I feel like downplaying 1.8 degrees C of performance is a weird choice in the article.
1.8 degrees C is a huge temperature change in biology. Human bodies keep thermal equilibrium in a margin smaller then that.
Also: Freezing right away when you stop moving at 8k altitude? I was just skiing at 11k and it never even crossed my mind.
Also weird phrasing: "a staggering 1.8 degrees" begs the reader to think of it as a large number (which in fact it is, as you point out) yet their intent seems to be, ironically and paradoxically, to diminish it.