Edit: after reading some of the answers, if i was to rebuild a society, would it be more effective for a society without the needs for religious daily rituals etc... Also would it be better if it was replaced with moral ethics and critical thinking
are caused by religious matters
They are justified by (or blamed on) religious matters, that's a bit different thing.
People are warring/killing/hating each other for a plenty of time now, having following as essentional "excuses":
- You don't deserve you possess. (pursuit of justice)
- I need that, what you possess to survive. (self-preservation)
- You're not like me and my group. (social identity)
Religion comes from third group, which also have a plenty of other examples over the course of history (+ today):
"You're not like me (and I hate you), because of": skin color, religion, gender,sexual orientation, your general lifestyle, your attitude towards something (includes politics, football teams, being a convinced criminal/law-abiding-citizen, etc.etc.), and many more other things (even just something as silly as "what part of Great Britain do you come from" or "how much do you earn").
If you paint all the people green, make them straight and give them the equal salary, they will just start grouping by teeth length, eye color and favorite season.
So no, you won't cure humanity and stop the violence purely by removing religion - people will always find a way to team up and justify their hate towards "aliens".
I tried to keep this answer as short as I could. There actually a lot more to say about subject. Intraspecific violence of humans is a pretty complex social thing and just removing one factor won't help much.
A willing to "remove religion" can be reasoned in some other ways (like developing critical thinking or some other stuff), so I've answered about "peaceful" part only (the answer is "NO").
Other parts of your question ("effeciency/effectiveness without religion") are a raw fuel for holy wars, since any religious person's answer would be "Yes, except mine", or simple "No" (assuming the person is logical), while non-religious answers will vary, since religion is a pretty powerfull tool of both control (for church/govt.) and of staying sane / handling difficult life situations in this senseless cruel world (for a lot of people), which can't be thrown away carelessly.
Religion was a fundamental building block to human history and forms the framework for politics.
Philosophically speaking, it might be possible to create a civilisation that doesn't rely on religion - Plato's Republic is a prime example. However, this isn't likely to happen as religion continues to underpin our lives.
I dont think so.
Most of the wars today arent really caused by religion, but rather by greed.
Humans will always question their existence, no matter what, therefore religion would exist whenever a intelligent species forms. The bad thing about religion is, that the leaders of certain religious communities were/are cruel and greedy. They exploit the naivety of the people.
For example: There is a church in Brazil where you can only enter if you donate 20 or 30 percent of your annual sallary to the church. While people think they're donating to "god's house", they are actually just giving the money to the rich leaders of that church.
Of course, there were wars caused by religion especially in the middle ages, but the time of that is over.