the continent disappeared.

In other words, "North America may return, albeit in a different form. If that happens, the Gulf Stream could revive, and Europe might once again become a temperate land."

'How leisurely they think...'

Matsuoka, a bureaucrat concerned with logistics, thought to himself. While the scholars considered even tens of thousands of years a "brief moment" in geological terms, he was focused on what would happen to nations in the next few years at most. Neither orogenic activity nor isostatic rebound would restore North America within that timeframe. On the other hand, the spread of glaciers over Northern Europe might also take longer than anticipated. Though he might not witness large-scale changes in his lifetime, climate shifts severe enough to claim many lives were inevitable.

'Compared to that, the issue of the Arctic shipping route is trivial.'

At least now he had a conclusion. The Arctic Ocean would remain frozen over. With North America gone, if Europe were to engage in trade via the Arctic, it would have to look elsewhere, but since the Western Hemisphere would be locked in ice, that route was effectively closed. Furthermore, the Soviet Navy's Baltic Fleet, which the Navy feared—or perhaps anticipated—using the Arctic route to reach the Far East, would no longer pose a threat. In fact, there was even a possibility that the Baltic Sea itself could freeze over.

As Matsuoka was considering how to report his findings, a man who was not a scientist approached him.

"So, what course of action do you think Japan should take?"

The man in question could rightfully be considered a heavyweight in British politics. It was strange to see him in a place like this.

His name was Viscount Halifax, Edward Frederick Lindley Wood. Once the Foreign Secretary under Neville Chamberlain's cabinet, he had since been replaced by Lord Avon, but had still served as Foreign Secretary during the early months of Churchill's government in 1940. He was also a noble statesman who had previously served as Viceroy of India.

And now, this distinguished figure was asking a mere bureaucrat like Matsuoka about Japan's future course.

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The next chapter will be uploaded at 18:00.

- ほうこうおんち