The CO₂lumnist: Carbon scopes participating at the Tokyo 2021 Olympics

The CO₂lumnist: Carbon scopes participating at the Tokyo 2021 Olympics

22-07-2021 | Columna

Investors rely on data to make decisions on climate strategy. But the data is far from perfect, and it doesn’t always add up. In the first of a new series of columns taking a more light-hearted look at the issue, and as the Olympics begins in Tokyo, Robeco data scientist Thijs Markwat draws parallels with trying to figure out the heptathlon.

  • Thijs Markwat

This summer, for the first time in history, the modern Olympic games takes place in an odd year. I am not a big fan of athletics, and I have never ever watched athletics outside of the Olympic games. But for some reason, during every Olympic edition, I always tend to watch parts of the athletic heptathlon.

I find it very impressive for one single person to be proficient in so many different disciplines. The different events that make up the heptathlons are show in the table below. Interestingly, the heptathlon differs quite a bit between men and women.

Inversión sobre el clima: de la emergencia a las soluciones
Inversión sobre el clima: de la emergencia a las soluciones
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Women (outdoor)

Men (indoor)

Long jump

Long jump

High jump

High jump

Shot put

Shot put

Javelin throw

Pole vault

100 meters hurdles

60 meters hurdles

200 meters dash

60 meters dash

800 meters dash

1000 meters dash

The main difference between the men’s and women’s heptathlon is the location – the women’s is outdoors while the men’s is indoors. This also explains a bit the different events between men and women, as javelin throwing in an indoor venue might not be the smartest idea. The indoor location also limits the sprint distances to 60 meters. At the end of the Olympic heptathlon, after all heptathletes have completed the seven events, one athlete receives the gold medal.

But how to decide who the winner is? Clearly, scores of different events cannot simply be summed into a total score. For example, adding a 2-meter high jump to a 22-second 200 meters dash score… would that make sense? Of course it doesn’t. Therefore, a special scoring system was developed by the mathematician Karl Ulbrich to make different events comparable and addable.

For the remainder of this memo I am going to simplify matters and only look at the long jump, the high jump and the shot put, which are the common events in both heptathlons. Let’s now look at the women’s heptathlon records for these three events, as shown in the table below.



High jump



Long jump



Shot put






These results are all expressed in meters and thus, at least technically, can be added up. But still, we could argue about the meaning of the 26.6 meters. Does adding the outcomes of the high jump, long jump and shot put makes any sense? To get some more insights in the interpretation of this total score, I have added the column ‘spread’.

This number indicates the common range of outcomes. So, high jumps usually vary between 1.7 and 2.0 meters, while shot puts generally vary between 14.2 and 17.3 meters. There is a clear positive relationship between the distance and spread of the events. Thus, events covering a larger distance have more impact on the total score. Therefore, if scores are blindly added in this ‘triathlon’, a top ranking in the shot put seems to be a prerequisite for victory, while the high jump is just in there for show.

It doesn’t always add up

Does the fact that you can add things up imply that you should add things up? No of course not, but this is exactly what happens with carbon accounting! Scope 1, 2, and 3 emissions can technically be added as all are denoted in tons of CO2.

In terms of size and spread it is actually pretty accurate to state that scope 1 emissions are like the long jump, scope 2 emissions like the high jump, and scope 3 emissions like the shot put. Scope 3 emissions are much larger and also have a much larger spread. Therefore, like the shot put in the example, the only thing that really impacts aggregated carbon emissions are scope 3 emissions. And like the high jump, scope 2 (and to a lesser extent scope 1) is just in there for show.

Thus, instead of blindly adding scopes, a method should be developed to make the scopes comparable like they do for heptathlons! Obviously, for carbon accounting, this method should ideally resolve the severe double counting issues in scope 3. However, this will be very difficult to achieve, and therefore an alternative scoring system could be a great (intermediate) solution. But remember, blindly adding all scopes is like only including scope 3.

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