What is the probability that significant global warming is occurring or will soon occur, and is primarily caused by human actions?

I remember being annoyed with this question, as I am annoyed with most "news" articles on "the debate", with gibberish such as "Climate denier". That's not even English.

"Significant" and "soon" are both a problem here.

I think your question overly complicates, as it's only one component of warming, "due to human activity". Just CO2? Greenhouse emissions? All the forests and herd animals ever killed? Transformation of species populations? Pollution?

How about what the average global temp will be in the 2050s, according to some existing instrumental measurement regime?