1) Anthropogenic CO2 emission rates in 1990 were greater than natural sinks could offset.
2) Under any reasonable set of assumptions, rooftop solar PV has significantly lower emissions per kWh than the cleanest fossil sources. In 2014 the IPCC estimated a median value of 41 gCO2-e/kWh for rooftop PV generation vs. 490 for combined cycle natural gas generation.
3) Perhaps some of the CO2 avoidance will be squandered eventually as solar becomes cheaper, thereby encouraging use of more electricity, but so far total electricity use is uncorrelated or even anti-correlated with the presence of rooftop solar generation. "Rooftop solar" and "energy-thrifty building construction/operation" cluster together, so far, rather than displacing each other.
Perhaps, although i'm quite skeptical about a difference in distribution and installation. And even in the case of manufacturing, one must only consider the delta between them rather than full cost of manufacturing solar.
2) Under any reasonable set of assumptions, rooftop solar PV has significantly lower emissions per kWh than the cleanest fossil sources. In 2014 the IPCC estimated a median value of 41 gCO2-e/kWh for rooftop PV generation vs. 490 for combined cycle natural gas generation.
3) Perhaps some of the CO2 avoidance will be squandered eventually as solar becomes cheaper, thereby encouraging use of more electricity, but so far total electricity use is uncorrelated or even anti-correlated with the presence of rooftop solar generation. "Rooftop solar" and "energy-thrifty building construction/operation" cluster together, so far, rather than displacing each other.