conference_footprint

compute the CO2 footprint of an academic conference
git clone https://a3nm.net/git/conference_footprint/
Log | Files | Refs

README.md (4407B)

      1 This file explains how the carbon footprint of Highlights'26 was computed.
      2 
      3 ## Data collection
      4 
      5 We collected information about the travel plans of participants via the
      6 registration form, containing the following fields:
      7 
      8 - Arriving from…
      9 - Arriving by…
     10 - Leaving to...
     11 - Leaving by…
     12 
     13 Unfortunately, this year, the form was only completed with these fields after
     14 participants had registered. So participants were asked during the conference to complete the extra fields, but not everyone did so. The missing fields were extrapolated as explained below.
     15 
     16 There are 155 participants, of which 37 are local and 118 are nonlocal.
     17 
     18 For those participants that did not provide complete travel information (36 of
     19 them), I assumed that they were travelling to and from the institution to which
     20 they were affiliated. Further, based on Highlights'25 data, I assumed that trips
     21 of <=600km were done by train, and trips of >600km were done by plane. I checked
     22 that the computation was not too sensitive to this choice.
     23 
     24 We prepared a file with the following tab-separated fields:
     25 - field 0 is the origin
     26 - field 1 is the transportation mode
     27 - field 2 is the destination
     28 - field 3 is the transportation mode
     29 
     30 (These files are not versioned because they can be considered private
     31 information.)
     32 
     33 We run: 
     34 
     35   ./generate_trips.py 48.198964 16.369916 0.2
     36 
     37 Where the arguments are the latitude and longitude of the conference venue, and
     38 0.2 is the noise to add. This generates a file trips_anonymized.csv containing,
     39 for each trip leg, the mode ("plane", "train", "bus/coach"), the distance (in
     40 km, rounded, with noise), and the information about extended stays. A file
     41 trips.csv is also produced for debugging (with the data without noise and with
     42 personal information). A file map.geojson is also produced with the map of
     43 participants and transportation modes and private information (to be used as an
     44 image only).
     45 
     46 The file trips_anonymized.csv can then be fed to co2.py which computes the
     47 carbon footprint (see below). This gives (from the anonymized data):
     48 
     49 total CO2e emissions (tons): 33.435452                 
     50 for mode train: CO2e emissions (tons): 2.391939
     51 for mode plane: CO2e emissions (tons): 30.958393
     52 for mode bus/coach: CO2e emissions (tons): 0.085120
     53 for distances <2000 km, plane is used for 107/222 trips
     54 for distances >=2000 km, plane is used for 14/14 trips
     55 flights of over 2000 km account for 7.821959 CO2e emissions (tons) i.e. 23.394207 percent of total for 14/236 total legs
     56 distance by plane: 152714
     57 num by mode train: 108
     58 num by mode plane: 121
     59 num by mode bus/coach: 7
     60 dist by mode train: 64647
     61 dist by mode plane: 152714
     62 dist by mode bus/coach: 3040
     63 
     64 Hence, the total CO2 footprint is 33 tons CO2e (it is the same with the
     65 non-anonymized file). Around 93% of emissions are due to plane travel.
     66 
     67 The average footprint per onsite non-local participant (118) is around 
     68 283 kgCO2e. The average footprint per onsite participant (155) is around 
     69 216 kgCO2e. (These figures are computed from the anonymized data.)
     70 
     71 ### Carbon footprint (unchanged from 2024)
     72 
     73 Like in 2022, we compute the CO2 fotprint following the
     74 [labos1point5](https://labos1point5.org/ges-1point5) data, which is adapted from
     75 the French agency [Ademe](https://www.ademe.fr/). We use the values from 2022
     76 without updating them to ensure that the methodology is comparable.
     77 
     78 - For train, we count **37 gCO2e/pkm** (international train). This is pessimistic in France, very
     79   pessimistic for TGV, but similar to the 41 gCO2e/pm for national (UK) rail
     80   given by [Our World in
     81   Data](https://ourworldindata.org/travel-carbon-footprint).
     82 - Plane is counted following
     83     [labos1point5](https://labos1point5.org/ges-1point5), including the effect
     84     of contrails:
     85   - 258 gCO2e/pkm for less than 1000km
     86   - 187 gCO2e/pkm between 1001km and 3500km
     87   - 152 gCO2e/pkm above 3500km. This value is consistent to the 150 gCO2e/pkm
     88       value for long-haul flight given by [Our World in
     89       Data](https://ourworldindata.org/travel-carbon-footprint) (also including
     90       contrails)
     91 - For bus/coach, we count 28 gCO2e/pkm as the coach value given by [Our World in
     92     Data](https://ourworldindata.org/travel-carbon-footprint) as there is no
     93     value in labos1point5.
     94 
     95 ## Trends relative to 2025
     96 
     97 The footprint is slightly more than the one estimated in 2025 (29 tCO2e), but in
     98 the low range of the footprints since 2022 (27-42 tCO2e).
     99