What will be the consequence for the environment if we allow 1 billion people from Africa and MidleEast into the west?

What do you mean 'allow'?

How will you stop a billion people?

Other than killing them.

It would be very bad. That would be extremely uncontrollable. There would be scarcity of water, shelter and food that will ultimately result in rise in poverty rates. The Western world itself will get as worse as Africa & Middle East. Only dying skeletons, dead bodies will be found everywhere on road.

The West would be an Islamic country. White rice will die out. Muslim men will convert their women into Islam but still they die of hunger. Maybe some are Christians but theit condition will be same. Only death, destruction and war will happen. That's terrible to imagine that!

What difference does it make to the world where people live? Humans will always rape the environment for their own use.

Lowering of wages because of an increase in cheap labour. Increase in house prices and less availability of social housing, pressure on healthcare, longer waiting lists, larger school classroom numbers, lower qualification level because of this, increase in crime, increased policing, more street people, death of cities due to lower wages but increased rent prices - less cash in the economy, falling food standards, increased death rate in the population because of people eating unsafe cheap food and reduced medical facilities, political uprising against authority demanding more jobs, authority backlash then - Civil War.

This question keeps being asked and answered.

The answer is - minimal. Because all that's happening is the location of people is changing.

Then I feel very sorry for the people in "the west".

The environment is already under pressure. Why add more people to trash it.

If this happens, nature will suffer, especially in and around major cities where immigrants must congregate in order to survive financially. Because immigrants are under stress to survive in a new nation, they will be less interested in environmental causes than people with generations of family history in that nation. This would affect elections of lawmakers who might not be interested in passing laws favoring regulations to save the environment.