Environmental Effects

Sometimes the physics of the world go weird, those ways things have always worked change. Everyone who's lived through a System Initialization knows this to be true. But it doesn't end there. Mana flows through the world, and can have different resonances that when concentrated in an area can have interesting effects on the world. Aether and other extradimensional energies can also do this.

Environmental Effects are areas of these strange energies affecting the world in weird ways.
Magic can be easier for one specific kind, perhaps an area is less dense in aether for some reason and your skills and regens begin to suffer from not enough energy causing pain and damage to you. Not only that, maybe gravity fluctuates or shifts in an area, maybe insects or reptiles or something has a spike in reproductivity, perhaps plant life blights or mutates with strange or unfortunate effects.
Land can be blessed, sanctified, consecrated, desecrated, cursed, hexed, as well as nullified magic in the area or rampant random magics. Maybe physics itself starts warping the space or flow of time in the area. Maybe the dead can't cross over and remain bound to their bodies in death, stirring restlessly as their corpse rots. Even skills and traits can have their normal functionality altered or suppressed inside the area of an environmental effect.

Leylines always emit some type of environmental effect, as do portals, some aether infused natural elements (often radioactive pre-system), and even spell and enchantment effects though those are often just labeled as Auras incorrectly. Auras, whether natural Auras such as from powerful magic items or enchanted from the effects of a Skill or Spell are a vessel for local environmental effects. Auras however often have a coherent theme or affinity and are more often than not stable as opposed to non-aura related environmental effects.