がなかったら、我々は

if there were no ..., we would

→ が
phrase Rare #39,915
if there were no ..., we would This is a sentence pattern meaning that without something, “we” would be unable to do something or survive. 我々 is a formal or written way to say “we.”
JA: 水がなかったら、我々は生きられないだろう。
EN: If there were no water, we would not be able to survive.

もし太陽がなかったら、我々は生きられないだろう

If there were no sun, we wouldn’t be able to live.

君の助けがなかったら、我々は計画を実行することはできないだろう

Without your help, we wouldn't be able to carry out the plan.

もし植物がなかったら、我々は生きていけないだろう

If there were no plants, we wouldn't be able to survive.