There are many ocean currents that take warm water up to London, thus warming the air there.
The higher the population the more water is consumed. the Aquifer is depleted.
America is an example of a multicultural country or a "melting pot"; some things you'll see in the states are different cultural food for example Taco Bell has Mexican food, Panda Express has Chinese food, and a hotpot place would serve Korean food. You'd also most likely find multilingual people