Bolivian Army Ending: Sandman and the rest of the Delta team (except Frost, who is absent for some reason) note possibly resolved by the DLC Spec Ops Mission Black Ice, where Frost plants a DSM in an unspecified setting with the same model as the mine in Down the Rabbit Hole to initiate a self-destruct sequence in said mine stay behind to allow the others to escape, fending off a large amount of soldiers.
London is devastated in the chemical attacks and most of the European capitals suffered a similar fate.
Bittersweet Ending: Makarov has finally paid for what he's done and the war's come to an end, but nearly everyone who worked to get that far, now including Soap, Yuri, and three fourths of Team Metal, are dead, and the world still had to fight a war in which millions of people died, essentially, for nothing.
Modern Warfare 2 Remastered does more-or-less the same thing during No Russian, bringing Yuri's failed attempt at stopping the massacre. Both games' remasters call back to this: the Call of Duty 4 remaster places Makarov and Yuri in the jeep they were in during the MW3 flashback - where you can kill Makarov to get the " Time Paradox" achievement, but get a game over for friendly fire if you shoot Yuri. Makarov himself gets this treatment for most of that scene as well, showing him as the driver that got Zakhaev safely away after he was shot, and as the one who personally detonated Al-Asad's nuke. Yuri even managed to crawl up to the main terminal and was steps behind Makarov, Private Allen et al., trying to stop them before passing out from his injuries (although he couldn't aim for shit in the state he was in anyways, so it's unlikely he could have done anything).
Been There, Shaped History: It turns out that Yuri was there when Zakhaev's arm was shot off, watched the nuke go off in the first Modern Warfare, and was supposed to join Makarov in the "No Russian" airport massacre, but Makarov gut-shot him in the underground parking lot after Yuri had a change of heart and attempted to warn the authorities.