Falcon 9 burns trough around 500t of propellant while Electron trough around 12t. So, you need roughly 41 launches of Electron to match one of Falcon 9. 41 Elec

Falcon 9 burns trough around 500t of propellant while Electron trough around 12t. So, you need roughly 41 launches of Electron to match one of Falcon 9. 41 Electrons can deliver max 10t of payload costing around 246 millions $, while single Falcon 9 more than 20t in expendable version costing less than 100 millions $. But the issue with big rockets is that they can take a payload to pretty much a single orbit. You will never find 41 clients that want to go the same orbit. So, quite often big rockets are flying below their max capacity. Also, rockets contribution to humanity CO2 emission is close to zero. I would not be surprised if some launches of agricultural satellites had positive net impact on environment due to more efficient usage of water, fertilizers and pesticides that monitoring from space allows. If F9 fired 100 times a year and converted 100% propellant mass into CO2 (it actually produces a lot of water) it would be 0.0001% of world emissions.