The biggest source of emissions for many conferences, especially in developed nations and in the USA is long distance air travel. A single transcontinental flight's emissions/capita by itself is almost equal to the allowance of emissions/capita required to keep the planet under 1.5 degree Celsius by 2100 (above which we will face significant climate change impacts). There are also other major sources of emissions for conferences like hotel overnight stays, the associated use of energy and local mobility. This is aside from other major issues like cost disparities of traveling from developing to developed nations, which often excludes many from the former from participating.
The advantages of a virtual conference over an in-person conference include them being more accessible for people like parents, the disabled and the financially limited, cost savings for everyone involved, the aforementioned environmental benefits and also the major disadvantages of virtual conferences of networking and face to face contact, can now be replicated virtually.
This online conference on average saves 8690 CO2e emissions for every panelist who has to travel from India to attend the conference. Since virtual conferences still have a small, yet significant footprint, we will also be offsetting any emissions from the conference preparation phase to the actual virtual conference, for all the attendees, organizers and panelists.