It should be compared. The other wording is also a little strange, so the text doesn't feel natural to me.

I just worry when I see new skyscrapers or overly designed huge constructions, 1 - we don’t usually use “construction” as a noun like this unless you mean —> a construction project underway/in progress (notice here it is being used as an adjective, a more common use) Instead say something like: buildings, or towers, or construction projects (if currently underway) comparing to the amount of things that I can conserve 2 - compared: this because when speaking in English, using multiple verbs in different forms requires also that, inherently, the construction makes sense even without the information in between: “I challenged him, comparing and contrasting his argument and mine” would be an example because: “I challenge,” How? “I compare, I contrast,” and then I give a direct object of what I compare and contrast. Your use, however, is: “I worry,” How? “I compare” Which doesn’t really makes sense. To avoid this problem, in English we would reintroduce the subject “I,” and use a conjunction to say something like: “I worry when I compare…” or “I worry because I compare…” This expresses that your worry is a result of the thought process that follows: how much you could conserve. and there are so many serious problems to be taken care of in the world. In the above text, l've been told that the 'comparing' should be 'compared,' but I don’t understand why it is like so 3 - instead of saying “like so,” usually we say “like that,” however, in a sentence like this, we would simply say: “I don’t understand” or “I don’t understand why,” with nothing afterward If you feel absolutely compelled to express the idea of “like so” then I would suggest: “I don’t understand why we say it like that..” “Like so” is less commonly used, in general, and even when used, it is usually used to demonstrate an example of performing a task: “How do I turn on the TV?” “Like so.” (Person demonstrates which button to press) (More common): “Like this!”