A studypublished in Nature Geoscience has double-checked, and confirmed, that climate change is mostly human-induced. "An alternative line of evidence" that it uses proves that most observed climate change (74 percent of it) comes from greenhouse-gas emissions, not natural variability.
We basically knew that already, but it's always good to have independent confirmation.
Moreover, the study states unequivocally that a pet climate skeptic theory is downright wrong. The paper's abstract puts it this way:
"Even if natural climate variability were three times greater than that estimated by state-of-the-art models, it is extremely unlikely to have produced a warming trend as pronounced as that observed in the real world."
Or, to put it into numbers, the study calculated a net warming value of around 0.5 °C since the 1950s and changes in solar radiation contributes at most, a 0.07 degree C [0.126 degree F] to the warming.
In other words, natural shifts are playing a role in the changing climate. But they're downplayed by the changes which humans are responsible for and must take actions.
To the source:
Three-quarters of climate change is man-made, Nature