As a Brazilian I say that this is just plain stupid in 3 different levels:
1) World diplomacy is or should be ruled by the principle of Westphalian Sovereignty: the idea that each nation is free to conduct its internal affairs as it pleases.
2) Brazil is the 5th largest country in the world, one of the 10 largest economies and the 8th biggest population. Who has the resources to spare and fight a war with Brazil?
3) During the 90's the main argument by farmers and loggers for deforesting the Amazon was exactly arguments like yours. Back then this bullshit you say was called "internacionalização da Amazônia" and those parasites argument was: "we need to occupy the Amazon before the gringos do it". So, basically, when you say this bullshit you are supplying arguments to the enemy.
Please, stop this bullshit. It is dangerous. It makes the fight of Brazilian environmentalists even harder.
And I'm not arguing for war.
No, the express is stupid. Amazon is an old forest and consume almost all oxygen it produces. Oxygen come mostly from algae in the ocean.
Amazon is important for climate control and biodiversity.
I wonder, doesn't most oxygen come from those trees? I've read the expression "lung of the planet". Essentially it seems it's a matter of survival.
Although increased CO2 concentration might also accelerate the growth of trees, so I don't really know.