In Civ5, what (global) negative combat modifiers do exist?

Question

I'm asking this because I know of the following two, but I'm not totally sure of the details at the moment (and whether there exist any other):

(It would be nice if answers could include quantitative measures as well.)

• If your people are VERY unhappy, combat strength of all units is decreased.
• Units that need a strategic resource get a penalty if you lose access to this resource. (How does this work exactly?)

Answer 1

If happiness falls below -10, you get a -33% combat modifier.

If you do not have enough strategic resources (less resources than units that require that resource), all units that need the resource get a -50% combat modifier.

I assume the combat modifiers from social policies apply also to you, if the AI civs have the appropriate social policies, but I never saw that in action. Most of these are also not strictly global, but depend partly on enemy/friendly territory or nearby units. The Total War social policy is global, if the AI researches it it should count against you.