Nope. Nobody somehow knows this. This is just religious dogma of your religion. Many people BELIEVE this because their religious dogma commands the congregation to BELIEVE, without question, that Global Warming is KNOWN, and to BELIEVE this under the BELIEF that Global Warming is OBSERVED. Ergo, devoted worshipers such as yourself roam the earth preaching the "Bad News of the Word of Global Warming."
If you actually knew this, you would be able to post the rational basis thereof so that I could know this as well. However, just as it is in any religion, one is required to BELIEVE first such that no rational basis ever need be given. It's all part of the "You must BELIEVE without question."
Who is this "we" in your point #1 anyway? Don't worry, I'll answer that question for you. It is the Marxist "we." It is the pronoun used by dishonest people who wish to present their own unsupported opinions (or to preach their religions) as though they are absolute truths that are somehow already accepted by the entirety of humanity, and thus do not need to be supported in any way ... AND ... to insinuate that anyone who questions the unsupported opinions/dogma somehow bears the burden to support their rejection of the dogma.
Your statement should have read "I BELIEVE the earth is warming." That would have been an honest, truthful and accurate statement.
Did you write this with a straight face? Right off the bat, you knew that I, the person with whom you are discussing this matter, reject this item of your dogma. How can you say that no one doubts it?
Then we have to explore why you believe that anyone would believe that you somehow speak for everyone, or why you believe you can read everyone's mind? Let's jump to the chase. Can you and I both agree that you do not speak for everyone and that you cannot read anyone's mind?
This is a stupid statement. There is no such substance as greenhouse gas. All substances absorb IR.
Exactly. For the same reason, we know that energy does not simply come into existence from nothing. There is no matter anywhere in the universe that somehow spontaneously increases in temperature without additional thermal energy, and thermal energy never pops into existence out of nothing.