Say a superhuman destroys a 15KM meteorite and saves humanity from a mass extinction event. Debris and shockwave from the meteorite devastates the countries it was destroyed above and causes famine, death and general chaos across Western Europe. How will the world react to such an event?

It would probably cause a collapse of the economy in the rest of Europe and lead to a vulnerable position of Eastern Europe, in addition to Russia which exports plenty of gasoline from the western part of Europe. NATO and the EU would most likely dissolve into an American-Eastern European military agreement and a miniature EU for the remaining countries. Of course this would mean a massive refugee crisis of the Arabs who arrived there and millions upon millions of Western Europeans, likely the Arabs will go to Algeria or Morocco as East Europe would reject them, while most west Europeans would either immigrate outwards or to the nearby.