Neuromag May 2017 - Page 11

every activity. If the benefits are higher than the costs, we should do it – it’s worth it. But what are the costs and benefits of, say, traveling to a scientific conference? On the cost side, the most obvious points are the time and mon- ey that could have been spent other- wise as well as the carbon emissions for travel, accommodation and the conference venue. Benefits include an effect on the outreach of the research presented – if the science has some value and more people are confronted with it, the value will be multiplied – as well as positive influences due to in- teractions between scholars that can increase the value of the research it- self: the concentration of relevant sci- ence as well as interesting conversa- tions can help generate good ideas. It might be relatively straightforward to write down an equation capturing all these factors. However, bringing the equation to life can prove extremely difficult. How much more impact does a result make when it is presented at a conference compared to when it’s not? This is not an easy question, but it should be possible to find an empiri- cal answer. What difference does the input of the academic community at a conference make? This one is already quite a lot harder to answer, but it may still be possible to get a good esti- mate. However, what is the value of a scientific project? Should we use data from the past to assess what average impact each study ever conducted has made? Should we just use the funds a project received as an approximation, because if society is willing to spend a certain amount on it, it must be ex- pected to be worth at least that? Box 1: Estimating the costs and benefits of a scientific conference C = C t + C m + C CO2 = m conference t = V· conference t project +V· m project + C CO2 B = r · i · V If we assume that the benefits B of a confer- ence are determined by a reach effect r, an interaction effect i and the value of the scientific project V, and the costs C are determined by the time investment t conference , the monetary investment m conference and the climate costs C CO2 , the benefits of a conference can be estimated as: t conference m conference B - C = V · (r · i - t - m ) - C CO2 project project If B-C > 0, the conference provides an additional value. But what are the values of all the individual variables? This makes it very difficult to use con- siderations like this one to make actual decisions about whether a given activ- ity is overall beneficial or not. While it might be helpful to try to estimate costs and benefits in this way to get a general feeling for the important fac- tors, we should probably not spend too much time on it or rely on the re- sults blindly. We cannot immediately stop emit- ting excess CO 2 , and we are unable to determine good cost-benefit esti- mates for most of our decisions. Are we doomed? Do we have to hope for miracles or is there anything else we can do? I believe there is a third way that will ultimately effectively tackle climate impacts while not being too demanding on anyone along the way. All it requires is that more researches gain awareness about the climate costs of their work and are willing to act on this awareness – even if it is only in very little steps, as long as these steps are bigger than the ones that everyone else is taking. The first step in becoming aware is to gain an idea of science’s climate impact. Is it even significant? And are any of the emissions avoidable? In a recent case study, the carbon impact of a 4-year PhD in Environmental Sciences was estimated at 21.5 tons of CO 2 , which was equivalent to 2.7 tons per paper or 5.4 tons per year, 75% of which was due to travel [4]. As values might be very different for different scientific fields, I tried to crudely estimate the carbon impact of research more simi- lar to my own. I use Magnetoencephalography (MEG) to measure magnetic fields in the hu- man brain. To function, the MEG has to be continuously cooled using liquid Helium, and 14.5 liters of liquid He- lium evaporate in a single day. It is not easy to find information on the carbon footprint of helium production, but he- lium is mostly obtained as a byprod- uct from natural gas purification and might therefore have a similar foot- print. Under this assumption the 657 kg of Helium required every year lead to the gigantic emission of 241 tons of carbon equivalent [5]. Luckily, the MEG Center installed a recovery system which enables the recycling of about 95 percent of the helium used which – taking into account the energy needed for liquefaction – reduces yearly emis- sions to about 16 tons of CO 2 equiva- lent. In 2015, groups at the MEG cent- er published 10 papers, leading to an amount of 1.6 tons of CO 2 per paper due to the use of MEG. To process the high-dimensional data the MEG gives us, we need a lot of computing power. For this purpose, my group has a high-performance cluster, whose energy consumption I estimate at 7700 kWh per year – leading to emissions of about 3 tons of CO 2 , or 0.6 tons of CO 2 per paper published in 2015. 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