I went straight from Mozilla Navigator to Firefox 1.0.
Tabs were such a crazy new thing back then. You would show tabbed browsing to someone (rather than opening new windows) and they thought you were a wizard. IE5 didn’t have tabs, so nerds moved to Mozilla/Firefox. Then IE6 came out but still didn’t have tabs. By the time IE7 came out, I’d had tabbed browsing for 5+ years.
The reduced operating emissions take 10+ years to outweigh the enormous construction emissions of nuclear. (Compared to gas.)