This is how it is, Yang Ping roughly understood why with the geography knowledge he acquired during middle school.
"This is also the reason why advanced civilization did not develop in ancient North America, because ancient times were an agrarian society. People didn't have the capability to resist cold waves; hard-grown crops could be completely destroyed by a sudden cold wave, making food production unstable. Naturally, they could not nurture an advanced civilization. But an industrial society is different; various technologies can be used to compensate for natural climate deficiencies."
