There is overwhelming evidence to support the increasing concerns regarding the health of our planet. Wildlife habitat and biodiversity is reducing, air quality is deteriorating, disease patterns are changing, oceans are warming and acidifying; all of which have significant health effects for mankind.^{Reference Trompiz1–4} Although widely debated, one could argue that the most pressing threat for humanity is climate change, resulting from the release of “greenhouse gases” by farming, deforestation, and the burning of fossil fuels to support industry and travel. Consequently, global average sea levels are expected to rise up to 82 cm by 2100.^{Reference Hemming, Iowe, Biginton, Betts and Ryall5} Climate change is already displacing small indigenous communities around the world,⁶ with many countries with low level populations considering their approach.⁷ Climate change is harming human health, and needs a broad range of strategies to reduce this harm.^{Reference Charlesworth, Gray, Pencheon and Stern8,9}

There is a growing relationship between environmental harm and planetary health, defined as the “health of human civilisation and the state of the natural systems on which it depends”.^{Reference Whitmee, Haines and Beyrer10} In causing planetary harm, in this report we examine the hypothesis that widespread travel to conferences is harming human health.

Academics attend conferences to keep abreast of relevant research trends, to network, to be educated, and to present their own research. Traditionally the only way of accomplishing these goals was to travel locally, or as flights became cheaper and more available, internationally. With increased access to international conferences, year on year conference attendance has been growing,¹¹ with the global conference market having an important economic, and environmental, impact. Internationally the economic spend on industry meetings, conference and events is significant. Annually, the UK, Canada, Denmark, and Australia spend a respective $21.24 billion, $19.8 billion,¹² $2.75 billion,¹³ and $17.6 billion¹⁴ on these types of events. Conferences generate money for the host city, in terms of hotel accommodations, use of conference facilities and expenditure for local businesses. According to eventbrite, in the UK, on average 258 people attend each conference a year with 10,000 venues, and over 1.3 million business events held every year. Larger conferences attract many more people.¹⁵ In 2018, the congress of the European Society of Cardiology had 32,858 participants and the congress of the European Society of Medical Oncology had 27,700 participants.

As conferences have increased, so has the environmental impact. A major concern with the amount of conferences is the effect that the required air travel has on planetary health. One source states that the air travel contributes 5% of the carbon equivalent emissions.^{Reference Sullivan16} The interesting fact about planes is their environmental impact does not just relate to their carbon emissions. Planes also create contrails, with the soot from a plane allowing water vapor to condense and form cirrus clouds lasting for some hours. These clouds trap ice which in turn trap heat, and in turn warm the climate.^{Reference Lee, Fahey and Forster17,18} Whereas the carbon dioxide emissions from aviation is predicted to be 84 mW/m² by 2050, the warming effect from the effects of contrails will be almost twice as high, at 160 mW/m².^{Reference LePage19} It is suspected that face-to-face conferences also causes other environmental impacts.

It could be argued that traditional paediatric cardiology conferences with in-person meetings can now be replaced by web based e-learning platforms, forums, and meetings. In the last few years, e-learning has become part of the mainstream in medical education.²⁰ With the COVID-19 pandemic, e-learning has become the new normal, with many primary, secondary and tertiary institutions turning to online platforms such as Zoom, Teams, and a variety of educational software to educate, and interact with their students. The academic conference industry has been slow to follow similar trends prior to the Covid pandemic. Some conferences started to allow online attendance prior to the current COVID-19 pandemic (e.g., the AMEE conference).²⁰ However since the Covid pandemic there has been a dramatic transition to a virtual framework. Several organisations have been producing excellent webinars in paediatric and congenital cardiology including “Heart University”, “Congenital Heart Academy” and the “World University for Pediatric and Congenital Heart Surgery”.

On Wednesday, 6 May, 2020, one of the first webinars in congenital heart disease was hosted by the Heart University, a free online educational platform, hosted by Cincinnati Children’s Hospital, for providers of both congenital and paediatric acquired heart disease.^{Reference Tretter, Windram and Faulkner21} The webinar series is entitled Contemporary Questions in Congenital Heart Disease Webinar Series. The first webinar in this series was entitled “Tetralogy of Fallot: How can we avoid poor outcomes late after repair?”, and represented the largest gathering at that time of congenital heart disease providers, outside the Quadrennial World Congress of Pediatric Cardiology and Cardiac Surgery, with 1374 participants from 100 countries across 6 different continents.

For the purposes of this study, we calculated what the environmental impact would be if all 1374 attendees at the paediatric cardiology Webinar attended the conference in-person in Cincinnati (typically lasting 2.5 days for the biannual conference). The city of residence for the attendee was used to calculate their travel distances as part of a Life Cycle Analysis calculation. Unlike other papers in this area we were also keen to present the results both as impact factors but also as normative results; showing the impact compared to a person equivalent impact (the impact on the environment a person would have in a usual life year).^{Reference Zotova, Pétrin-Desrosiers, Gopfert and Van Hove23,Reference Klöwer, Hopkins, Allen and Higham24}

Materials and methods

Ethical approval for the Webinar study was obtained from the University of Alberta (JW) from which data was extracted regarding attendee participation and city of origin.

Definitions for all terms are provided in the Appendix 1.

Disability adjusted life year: The disability-adjusted life year is a measure of overall disease burden, expressed as the number of years lost due to ill-health, disability, or early death.

Comparative life cycle assessment: A specific life cycle assessment where two or more products are compared using life cycle assessment methodology.

Life cycle assessment: Life cycle assessment (LCA) is a methodology that strives for the assessment of environmental burdens along an entire (product) value chain.

Life cycle inventory: Life cycle inventory (LCI) involves making an inventory of input and output flows for a product system. Such flows could include inputs of raw materials, and output releases of products to air, land, and water.

A comparative life cycle assessment of a traditional (face-to-face) and a virtual medical conference was undertaken at Trinity College Dublin, Ireland in conjunction with Eastman Dental Hospital, London.

The software OpenLCA v1.10.2 was used for the Life Cycle Assessment, alongside the reference database Ecoinvent v3.7. The Life Cycle Assessment methodology was applied in line with ISO standards and across the 16 environmental impact categories recommended by the Product Environmental Footprint Category 2 Rules Guidance guidelines.²²

The functional unit was defined as 1374 delegates attending a 2.5 day congenital heart disease conference. Assumptions and exclusions are described in Table 1.

Table 1. List of assumptions made in this life cycle analysis

The system boundaries are shown in Figure 1. The entire product system, including geographical location, was compared, in order to account for travel to Cincinnati from worldwide for the traditional conference. A life cycle inventory was created for each type of conference based on these assumptions.

Figure 1. System boundaries.

Data from the life cycle inventory was modelled in OpenLCA v1.10 for the Life Cycle Impact Assessment (LCIA). The Life Cycle Impact Assessment method for each impact category was selected based on the PEF Category Rules Guidance and is described in Table 1.

Disability Adjusted Life Years (DALYs) were also calculated for the following human health impact categories: water consumption, ionising radiation, global warming, ozone formation and depletion, particulate matter formation, human carcinogenic and non-carcinogenic toxicity.

The life cycle inventory is shown in Table 2.

Table 2. Ecoinvent processes, and unit quantities used in the life cycle assessment

Results

The life cycle impact assessment results are shown in Figure 2. The virtual conference performed better than the traditional conference in all 16 environmental sustainability impact categories.

Figure 2. Life cycle impact assessment results.

Figure 2 also illustrates which parts of the life cycle inventory contributed to the overall impact. For the traditional conference, air transport (long haul passenger flights) was the biggest contributing factor across 15 out of 16 impact categories (ranging from 37%–98%). Water scarity was the only impact category where building operations was the biggest contributor (64%). For the virtual conference, it was the residential energy use that was the biggest contributing factor, responsible for 91% of the climate change impact.

Figure 3 illustrates the normative results for a conference. The climate change impact for a 2.5 day, face-to-face conference for these 1374 people was equivalent to 245 times what an average person would use in 1 year, and the fossil fuel resource use 400 times.

Figure 3. Life cycle assessment normative results.

For a virtual conference the results are much smaller; the climate change impact for the same conference for 1374 people would use less than 3 times what an average person would use in one year.

There are a number of reasons that the impact categories for the face-to-face conference are so high. The majority of the climate change burden of the face-to-face conference was due to the fossil carbon dioxide air emission from air travel. Similarly the resource use, energy carrier’s burden of the conference was mainly due to ground crude oil use for petroleum and gas production, used in air travel. The non-cancer human health burdens of the face-to-face conference were mainly due to the lead and zinc emissions to air from passenger air travel. The terrestrial eutrophication burdens of the face-to-face conference were mainly due to the nitrogen oxides emissions to air from passenger air travel. In contrast the climate change burden of the virtual conference was mainly due to methane and carbon dioxide air emissions from hard coal plants for electricity production for attendees to use residential energy, remaining at home rather than travelling.

The traditional face-to-face conference resulted in a loss of 2.7 DALYs, and the virtual conference just 0.5 DALYs. Water scarcity was the biggest contributing factor to both DALY results (48% and 91% of the total DALYs respectively) followed by fine particulate matter formation (45% and 7% respectively).