Having a child adds approximately 58.6 tonnes CO2e per year.
The maximum average CO2e per person per year to reach the Paris climate agreement goal of a 1.5 °C, is about 3-10 tonnes. We could do this with a 0.01 fertility rate for a few decades, until we're not catastrophically overpopulated anymore.
If you think your grandparents would prefer the Windows 8 or macOS type UI, then GNOME is the way.
I think Xfce or MATE is vastly better tho.