I can't tell if you are being serious, but just to be clear: I do not think that climate change is "scary because of nukes". Climate change is scary in its own right. Global famine is going to be very unpleasant whether or not it sparks WW3. But we do have nukes, and nukes + climate change could bring about the end of civilization in my lifetime with probability much greater than zero. And, what is scariest of all, most people's behavior indicates that this possibility is not even on their radar screens. Most people are still behaving as if the really serious shit is several generations away. It's not. The wolf is at the door, as you say, much closer to 10 years than 100.
Global warming is scary because of nukes.
The timeline till we get widespread crop problems is 15-20 years.