My friend says global warming is caused by planet X, when will planet X comes, and what will happen?

A suspected planet that is several times further away than Pluto effecting Earth weather?

I don't think so.

Is your friend a renowned authority on the subject?

Friend is messed up. There is no planet X. That is a myth.

Ask your friend when.

They havent seen this Planet X yet ?

I think it is more likely that your friend is from Planet X.

Ignore your friend like you should ignore anti science right wingers

Your friend is wrong.

Physically, mathematically, statistically, evidentially, and experimentally wrong. Which is about as wrong as any single person can be!

Planet x will arrive tomorrow morning at rush hour.

You may need to go to work a little early tomorrow because the forecast is for a interglacial period and uncommonly high temperatures.

It will be over by lunch time though.

So by quitting time it will be as if nothing has happened.

Is your friend called Solar Wind?