What kind of evidence are you looking for? They have verified it in many ways, and with many observations. Satellites measure the albedo imbalance directly.
Climate change in earths history is a well described phenomenon. It is not possible however to verify significant human influence on climate change due to the lack of long term data.
Wrong. We can easily measure the proportion of what was contributed by humans, and which by nature. Natural causes like volcanoes are a drop un the bucket compared to our contribution.
And yet you assume that this in some way affects climate change, based on what information?
Based on observation of the albedo imbalance following the increase in greenhouse gases. It is directly observed and measured.
