It says that the dirtiest solar panels have a carbon footprint of ~70g/kWh.
Even in Germany or the US with their extremely high electricity consumption this amounts to 1 tonne of CO2 per capita annually - that's around the target footprint for sustainability.
For comparison coal has a footprint of ~880g/kWh and natural gas ~450g/kWh.
In short, solar panels are currently environmentally friendly.
Every other kind of environmental damage(as long as it's containable) can be prevented or undone with enough energy, so as long as that's being done all we need to worry about is the energy ROI.
Solar panels, throughout their life cycle, produce much more energy than it is required to produce and recycle them in an environmentally friendly way.