75. Simulation

The day after hearing Maria’s strict stance on immigration.

The light cruiser Klein, which had transported Ichijō and the others to Earth, returned in a swift turnaround to Agirakana.

I considered boarding the Klein immediately and heading back to Earth—then realized how blatantly unprofessional that would be. According to Maria’s judgment, such actions did not constitute a “forced march,” and maintenance on the vessel was routinely performed as standard procedure, so no issues arose. Still, that did not justify exploiting the lower ranks. In the end, we decided to depart for Earth the following day.

And the next day.

Accompanied by Maria, we boarded the Klein and arrived at the Agirakana Embassy in Tokyo via the hyperlane gate after a six-hour journey—well past nine o’clock in the evening.

The members of the Secretary's Office, starting with Ain who had come out onto the rooftop to greet us, were quickly dismissed. I headed straight to my quarters on the ninth floor inside the Embassy, took a shower, and decided to rest for the night. Ichijō said she’d be late tonight—duly engaged in her role as a serious businesswoman. One could expect nothing less from someone who’d been ranked in the top ten of Favers’ “Most Influential People in the World” for years running.

Next morning.

Japan was just past the end of a long holiday week, a Thursday. I descended to the office on the eighth floor, exchanged morning greetings, and then said,

“…Ain, given this situation, could you run a simulation—assuming we inform all nations that Earth will certainly be destroyed in two hundred and some decades—on what might happen?”

"We already have models built for responses to such sociological impacts, and empirical observations have been conducted as well—so I believe we can simulate it with sufficient accuracy. I should have it ready by after lunch."

"Then I'll leave it to you."

Somehow, despite the convoluted explanation, it seemed clear enough: they could estimate the effects of announcing Earth’s destruction with considerable precision.

The Embassy’s automated cookers, capable of easily accessing a wide variety of ingredients, offer a menu as diverse as the cultures they represent—Agirakana One, to be precise. Japanese, Western, and Chinese fare are all on hand, yet Japanese cuisine remains the most popular by far. Among the ground troops stationed at the Embassy, some do favor the higher-calorie Chinese and Western dishes, but since everything is buffet-style, there’s currently a kind of trend toward consuming large quantities of low-calorie Japanese food. As for such culinary practices, data on nearly all menus worldwide have reportedly been acquired, so all that remains is to secure the ingredients—after which, physical replication seems feasible. Currently limited to food, the system could, if desired, imitate traditional crafts as well.

After sharing lunch in the break room, I was sipping the instant coffee someone had prepared for me at my desk in the Office when Ain arrived.

“The simulation results from this morning’s orders from the Captain are ready. Please come to the small conference room. I’d also like to request the presence of Major Maria.”

We moved from the Office to the adjacent small conference room, where we would hear Ain’s briefing. On the way, we passed Ichijō, who had just come up from the eighth floor; a brief greeting was exchanged before parting, and then I sat beside Maria in the small conference room, listening to Ain’s explanation.

“This is the simulation result of what happens if, at this moment, we were to notify the governments of all nations—through the Japanese Government—that Earth will be destroyed in two hundred and thirty years. The notification includes our assessment of Zeno, along with recorded footage of Agirakana’s combat history with Zeno over the past several years.”

First, what stands out is the declining birthrate in advanced nations. For the past few years, birthrates in these countries have hovered around 1.7, and since most advanced nations enforce strict immigration controls, their populations are gradually shrinking.

Under these conditions, should we issue the warning mentioned earlier, it is projected that the birthrate would plummet to 0.2 within the next twenty years, continuing a slow decline thereafter, and fall below 0.1 within fifty years.

Meanwhile, birthrates in non-advanced nations will also continue to decrease, though at a much more gradual pace compared to advanced countries—remaining above 2.0 for another fifty years, yet the rate of decline will steadily accelerate, eventually dropping below 0.2 by the hundred-year mark.

Of course, during this period, the economies of advanced nations collapse, and productivity across all industries plummets. In countries with low food self-sufficiency rates, mass starvation occurs early on. At the same time, social instability escalates—major crimes centered on looting surge, and suicide rates spike. Regional conflicts are also expected to intensify.

By thirty years in, maintaining social infrastructure becomes increasingly difficult; by fifty years, nearly all modern infrastructure built in the recent past has ceased to function, accelerating the regression of civilization.

Due to these cumulative factors, it is estimated that Earth's population, one hundred years after the warning, will have declined from the current 8.5 billion to just 500 million—approximately the estimated global population around the year 1500.

This simulation assumes no active support from Agirakana to Earth's nations.

I cannot say what conclusion the captain will draw from these simulation results, but at my level of assessment, the current warnings directed at Earth’s national governments seem extremely hazardous.

Precisely a post-apocalyptic scenario. A world resembling hell was anticipated. Even I had not imagined it could reach such extremes.

So, what now?

From eight point five billion down to five hundred million—eight point five billion corresponds roughly to the estimated global population around 2035. Five hundred million is not the product of any particularly intricate calculation, merely a rough estimate.