Evidence?

I've been trying to find the evidence for the widely-accepted theory of anthropogenic global warming. This is the part of the climate change debate that is supposed to be really settled. Even skeptics admit that humans are having an effect, they only argue about the scale of that effect.

As far as I can tell the evidence amounts to co-incidence--that is, two things happening at the same time. Here is the argument in a nutshell:

1. The greenhouse effect is real.
   
2. Greenhouse gasses cause the greenhouse effect.
   
3. Carbon Dioxide is a greenhouse gas.
   
4. Humans produce carbon dioxide.
   
5. Ergo, humans, by releasing CO2, are causing the warming.

I'd point out that coincidence does not mean causality.

The more that comes out about the science of global warming, the more convinced I am that climate science is at its heart non-rigorous, lazy, and sloppy. Or, that climate science relates to hard science about the way that brie relates to parmesan.