pronoun's reference

[ian2]

Kaifeng, an ancient city along the mud-clogged Yellow River, was by far the most important place in the world in 1000. And if you've never heard of it, that's a useful warning for Americans - as the Chinese headline above puts it, in a language of the future that many more Americans should start learning, "glory is as ephemeral as smoke and clouds." (From the New York Times)

Does the pronoun "that" refer to the previous clause, that is, "you have never heard of it"? Why is "never heard of it" is a warning for Americans, or in what way is that a warning?

Thanks.

[Casiopea]

The link is here: China, the World's Capital - New York Times

[Casiopea]

Here's what I get:

Kaifeng used to be the most important place in the world, as is New York today. And if New Yorkers have never heard of Kaifeng, that's (having never heard of Kaifeng) a useful warning for Americans, because history might repeat itself: New York, like Kaifeng, might not be the most important city in the future.

Does that help?

[ian2]

Here's what I get:

Kaifeng used to be the most important place in the world, as is New York today. And if New Yorkers have never heard of Kaifeng, that's (having never heard of Kaifeng) a useful warning for Americans, because history might repeat itself: New York, like Kaifeng, might not be the most important city in the future.

Does that help?

Thanks. Is there another way to explain: the fact that you have never heard of Kaifeng is a useful warning sign, because "never heard" implies you are narrow-minded, only paying attention to your own business, and that is a warning sign?

[Casiopea]

Have never heard of is another way of saying aren't aware of. The author is saying Kaifeng's role as the most important city in the world in the year 1000 has long since been forgotten, and so New Yorkers should pay heed: their city is surely destined to follow the same fate when another city becomes the economic hub of the world.

[Barb_D]

I do NOT take "never heard of" to mean the person who has not heard of it is narrow minded at all. All the time people say "I've never heard of that - please tell me more!"

Cas's interpretatino makes complete sense to me - you've never heard of that city, but be warned, in a 1000 years, people may never have heard of yours.

(By the way, I wonder what the residents of Constantinople in the year 1000 would say about the claim?)

[a writer, not a teacher]

[Casiopea]

(By the way, I wonder what the residents of Constantinople in the year 1000 would say about the claim?)

[a writer, not a teacher]

I take it you also found fault with the author's argument. (I was thinking Rome, actually.)

[ian2]

I take it you also found fault with the author's argument. (I was thinking Rome, actually.)

The reason I was not sure about "never heard of" is I find it hard to logically link "never ..." with the following "glory is as ephemeral as smoke and clouds". I feel there is a small gap between the two parts. "Never heard of it, so that shows "glory is ....smoke .."?

Thanks again for your great answer.