Estimating, monitoring and minimizing the travel footprint associated with the development of the Athena X-ray Integral Field Unit

Abstract

Global warming imposes us to reflect on the way we carry research, embarking on the obligation to minimize the environmental impact of our research programs, with the reduction of our travel footprint being one of the easiest actions to implement, thanks to the advance of digital technology. The X-ray Integral Field Unit (X-IFU), the cryogenic spectrometer of the Athena space X-ray observatory of the European Space Agency will be developed by a large international consortium, currently involving 240 members, split over 13 countries, 11 in Europe, Japan and the United States. The travel footprint associated with the development of the X-IFU is to be minimized. For that purpose, a travel footprint calculator has been developed and released to the X-IFU consortium members. The calculator uses seven different emission factors and methods leading to estimates that differ by up to a factor of 5 for the same flying distance. These differences illustrate the lack of standards and regulations for computing the footprint of flight travels and are explained primarily, though partly, by different accounting of non-CO2 effects. When accounting for non-CO2 effects, the flight emission is estimated as a multiple of the direct CO2 emission from burning fuel, expressed in CO2-equivalent (CO2eq), with a multiplication factor ranging from 2 to 3. Considering or ignoring this multiplication factor is key when comparing alternative modes of transportation to flying. The calculator enables us to compute the travel footprint of a large set of travels and can help identify a meeting place that minimizes the overall travel footprint for a large set of possible city hosts, e.g. cities with large airports. The calculator also includes the option for a minimum distance above which flying is considered the most suitable transport

Reducing the Carbon Footprint of Academic Conferences: The Example of the American Society of Tropical Medicine and Hygiene

“…14 We conservatively assumed economy travel only; premium economy, business, and first-class seating are associated with ∼1.5-, ∼2-, and ∼3-fold higher emissions, respectively. 14 44.6 million kilometers flown. This distance equals 58 return trips to the moon (assuming an average distance of 384,400 km or 238,855 miles 16 ).…”

“…We then selected the flight option with fewest changes using an online travel planner 13 ; for some long-haul flights, this is likely to generate a conservative estimate of travel distance and carbon emissions because journeys with multiple connections are often cheaper. 14 For U.S. conference participants from Delaware, District of Columbia, Maryland, and Virginia, we conservatively assumed no air travel. We then calculated distances between the presumed airport of departure and Washington Dulles International Airport along a geodesic (great circle) path.…”

“…These emission factors take into account 1) direct emission of radiatively active substances (e.g., CO 2 ), 2) emission of chemical species that alter radiatively active substances, and 3) emission of substances that trigger generation of aerosol particles or change natural clouds. 14 We conservatively assumed economy travel only; premium economy, business, and first-class seating are associated with ∼1.5-, ∼2-, and ∼3-fold higher emissions, respectively. 14 The 4,834 conference participants originated from 110 countries across six continents ( Figure 1 ).…”

“… 14 We conservatively assumed economy travel only; premium economy, business, and first-class seating are associated with ∼1.5-, ∼2-, and ∼3-fold higher emissions, respectively. 14 The 4,834 conference participants originated from 110 countries across six continents ( Figure 1 ). Their combined return flights accounted for 27.7 million miles or 44.6 million kilometers flown.…”

The carbon footprint of large astronomy meetings

“…We computed the CO 2 -equivalent (CO 2 e) emissions associated with every plane or train trip using an online travel footprint calculator with its default settings, and we refer the reader to the accompanying paper 9 for a discussion on the pitfalls of the methods used in these calculations (for example, assumptions about the radiative forcing index). For car trips, we used Google Maps to compute the shortest road distance and assumed emissions of 110 g km -1 (ref.…”