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 money that could have been spent otherwise 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 interactions between scholars that can increase the value of the research itself : the concentration of relevant science as well as interesting conversations 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 empirical 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 estimate . 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 expected to be worth at least that ?
Box 1 : Estimating the costs and benefits of a scientific conference
C = C t + C m
+ C CO2 = t conference
t project
= V · + V · + C CO2
B = r · i · V
If we assume that the benefits B of a conference 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
t project m conference
m project
m conference
m project
B - C = V · ( r · i - - ) - C CO2
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 considerations like this one to make actual decisions about whether a given activity 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 factors , we should probably not spend too much time on it or rely on the results blindly .
We cannot immediately stop emitting excess CO 2
, and we are unable to determine good cost-benefit estimates 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 similar to my own .
I use Magnetoencephalography ( MEG ) to measure magnetic fields in the human brain . To function , the MEG has to be continuously cooled using liquid Helium , and 14.5 liters of liquid Helium evaporate in a single day . It is not easy to find information on the carbon footprint of helium production , but helium is mostly obtained as a byproduct from natural gas purification and might therefore have a similar footprint . 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 emissions to about 16 tons of CO 2 equivalent . In 2015 , groups at the MEG center 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 .
Finally , I will make the assumption of traveling to one international conference per published paper , by airplane , using the distance Stuttgart-Chicago as an example . This leads to another 3 tons of CO 2 per paper .
Only a few neuroscientists use MEG . But most of us depend on big , expensive machines , laboratory animal facilities or extensive computing power , all of which have considerable environmental footprints . Most of us like to travel and take opportunities to give talks , attend conferences or courses whenever we can . Therefore , most of us probably emit greenhouse gasses in a similar order of magnitude , even if the individual contributors vary .
So what can be done ? For those of us who are near the bottom of the scientific hierarchy , there is only so much we can do ; the most significant factor everyone can influence is probably travel . While there might be a not-toodistant future in which physical travel is not necessary anymore due to virtual conferences [ 7 ], this will not be achieved by personal decisions of single scientists – but if you are not entirely sure whether it is worth going to an international conference , you can let the climate be the decisive factor and give it a miss – or try out a more local meeting that can be reached by train , bus or car .
May 2017 | NEUROMAG | 11