# Carbon emission calculator

If you want to make your own virtual conference, you can first calculate how much carbon emission will be produced and compare to the emissions from an oversea return flight.

Who can access the recording?

## A few information about the calculation

Here is how we quantified how much emission will be produced for a given conference, be it a 10 people workshop for a day or a 1000 people conference for a week. For video streaming during the conference, we assume that 40 g of CO2 are emitted per hour per person (international average) (see source on CarbonBrief). Another way to get this number is to take the average electricity consumption per Gb of transmitted data, which is ~0.04 kWh/Gb (which is the average of the range given by the IEA or see Aslan et al. 2017 for a similar value). Then, we can convert it to (Burtscher et al. 2020) the quantity of CO2 emitted using that it is 0.24 kg/kWh (see ref). For 4Mbps (similar to the Netflix average), it leads to 17 gCO2e. Accounting for the electricity consumption of devices, this number goes up by roughly a factor 2 (Burtscher et al. 2020), which is similar to the previous value. We then reduce this value by a factor 2 to account for the difference between the mean bitrate used by Netflix (4 Mbps) and that of our tool (~2 Mbps for the default medium resolution). We then multiply by the time the conference lasts and the number of participants and can work out the final carbon dioxide mass emitted by the virtual conference.

For conference video storage, we calculate their emission over 3 years based on the number of averaged views we estimated but that will be refined when we have more statistics from our website. After 3 years, the organisers or their company will be contacted to check whether the videos should be put offline (as some more recent conferences on the same field or by the same participants may have already happened) to save on carbon emissions.

Sources we used to quantify how much carbon is emitted for a given conference: Shehabi et al. 2014, Schien et al. 2014, Andrae et al. 2015, Aslan et al. 2017, Park et al. 2017, CarbonBrief, IEA.