I think I need to quote you again, which is weird because I think you wrote it:
It would be hundreds of millions of people. [to Europe]
It's still just your ass claiming those figures.
And another thing, you're talking about people fleeing from environmental disasters. Now I didn't wan't to tell you this, because it's like kicking someone who's down. But here goes. Last year, Sweden adopted a temporary law only adhering to the minimum requirements within the EU. Before, there were three categories for people in need of protection, refugees, "alternative needs" (punishment of death, torture, you name it [not really]), and "other needs". "Other needs" include chapter 4 §3 2 pt. of Utlänningslagen which provides protection for "people who can't return to their home country because of an environmental disaster". Sweden's new temporary law specifically excludes "other needs" through §4, which is valid until at least 2019. Remember, that law still fulfills the EU minimum, which makes your ENTIRE point moot, even if it wasn't just pulled out of your ass.
To summarize, a country within the EU can legally deport people with no other claims for asylum than environmental disasters if they so desire and have the necessary legislation for doing so. That's without breaking conventions (though to be fair I don't think that paragraph has been tested in court).
Learning is fun, eh?
So... you agree that we can deny people at the border? Sounds like the thing Hungary has been doing for a while.
And again, that is not excusing their other stuff. But we in more Western and Northern countries in the EU should not act like we have the moral high ground in this discussion and just tell the others what they should do.
See this is where you lose the plot. Hungary has been detaining people illegally. That means there are and always have been legal ways to detain people with no right to stay in your country. If a person at the border says "I want to apply for asylum!", Sweden won't deport you, and will instead subject you to the legal process of applying for asylum. Hungary does not, which makes your conclusion wrong and a bit embarrassing. Look up detention in Germany or any other country and compare it to the case where the European Court of Human Rights has condemned Hungary.
So yes, I agree, otherwise every country would've been involved in illegal activity since long before 2015. But no, it would only sound like something akin to Hungary to someone not up to date with the situation.