[Lightscreen]
[The Tang Dynasty says it is not done yet showing off its ridiculously stacked hand of starting resources. Not by a long shot.
That warm and delightfully humid climate did not just raise the temperature by 2 degrees. It completely transformed the water systems along the middle and lower reaches of the Yellow River. Rainfall was abundant, rivers were brimming, and agricultural irrigation reached levels of effortless efficiency. On top of that, inland fisheries were so rich with freshwater life that food was basically jumping out of the water and into people's cooking pots.
When winters get shorter and milder, the growing season for crops automatically gets longer. You do not even need to dive into dense, boring academic papers to prove this historical fact. You can literally track it by reading popular poetry from the Tang and Song eras.
During the Tang Dynasty, farmers were out in the fields harvesting their winter wheat in the 4th lunar month, which translates to late April or early May. By the time the Song Dynasty rolled around, that exact same wheat harvest had been pushed back to the 5th lunar month, landing somewhere in late May or June.
That is a full month of agricultural delay caused entirely by the cooling climate.
Furthermore, the earliest surviving historical records of double-cropping, specifically rotating rice and wheat on the exact same plot of land within a single calendar year, originate directly from the Tang Dynasty. While this advanced farming technique might not have been implemented across every single village in the empire, it undeniably provided a huge boost to the overall national grain output.
So here is the summary. A temperature shift of just 2 degrees Celsius produced changes that were nothing short of overwhelming.
It gifted the Tang Dynasty with the largest total area of prime arable land in Chinese history, a delightfully comfortable living environment, and an insane abundance of grain and natural resources. It was this exact ecological lottery win that built the legendary, unstoppable, golden age of the Great Tang.
However, because they were sitting on such a huge pile of natural wealth, the Tang Dynasty also holds the absolute record for the most reckless, wildly wasteful destruction of natural resources in human history.]
Back in the Three Kingdoms era, inside the command office in ancient Chang'an, Liu Bei was staring blankly at the window.
He leaned forward a bit, trying to get a better look through the clear glass pane that someone had installed in the wooden frame. This building used to belong to a high-ranking imperial general. One of the few fancy structures in old Chang'an that managed to survive the crazy fires from the warlord era without turning into charcoal. After some quick repairs and basic touch-ups, the place still gave off a faint vibe of its old glory days.
Through that polished glass, Liu Bei looked out into the courtyard. His eyes stopped at a big old tree standing near the stone walkway. The leaves on that tree were surprisingly small and thin. The fresh green buds had just barely managed to poke their way out of the bark.
It was the end of the 4th month. And yet stepping outside still felt like walking straight into a cold hug that had not let go of the world yet.
But in the Tang Dynasty, at this exact same point in the calendar, the wheat was already harvested.
Liu Bei sat there with that thought for a long while.
He realized he did not envy the Tang's military glory anymore. He did not envy their poets, their fancy palaces, or their endless silk roads. He did not care about their legendary cavalry, their famous generals, or their heavy iron armor that probably weighed as much as a small horse.
He just wanted their weather.
Just a few minutes earlier, after finishing his rapid transcription of the climate chart, Zhuge Liang had walked over and broken down the core meaning of the graph for his lord in simple terms. The message was blunt. Over the next century, the climate in their timeline would plunge into an irreversible prolonged deep freeze. The natural environment across the northern territories would only become harsher, drier, and more brutal with every generation.
Zhuge Liang had also offered a quiet suggestion on top of that. He said the regime needed to develop the south early, laying the groundwork to explore and cultivate the lush undeveloped southern lands far earlier than originally planned. Simultaneously, they needed to build strong armies and strong cities along the Yellow River, to make northern peoples think twice before testing the borders.
It was a really good plan. A practical plan. But hearing that the Tang could grow rice north of the Yellow River made Liu Bei want to lie down and stare at the ceiling for an hour.
He could not even imagine that. Cultivating rice in the north. Growing where frost still crept into the soil in his own time. This damn broken era...
Beside him, Zhuge Liang was far too busy to indulge in idle melancholy. He hunched over his desk, his brush flying across long strips of wooden slips as he aggressively transcribed every single historical snippet regarding the ancient geographical text Man Shu, the Book of Barbarians.
Pang Tong and Fa Zheng let out a long breath at almost the same time. After spending the last few months knee-deep in real governance work, neither of them could pretend to be clueless about agriculture anymore.
"This advanced method of double-cropping, harvesting both rice and wheat from a single field in one year," Pang Tong said, chewing on the words like they were a piece of tough jerky. "The junior called it an advanced agricultural technique. That means people in the future still lean on this exact system pretty heavily, doesn't it?"
By now, his ears were practically tuned to the way people from the future talked. Two little words were enough to set off alarm bells in his head.
Fa Zheng had spent years in Hanzhong. The sun there had darkened his skin by a couple of shades, and in return, his understanding of farming had deepened by just about the same amount.
"The junior managed to wrap the whole concept up using the proper term double-cropping system," Fa Zheng added, his sharp eyes lighting up like a scholar who just found a hidden scroll in the library. "That alone proves this method is not just about sticking rice and wheat together."
"Think about it. For something to be officially labeled as a system, people have to be using it all over the place. We know the climate in the future is nowhere near as warm as the glory days of the Tang Dynasty. If future generations can pull off double-cropping without that natural advantage, then the real key is human management and technique. Not just sitting around hoping for good weather."
He paused for a second, the gears in his head clearly still spinning. "We should set aside several experimental plots right here in Guanzhong. Run some controlled tests. See if rotating winter wheat with summer soybeans or other crops can actually squeeze out two full harvests in one year."
Zhuge Liang looked up with an approving smile. He gave a slow nod.
"Then I will leave this in your hands, Xiaozhi."
The economic potential of a double-cropping system was obvious to anyone with half a brain. The problem was, the Han Dynasty era simply did not have the fancy biological theories and chemical knowledge of the modern world. They did not understand soil nitrogen levels, crop genetics, or how plants absorbed microscopic nutrients from the ground.
Without those futuristic shortcuts, expanding double-cropping beyond the usual rice and wheat rotation meant they had to walk the old path. The most tedious method known to man. Trial, error, and a whole lot of patient manual observation.
Since Fa Zheng could see the core of the problem this clearly, the assignment fit him naturally.
Fa Zheng did not object in the slightest. If anything, his eyes lit up with genuine excitement.
Truth be told, leaving the isolated valleys of Hanzhong to help Lord Liu Bei reclaim, rebuild, and develop Guanzhong was exactly the dream Fa Zheng had been chasing all along.
He was a native of Youfufeng. A true son of the Three Qin region, blood and bone. Coming back to his ancestral homeland in a high position, trusted with the task of breathing new life into the soil of his own ancestors, that was the ultimate badge of success.
How could he possibly see that kind of honorable work as exhausting?
With tasks distributed, Zhuge Liang allowed himself a short moment to think ahead. His mind already leaping years into the future.
He could easily piece together how the ecological disaster of the Tang Dynasty had unfolded.
A climate this generous naturally made plant life grow at an absurd speed. Trees shot up fast. Rivers ran deep. Crops practically burst out of the earth on their own. And in the early Tang, the nation was just crawling out of a horrific era of brutal civil war. The population was thin. Fewer people meant fewer eyes watching the treeline.
Under those specific conditions, it was almost impossible for Tang officials to care about forest conservation or timber management.
To them, those vast untouched forests stretching all the way to the horizon probably looked endless. Like a pantry that would never run empty. So they chopped down ancient trees for grand palaces. Chopped more down for heating. And chopped even more down for industrial iron foundries without losing a single night of sleep.
Then the climate shifted. And the consequences of all that carelessness came knocking to collect the debt.
The ancestors chop down the trees, and the descendants suffer the consequences. Zhuge Liang agreed wholeheartedly with that modern proverb.
Looking at the historical timeline, the Tang Dynasty did not even have to wait for future generations to feel the pain.
The environmental bill landed right on their own doorstep.
---
In the heated chambers of Bianjing, the sibling violence had finally calmed down.
Zhao Guangyi sat with his face twisted in discomfort, gently rubbing his bruised right shoulder. He lowered himself into a chair like a man sitting on a suspicious-looking stool that might collapse at any moment.
Zhao Kuangyin was still breathing heavily. The dark rage on the Emperor's face had not fully gone away. But since his complexion was naturally dark and weather-beaten, nobody in the room could tell exactly how angry he still was.
Listening to the Light Screen's summary, Zhao Kuangyin felt the exact same jealousy Liu Bei was feeling. Pure undiluted longing for a climate that belonged to someone else's dynasty.
He knew the gap between Song and Tang in terms of arable land. Everyone in that room knew it. What he had not expected was this. He had simply never imagined that behind a simple abstract phrase like the weather got cold, there lay such a terrifying and tangled web of geopolitical consequences.
Naturally, just like Liu Bei, Zhao Kuangyin could not help but daydream. What if his Song Dynasty had been blessed with that exact same warm and rain-heavy climate? What if they could grow rice all the way up near the northern borders? What if...
Then he saw Zhao Pu's face.
The chancellor's expression was more bitter than his own.
He looked like he had just swallowed a gallon of spoiled milk. His miserable expression was way more obvious than Zhao Kuangyin's dark scowl. Because Zhao Pu had a relatively fair and pale complexion, every twitch of terror and despair on his face was visible in high definition.
"Our climate might not be as wonderfully warm as the Tang Dynasty," Zhao Kuangyin began, trying to offer a bit of rational comfort. "But surely our agricultural foundation is still..."
Zhao Kuangyin did not finish the sentence. Zhao Pu shook his head and delivered two words that landed like a brick through a window.
"The Yellow River."
Zhao Kuangyin froze.
He had been so busy envying the Tang Dynasty's agricultural lottery win, he had completely overlooked another catastrophic legacy the Tang had left behind.
The Yellow River.
The Light Screen had said it so simply. But now, turning the phrase over in his mind, Zhao Kuangyin felt his back go cold.
Treating the symptoms, but never the root cause.
The meaning was plain. And the implication behind it was that for the entire duration of the Song Dynasty, their administration would be forced into a permanent wallet-draining war against the violent and unpredictable flooding of the Yellow River.
Oh wait. Zhao Kuangyin suddenly remembered a piece of information the screen had casually dropped in a previous episode.
The Southern Song Dynasty had eventually lost control of the northern territories entirely. Which meant the Yellow River basin was forfeited to foreign invaders anyway.
Zhao Kuangyin's already dark face instantly turned blacker than the bottom of an ancient iron cooking pot.
The reason for his sudden existential dread was simple.
Their imperial capital, the city of Bianjing, was sitting right on the banks of the Yellow River.
---
If Zhao Kuangyin was paralyzed by existential dread, Li Shimin of the Tang Dynasty was experiencing a state of pure offended rage.
Li Shimin could not accept this. He simply could not.
Just a short while ago, Li Shimin had been sitting comfortably on his imperial throne, openly laughing at the weak and cowardly Song. He had openly expressed his disdain for their pathetic military record, even declaring that the Song Dynasty was completely unworthy of being considered the successor to his Great Tang.
And now it turned out that part of the Song's weakness was the Tang's fault?
This was unacceptable.
"Pass my imperial decree immediately!" Li Shimin suddenly roared. "Starting tomorrow morning, the Ministry of Works will dispatch survey teams to every single corner of the empire! Map out every coal mine, every mineral vein, and every outcrop within the borders of the Great Tang!"
The future's claims might contain some exaggeration. But with the climate chart as backing, Li Shimin understood the shape of the problem clearly enough. This warm window would last 200 years at most. The cold that followed would not bend to the will of emperors or heavenly khans.
The Tang's history was already shifting under his hands. Perhaps the dynasty would gain another century. Perhaps some unforeseen disaster would cut it short. Either way, the people in this room owed something to the generations that came after them.
Dynasties changed. Emperors changed. But the people who lived and died on this land remained. They were always the ones who paid the bill.
He refused to let his legacy be that of a reckless and short-sighted ancestor who burned down the house just to keep himself warm for a single night.
"Fang Xuanling!" Li Shimin turned his sharp gaze toward his head administrator.
"Your servant is here, Your Majesty!" Fang Xuanling immediately stepped forward.
"Draft a strict and comprehensive forestry conservation law by the end of the week," Li Shimin ordered, his voice cold and resolute. "Clear-cutting ancient forests along the upper reaches of the Yellow River is hereby strictly prohibited. Anyone caught illegally felling timber for private commercial gain will have their entire family property confiscated and be exiled to the far southern borders!"
Li Shimin paced back and forth, his mind working at full speed. "We will push the industrial sector toward coal consumption immediately. If future generations could smelt iron and heat their homes using coal dug from the earth, then my Tang Dynasty will learn to do the exact same thing today!"
Fang Xuanling's eyes shone with deep admiration.
He bowed even lower, his forehead almost touching the floor. "Your Majesty's vision extends across a thousand generations. It is the ultimate blessing of the empire!"
Beside him, Du Ruhui was already writing down the Emperor's verbal decrees on an official scroll, his mind calculating the economic shifts this coal initiative would require.
Li Shimin stopped pacing. He turned back toward the Light Screen, his hands clasped tightly behind his back, his posture straight as an iron rod.
Let future generations judge him however they wished. But as long as he, Li Shimin, breathed air, he would ensure that the foundation he laid for his civilization was as solid as iron.
And Li Shimin, for all his ambition, had no intention of leaving them a tab he could not cover.