Critical look at graphics illustrations.

Graphs are powerful images, and unlike written assertions (“opinions”), there is often little discussion about graphs. But they also claim things, and, I notice it myself, I am more inclined to accept something from graphs than from words. Probably because it is easier to recognize your own opinion in them; with words it is easier to question things immediately. But the last few weeks some ‘graphs’ popped up in the internet media , which I want to question: I forced myself to take a critical look….

First, this one: a graph by Arup, about CO2 storage. [1] Recently much shared on all kinds of forums on the internet. Coincidentally, I had just gotten my own thoughts regarding CO2 storage in wood via buildings lined up and published, so that graph immediately triggered.

What do we see: The gray part is CO2 storage. It starts, say, 50 years ago, and is immediately allocated to the maximum during construction (of a bridge in this case, but similar for a building), and later decreases somewhat due to maintenance, among other things. And there is apparently an end of life bridge/building ( why?: there are even Roman bridges and aqueducts still in function…), where we have to do something with that wood.

The first question is: which moment in that timeline should we take as the established CO2 benefit of that structure: at the beginning, somewhere halfway, or the end? The end, I hear someone say, is in 50 years or so. Indeed, but then why start counting the CO2 storage from 50 years ago? But that is exactly the crux: Whoever evaluates a building, has as a system boundary that building, and at t=0 there is therefore 0-CO2 (zero) stored (also for that bridge). It was already stored in the 50 years before, the act of building does not change that. In fact, the graph is the other way around: the biggest contribution is only 50 years later when at least the felled trees have grown back, see my earlier articles. [2][3] And then again, what about end of life? I wrote about that too earlier, in 50 years time there will be panic, and CO2 emissions regarded as a crime, let alone that we demolish something ourselves [4]. So the graph is misleading with respect to CO2, and suggestive of what will happen in the future. How it actually could be I have somewhat provisionally drawn next to it. ( the blue line)



A second graph came along to illustrate all the positive effects recycling can have.[5] But of course you can only recycle when something has been discarded: and that is only a benefit , materials spending wise, if the discarded product has not been replaced by a new one …. Of course, it could be that the new product is made 1 to 1 from the remains of the former product, but that implies two things: that there is a delay in having that product as a function or service, and that the amount of materials in circulation is stable. The accompanying graph [from 5] suggests that we keep growing in material use, but that this can be compensated by more and more recycling. That is nonsense of course: more and more recycling is only possible if there is more and more new material in circulation, and then only a part of it.material-district And its already predicted that our material use will grow strongly , up to a factor of 4 by 2060 (OECD)[6]. Its impossible to fulfill that with recycled material….

A recent comprehensive Finnish study [7] says this: The vast majority of the proposed Circular Economy support systems have yet to be manufactured. As it is not possible to recycle something that has yet to be manufactured, the source for this unprecedented quantity of metals will have to be sourced from mining.*


The graph suggests that by 2050 you can recycle 2x as much as what is currently in use, for 2x as much material use?

Finally, The CO2 Graphs that are all around. We make beautiful pictures of CO2 reduction graphs, even the IPCC, and then we are reassured because one day they will end up at 0, those lines. But most of the time they remain just beautiful plans and are therefore mainly wishful thinking. But even that is not correct, and by definition a misrepresentation.

What you should show, the only honest way, is the actual and absolute situation: the annual emissions compared to the remaining emission budget, (by the way also introduced by IPCC after studies by scientists), but seldom put into graphs. Not even by governments or others, for that matter.

And then you get the following comparison: The left shows the reductionist reasoning: we are talking about reducing Dutch CO2 emissions.


And suppose we manage to achieve net reductions every year over the total**, then you get the left-hand graph: taken 5 tons of reduction here every year, to end up at 0 somewhere in 34 years. That seems ok, everyone happy. (if it would happen at all, and much too late anyway).

But that says nothing about what is really happening: If we take the absolute CO2 emissions, then they are capped at a 66% chance of staying below 1.5 or two degrees. Divided by population gives a maximum for the Netherlands of 756 Mton at 1.5 degrees,

And the only way to make visible the effect of what we are doing, is to take the absolute emissions cumulatively. And then you get the graph on the right… At the bottom in red are the same reduction figures as on the left, only the scale has changed. The blue ones are actually cumulative emitted. And then you can see that there’s not a reassuring drop, but a cumulative explosion… You can see that with absolute cumulative data we’re passing the limit within 5 years. This is the graph that actually needs to be published and updated every year and should guide actions and decisions.

Conclusion: Charts are very illustrative, but again: be careful with them and look at them critically.


Next time: the circular economy illustration revised.


*also from Finnish report [4]:

“Global reserves are not large enough to supply enough metals to build the renewable non-fossil fuels industrial system or satisfy long term demand in the current system. Mineral deposit discovery has been declining for many metals. The grade of processed ore for many of the industrial metals has been decreasing over time, resulting in declining mineral processing yield. This has the implication of the increase in mining energy consumption per unit of metal.”

** Often it is not even about the total, but about the reduction of one product. This says nothing about the total effective reduction. If 1 product has a lower energy consumption, but we buy more of it, then the net result is zero or even negative. What happened with energy saving light bulbs at the time, we were going to introduce more light points.



[2] CO2 1:

[3] CO2 2:

[4] on end of life of a building:

[5] source , though could not find the specific report

[6] OECD Global Material Resources Outlook to 2060, febr 2019 ,

[7] The Mining of Minerals and the Limits to Growth , Geological Survey of Finland, march 2021


Author: ronald rovers