You have a curious view about the onus of proof. The (necesary) elements of the hypothesis in question are:
1. CO2 and CH4 are greenhouse gasses,
2. greenhouse gasses are the main cause for the atmosphere to be warmer than grey body temperature.
3. increases concentration of greenhouse gasses increase the temperature of the atmosphere significantly, (global warming).
4. humans increase the concentration of greenhouse gasses.
hence humans cause global warming
There is little reason to challenge elements #1 and #4, but how about #2 and #3? If those were to be true then variations in greenhouse gasses in the past would necesarely lead to corresponding changes in global temperatures. So whether or not that evidence is there, should be decisive for the confirmation or falsification of those elements #2 and #3.
So how about that proof?
Albedo variation is only a link in the chain of causes and effects. Variation in cloud cover may have many causes, not necesarily warming.
Now, isn't that a coincidence? We're talking about the same source
! However, what Pallé et al (2006) failed to verify, is the correlation between their results and the global temperatures. They just erroneously assumed that the temperatures continued to rise, perhaps because that's what you hear all the time.
See also this thread