, which have helped to feed [closed]

Question

Satellites track weather patterns and measure the effectiveness of farming methods and innovations in agriculture, which have helped to feed millions more than we could have dreamed possible before the space age. (from Space 2.0 How Private Spaceflight, a Resurgent NASA, and International Partners are Creating a New Space Age by Rod Pyle)

1. What is the antecedent of the bolded "which"? Considering "have helped" after "which", the antecedent is plural. Is it two VPs: "track weather patterns" and "measure the effectiveness of farming methods and innovations in agriculture"? Or, is it just "farming methods and innovations in agriculture"? Or, is it the previous clause as a whole?
2. If I change "could have dreamed" into "could dream", does it change the meaning of the sentence? What's the difference between using "could have dreamed" and "could dream" in terms of meaning, especially concerning referred time?

Answer 1

Q1

My initial reading was that the antecedent is "farming methods and innovations in agriculture". The antecedent should be a plural noun phrase, since verbs don't help feed people. And by default, the antecedent is usually the closest preceding noun phrase that makes sense.

However, because they compare this with "before the space age", they may have meant that using satellites to track these things has helped feed millions of people. If this was the intent, I think they worded it poorly.

Instead, I think they're simply conflating "the space age" with the age of modern farming technology. The innovations happened in parallel, and now we're using satellites both to improve farming (by improving weather tracking and forecasting) and to measure the effectiveness of all these technologies.

Q2

I don't think there's any significant difference between "could dream" and "could have dreamed" in this context. The qualifier "before the space age" sets it in the past, so the past tense verb is redundant. "could have dreamed" feels more idiomatic to me, though.

Answer 2

Both

• Satellites track weather patterns, which has helped to feed millions more than we could have dreamed possible before the space age.

and

• Satellites measure the effectiveness of farming methods and innovations in agriculture, which have helped to feed millions more than we could have dreamed possible before the space age.

are grammatical.

The first sentence has the entire clause, '[The fact that] [s]atellites track weather patterns' as the antecedent of 'which', which is standard.

The second sentence has the coordinate noun phrase 'farming methods and innovations in agriculture' as antecedent for 'which', which is grammatically fine, but semantically/logically awkward ... one would expect say

• Satellites measure the effectiveness of farming methods and innovations in agriculture, which have been shown to have helped to feed millions more than we could have dreamed possible before the space age.

But worse is

• Satellites track weather patterns and measure the effectiveness of farming methods and innovations in agriculture, which have helped to feed millions more than we could have dreamed possible before the space age.

which can only realistically be parsed as twinning a main clause and a (coordinate) noun phrase as the antecedent, which is unacceptable lack of parallelism (arguably zeugma).

...............

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