How Do We Know That We Are Causing Global Warming?

The vast majority of people will not become climate scientists, science is hard and even people that do it for a living don't understand absolutely everything, and thus we're faced with the problem of not being able to all understand everything about climate science. Why then should the average person trust that global warming is occurring and leading to changes in our climate? I've compiled my favorite lines of evidence for it here.

How Much Spread Do We See In The Models?

All of these analyses use a combination of models that I've referred to as ensembles. Specific analyses vary in which models they use based on what data are available and what data make sense to combine. What sort of spread exists in the temperature models?