Recommendations Emerging from Carbon Emissions Estimations of the Society for Neuroscience Annual Meeting

Abstract

The annual Society for Neuroscience (SfN) meeting yields significant, measurable impacts that conflict with the environmental commitment of the Society and the Intergovernmental Panel on Climate Change (IPCC) recommendations to address the climate emergency (IPCC, 2018). We used 12,761 presenters' origins, two online carbon calculators, and benchmark values to estimate 2018 meeting-related travel, event venue operations, and hotel accommodation emissions. Presenters' conference travel resulted in between 17,298 and 8690 tons of atmospheric carbon dioxide (t CO₂), with or without radiative forcing index factors. Over 92% of authors traveled by air and were responsible for >99% of total travel-related emissions. Extrapolations based on 28,691 registrants yielded between 69,592.60 metric tons of carbon dioxide equivalents (t CO₂e) and 38,010.85 t CO₂ from travel. Comparatively, authors' and registrants' hotel accommodation emissions equaled 429 and 965 t CO₂e, whereas operation of the San Diego Convention Center equaled ∼107 t CO₂e. We relate SfN meeting-related emissions to potential September Arctic Sea ice loss, labor productivity loss in lower-income equatorial countries, and future temperature-related deaths. We estimate emissions reductions of between 23% and 78% by incentivizing between 10% and 50% of the most distant registrants to attend virtually or connecting between two and seven in-person hubs virtually. Completely virtual meetings may yield a reduction of >99% relative to centralized in-person meetings and increase participation of women, queer and transgender scientists, and scientists from low- and middle-income countries. We strongly recommend adopting alternative meeting modes such as four or more in-person global hubs connected virtually by 2030 and fully virtual by 2050.

Keywords: climate change; global warming; hybrid conference; multiple-site conference; virtual conference.

Figure 1.

Neuroscience 2018 presenting authors’ global origins.

Figure 2.

Costs of attending current, centralized annual Neuroscience meetings in USDs. Error bars represent registration costs from $100 to $400 that are associated with membership status.

Figure 3.

Travel-related emissions estimations, presented in metric tons of atmospheric carbon dioxide equivalents (t CO₂e), derived from great-circle distances between Neuroscience 2018 presenting authors’ (N = 12,761) latitudes and longitudes and current, centralized meeting locations using emissions rates from Jungbluth and Meili (2019). Also included are extrapolations for 28,691 registrants derived from mean emissions rates and percentages of Neuroscience 2018 presenting authors by travel mode. Radiative forcing index (RFI) factors account for an increased effect of global warming because of CO₂ and non-CO₂ emissions in the upper troposphere and lower stratosphere. The 45% emissions reduction targets are relative to the mean travel-related emissions estimation across the three business-as-usual in-person meeting locations, San Diego, Washington, DC, and Chicago. Including emissions from connecting flights could increase emissions more than shown. Extended Data Figure 3-1 presents the travel-related emissions presented here by travel mode.

Figure 4.

Travel-related emissions estimations, presented in t CO₂, of multihub suites relative to the mean emissions estimation from San Diego, Washington, DC, and Chicago meeting locations. All values are computed using great-circle distances between Neuroscience 2018 presenting authors’ origins and meeting locations and emission rates from Jungbluth and Meili (2019). Radiative forcing index (RFI) factors account for an increased effect of global warming because of CO₂ and non-CO₂ emissions in the upper troposphere and lower stratosphere. One multihub suite contains the three reference hubs of Frankfurt (FRA), Los Angeles (LAX), and Tokyo (HND). Thereafter, we added, in order, Chicago (ORD), Dallas/Ft. Worth (DFW), Mexico City, and Jakarta. The second suite contained ORD, Istanbul (IST), and Sydney (SYD), to which we added Philadelphia, Riyadh, São Paulo, and HND. We did not account for connecting flights, which could increase emissions more than shown. Extended Data Figures 4-1 and 4-2 present counterfactual multihub meeting travel-related emissions by travel mode, hub scenario, and location that we derived from Neuroscience 2018 presenting authors (N = 12,761) for the suite of hubs that include FRA, LAX, and HND.

Figure 5.

Neuroscience 2018 presenting author (N = 12,761) distribution by travel mode, hub scenario, and location for counterfactual multihub meetings. Reference hubs are spaced 7–9 h apart in coordinated universal time. Four additional hubs are spaced 1 or 2 h apart from a reference hub. FRA, LAX, and HND coordinated universal times are +2, −7, and +9, respectively. LAX serves as the reference hub for ORD, DFW, and Mexico City International Airport (MEX). CGK is the reference hub for HND. Extended Data Figure 5-1 presents Neuroscience 2018 presenting authors (n = 957) who originated from a developing country by World Bank income category in Fiscal Year 2019, hub scenario, and location.

Figure 6.

Travel-related emissions, presented in t CO₂, for business-as-usual (BAU) and hybridized Neuroscience meetings when 10%, 25%, and 50% of the most distant attendees participate virtually. All values derived from emission rates per kilometer in Jungbluth and Meili (2019) and relative to BAU in-person meetings. The emissions reduction target accounts for radiative forcing index (RFI) factors and is relative to the mean travel-related emissions across BAU sites. We did not account for connecting flights, which could increase emissions more than shown.

Figure 7.

Summary of travel-related emissions for Neuroscience meetings by meeting mode. All estimations are derived from emissions rates in Jungbluth and Meili (2019). Radiative forcing index (RFI) factors account for an increased effect of global warming because of CO₂ and non-CO₂ emissions in the upper troposphere and lower stratosphere. Values for one venue, 10%, 25%, and 50% virtual are means across San Diego, Washington, DC, and Chicago meeting sites. Emission reduction targets are 55% of mean emissions for the three business-as-usual, in-person meeting sites. Three reference hubs include Frankfurt, Los Angeles, and Tokyo. Thereafter, we added, in order, Chicago, Dallas/Fort Worth, Mexico City, and Jakarta. Including emissions from connecting flights could increase emissions more than shown.