4 degrees by 2100 really seems like what we’re heading for. The Trump admin might have been trolling, but their estimates say 7c.

I thought 7°C would be insane, so I googled it, and found this article in the Washington post about it which says:

A rise of seven degrees Fahrenheit, or about four degrees Celsius

So you were right with the 4°C. It's just confusing that they use two different ways to measure it.