Ignored? Kind of because it suits the carbon tax crowd. Unexplained? No.

Nothing about it is unexplained, it happens evey 11 years, it was predicted in 09 that it was going to happen, but even taking that into account the sun has been far more void of sunspots than is normal. The standard solar minimum and expected lower temps would have still gone for a couple more years anyway but the quiet sun is more complicated.