Academic conferences have long been celebrated as the beating heart of scientific exchange, but a new study suggests they may also be among the most carbon-intensive activities a researcher undertakes. A team at the Institute of Science and Technology Austria (ISTA), led by Lucky N. Kapoor and Paul Schanda, has produced one of the most detailed quantitative audits yet of the greenhouse gas emissions tied to conference attendance. By combing through the attendee lists of ten major magnetic resonance meetings held between 2016 and 2025, the researchers calculated that a single trip to a typical European conference emits more than one tonne of carbon dioxide equivalent per person — and that intercontinental journeys can reach five tonnes, roughly an entire year’s worth of a fair per-person carbon budget.
The study, published in the journal Magnetic Resonance, focused on the flagship meetings of the magnetic resonance community: EUROMAR, the Experimental Nuclear Magnetic Resonance Conference (ENC) and the International Conference on Magnetic Resonance in Biological Systems (ICMRBS). These events draw between roughly 470 and 1,100 participants and last four to six days. The team gathered participant lists from conference organizers, apps and abstract books, then used automated text extraction and manual curation to link each attendee’s institutional affiliation to a city of origin. From there, they computed the presumed travel trajectory of every participant and converted those distances into emissions.
The conversion was deliberately rigorous. For journeys shorter than 400 kilometres one way, the researchers assumed train travel, using actual rail distances calculated through the Carbontracer service rather than straight-line estimates. Longer trips were assumed to be flown. Crucially, the team refused to rely on the optimistic figures often quoted by railway companies. They added an infrastructure surcharge of about 25 grams of CO2 equivalent per passenger kilometre to account for the construction and maintenance of rail lines and the heating and cooling of stations — costs that most carbon calculators quietly ignore. Drawing on data from the Austrian Federal Railways and a study of the Austrian rail network, they estimated that indirect emissions roughly multiply the direct emissions of a train journey by a factor of about 2.5.
For aviation, the accounting was similarly unforgiving. The researchers applied a radiative forcing index, which captures the fact that greenhouse gases emitted at altitude warm the planet more powerfully than the same gases released at ground level, with values ranging from 1.3 to 3 depending on altitude. They also corrected the great-circle distance between cities by an uplift factor of 8 percent to reflect real-world flight paths, holding patterns and takeoff inefficiencies, and added an estimated 15 percent for airport infrastructure. Even so, they acknowledge their flight figures are likely underestimates by about 20 percent, because connecting flights — which can add up to 100 kilograms of CO2 per additional takeoff — were not modelled.
The headline numbers are striking. Total travel emissions for a typical EUROMAR conference came to 700 to 900 tonnes, or about 1.2 to 1.3 tonnes of CO2 per participant when flights are assumed beyond 400 kilometres, dropping to roughly one tonne if attendees take trains up to 800 kilometres. For conferences held outside Europe, per-person emissions were two to three times higher, with intercontinental round trips reaching four to five tonnes. The geography of attendance matters enormously: more than 80 percent of EUROMAR participants typically come from Europe, and the most frequent one-way journey is between 800 and 1,200 kilometres. At the 2024 ICMRBS meeting in Seoul, 200 of about 580 participants were from the Republic of Korea, yet the per-person average excluding those local attendees exceeded 3.1 tonnes.
Perhaps the most provocative finding is how conference travel stacks up against the rest of a scientist’s carbon ledger. The team compared it with the emissions of actually doing magnetic resonance research: building and running NMR spectrometers with their supercooled magnets, powering cryogenics, computing, laboratory consumables, buildings and commuting. For a model facility with three spectrometers at 600, 700 and 800 megahertz shared by 20 researchers, the annual operating footprint ranged from 0.8 to 5 tonnes per person, depending on how fossil-heavy the national electricity grid is. In other words, attending a five-day EUROMAR conference can emit more carbon than running NMR experiments for an entire year in a country like France, where the grid is largely low-carbon. Traveling from Europe to the ENC meeting in California, the authors note, emits more CO2 than half a year of making samples, performing NMR and computing combined.
Accommodation, catering and the venue itself, by contrast, barely register. A three-star European hotel generates roughly 10 to 20 kilograms of CO2 equivalent per person per night, meals add perhaps 14 to 28 kilograms over a five-day meeting, and the venue contributes around 10 kilograms per attendee. All told, everything except travel amounts to a few tens of kilograms — meaning transportation accounts for the overwhelming majority of a conference’s footprint. The comparison with the global carbon budget is stark: the IPCC’s SR15 report estimated a remaining budget of about 420 gigatonnes of CO2 equivalent for a two-thirds chance of limiting warming to 1.5 degrees Celsius, which distributes to roughly 4.5 tonnes per person per year in 2025 — a figure that must fall to zero by 2050. A single transatlantic conference trip can consume an entire annual allowance.
The study does not stop at diagnosis; it models remedies. Choosing more geographically central venues emerges as a powerful lever. The team used the EUROMAR 2024 attendee list to predict emissions if the meeting had been held in Frankfurt, Lyon or Vienna instead of more remote locations, and found that central sites could cut per-attendee emissions by more than a factor of two — a saving of roughly 500 to 800 tonnes for a conference the size of EUROMAR. A similar calculation for the ENC meeting suggested that moving it from California to the US East Coast would save about 25 percent, or 400 to 500 tonnes, thanks to shorter distances for European attendees and the density of NMR groups on the East Coast. The authors caution, however, that systematically favoring central locations disadvantages colleagues in more distant regions, a trade-off that must be weighed.
Decentralized conferences offer another path. The researchers modelled a two-site EUROMAR in which participants travel to whichever hub is closer to their home institution, with plenary talks shared by video link. Savings of around 25 percent appeared realistic — consistent with earlier case studies that projected one-third reductions for three-hub conferences and up to 80 percent savings for split meetings. Fully online formats are in a different league altogether: videoconferencing generates an estimated 0.15 to 0.25 kilograms of CO2 equivalent per participant-hour, or about 1.6 kilograms per person for an eight-hour day, two to three orders of magnitude below in-person meetings. A large astronomy conference that went online reduced its footprint by a factor of 3,000. Online formats also broaden access, lifting barriers for junior scientists, caregivers and researchers at underfunded institutions — attendance at the largest European geoscience meeting rose by more than 60 percent when it moved online during the pandemic.
At the individual level, the choice between train and plane matters enormously. Across model journeys from cities such as Frankfurt, Vienna and Paris to prospective EUROMAR venues in Oulu, Gothenburg and Lyon, train travel saved between 75 and 95 percent of emissions compared with flying — a fourfold to twentyfold reduction — even after the team’s deliberately conservative accounting of rail infrastructure. Even in worst-case scenarios with low radiative forcing assumptions and night trains with reduced capacity, trains still saved at least 40 percent. The authors also point to behavioral evidence that trimming travel need not cost careers: a survey of German scientists found respondents attended about three conferences per year on average, and while 8 percent of postdocs reported receiving a job offer through conference travel, a separate study of air travel and scholarly metrics found no significant relationship between the volume of flying and research output measured by indicators such as the h-index. The team hopes their open data and scripts will help conference organizers and individual scientists make informed, quantitatively grounded choices — and spark a community-wide conversation about how the scientific meeting, one of academia’s most cherished traditions, can survive the transition to a net-zero world.
Subject of Research: Carbon emissions from conference travel in the magnetic resonance research community and strategies to reduce them
Article Title: Quantifying the carbon footprint of conference travel: the case of NMR meetings
Article References: Kapoor, L. N., Ružičková, N., Živadinović, P., Leitner, V., Sisak, M. A., Mweka, C., Dobbelaere, J., Katsaros, G., & Schanda, P. (2025). Quantifying the carbon footprint of conference travel: the case of NMR meetings. Magnetic Resonance, 6(2), 243-256. https://doi.org/10.5194/mr-6-243-2025
Image Credits: AI Generated
Keywords: carbon footprint, conference travel, magnetic resonance, NMR, greenhouse gas emissions, EUROMAR, train versus plane, academic mobility, climate mitigation, sustainable science, virtual conferences, aviation emissions
News Source: Sloane Callahan. (October 10, 2026). One Flight, One Tonne: Scientists Audit the Carbon Cost of Conference Travel. Scienmag.
