Nuclear Winter is what would happen, in the long term places might end up becoming deserts because vegetation and wildlife are wiped out.

Well, deserts exist already, and if the world ends, then they will be post apocalyptic deserts. Nuclear weapons are not going to cause jungles to sprout up overnight in any of these arid locations, be it the Mojave, the Gobi, or what have you. So by default, these deserts are guaranteed to be post apocalyptic and will be so the very second the world "ends." A nuclear winter might occur, but an eventually is slower on the draw than instantaneously.

Well realistically speaking the weather wouldn't even matter, as if the same volume of bombs as the ones in Fallout dropped in our world the radioactive fallout alone would probably kill most if not all animal life, even if they survived the initial explosion.

But to answer your question I think a nuclear winter would be the most likely as all the fallout and general guff from the bombs would probably block the sun for a good while, lowering the temperature in a way a bit similar to a volcano eruption. But I could just be talking out my ass

Both probably. Cold climates actually reduce overall precipitation, so we will see the expansion of deserts.

However, human activity is already causing desertification. The interuption of harmful agricultural practices, land clearing, and over grazing could allow areas to recover. But the ecological damage will also disrupt ecosystems, possibly creating more deserts.

Current climate models indicate both are likely outcomes. The geologic evidence for Nuclear Winter is most notably the co-occurrence of large amounts of sunlight blocking elements into the atmosphere after major volcanic or meteor events and mini to major ice ages. So the nuclear winter part is pretty much common ground for most climate scientists.

Desertification is strongly associated with glaciation. For example the Sahara was once a thriving ecosystem, but the more likely hypotheses are that glaciation weakened the North african monsoons resulting in the desert wasteland we see today.

So after a nuclear winter there would likely be deserts were none existed before, but by the same token there would be heavier rainfalls where none existed before.

Nuclear winter will kill more then the nukes themselves. Nukes themselves will cause minimal casualties. It’s the rads and the nuclear winter that causes the real casualties

The first thing that will happen is the black rain or (Ash rain) that will go up into the atmosphere. Not only is it highly radioactive but it is the ashes of everything and everyone that was immediately vaporized in the blast radius only leaving their shadows burned into the super sun bleached surroundings.

The long term affects are purely based on location, habitat and amount of bombs in the area. A few bombs here and there wouldn't make much of a large impact on the environment. See Tangooska, Chernobyl and the Japanese miracle as references.

Well according to science, a nuclear winter would be imminent as a result of numerous nuclear detonations around the world. That would come first, and I’d imagine desertification would occur over time. I think if nuclear war did happen to us we’d be far more likely to go completely extinct rather than there being enough survivors to last us a further 200 years like in Fallout unless enough people actually took shelter in underground vaults.

Well it depends on location really. And who’s involved. If China, the U.S. and Russia, had a fallout now, the magnitude of those explosions... it’s insane. But, with the nukes, we also have better defense systems than in the fallout world. Obviously it won’t stop them all, but it may stop enough. As a Texan, the biggest hotspots for getting nukes to high Heaven, would be DFW, Houston, and Austin. Maybe Galveston and Amarillo. Amarillo is a nuke base though so it’s almost certain to take a hit, as well as give one. The main hits would be on the Coasts and up near the Great Lakes. Places in the Midwest would probably be fine other than a few strays. Europe, you guys would probably be decimated... sorry. You’re just so packed together lol. The few who do survive though, will have to try to rebuild in the radioactive hellhole that is left behind. Honestly those who die in the blast would be lucky.

^Yeah honestly I don't like Europe's chances and I live in England so double fucked. The naval dock at Portsmouth would almost certainly be a target so there goes Hampshire in that scenario.