Flora et Fauna: Climate & Weather systems influence.

If one sits down and looks at the world, it becomes immediately apparent that the weather changes what can live in a given region. A location that has a lot of water can not support lifeforms that require a more arid environment. It would be easy to just ignore this thing and say 'oh, they just have what they need where they are.'  It can create a jarring disconnect from the reality you've built when you have a Saharan camel living on the Arctic tundra with out any modifications to the situation.

Now, it is fantasy or some other variant of fiction that you are writing and this gives you a significant amount of leeway as to how much you can bend the rules of what is 'real' and how far you can depart from what is commonly understood to be normal. I, however, find that realistic fiction elements will need to take in to consideration the very environment of the setting in the sense of what sort of weather and such there is.

Weather systems are a big driving factor in real world events. Storms of historic size and ferocity are more than proverbial plot devices. They can effect permanent changes to the landscape, the sociopolitical situation, and the most basic elements of the necessities for life. Just look at the difference of Louisiana before and after Hurricane Katrina. The differences are staggering (and, honestly, rather horrifying). It may be nice to say that the lovers take a romantic walk in the rain, but if you are at a place where rain is a frequent happening, this will change how the rain is viewed by even the characters themselves. Rain everyday for a two weeks means that you may have problems with flooding. And there is a good chance that the characters don't see that drizzly weather as something romantic but rather as another damned inconvenience.

Climates are interesting because when they shift they can make massive changes to an entire region. As a result, stresses between different groups become larger in some cases and smaller in others. Looking at Medieval Europe during the period of the Little Ice Age, we find that the great famine happened during this era. We find that there was a stark increase in problems that resulted in things like the loss of the Norse settlements in Greenland during the 15th century because they were unable to sustain enough crops of livestock to remain present.

It is no small coincidence that this period was one that saw a great deal more of conflict in communities and on the international scale. This, after all, was the period of the Hundred Year's War, the Black Death, and the Inquisition. When sufficient stresses pile up on a community, they become fractured and tend to ... well, eat themselves. Climate change can cause an enormous amount of stress to drive the conflicts within your works. The questions as to why a place is suffering bad droughts may be because of something shifting the weather patterns. The problems with droughts would lead to famine, problems in the economy, and loads of social problems. Conversely, a place suddenly blessed with good growing conditions and abundant resources would develop an entirely different set of challenges. Perhaps a case of the people who live in the areas of more depleted resources coming to acquire the resources of the others by way of sword and axe?