These problems are likely caused by urbanization.

air pollution
declining birth rate
forest overgrowth
housing shortages
overcrowding
volcanic eruptions
water pollution
water shortages

Air pollution, housing overgrowth, overcrowding, water pollution, and water shortage

Europe needs to build a trump-like wall that will spread across europe making it impossible for migrants to cross they need to spread pig guts all over this wall so the muslims will never consider crossing into europe..you might be asking "can't they just fly over with planes? " well yes they can so we will install thaad missile protections system to shoot down any aircraft that violates europe's air fourth would be to start a fourth reich in germany.. last but not least.. make europe great again!