Insubstantial analogies

I have delayed posting because I wanted to put together something substantial, or at least coherently substantive, about our perceptions of the future and the past. Or at least a bit of visuals and sound that satisfied my aesthetics.
This post is neither.


A small personal digression…
Semi-retirement a little over a year ago gave me a 2 day week and time to devote to the blog. Unfortunately over the summer I have had to cover for work colleagues with holidays and illness. This has resulted in a 4-day week which I find very unconducive to the development of coherent and substantive articles or animation/graphic work!

The recent …pause,   –  hiatus ?  –  in posts does not represent a loss of interest or subject matter, I have accumulated a large amount of half formed chunks of work over the last couple of months, just not had the time to shape them into something postable.

So this post is something of a brief and probably half-formed reflection on the problem of making analogies that can help people understand unfamiliar subjects by giving them a more familiar example of the same processes.

There are many dynamic systems in the natural world that work in ways that are not well described by a simple, one-shot unidirectional linear chain of cause and effect. Over the years various metaphors have become commonplace. Fire for processes that need two components and a trigger, and are then self-sustaining.
Synergistic interaction can sometimes be explained by comparison with a ten-speed bike. 7 cogwheels interact to give more than the sum of the parts.
Ant nests as an example of emergent order from simple rules followed by a large number of equal components.

Recently the old issue has re-emerged of how much of the additional human carbon will be absorbed, and how fast, with different levels of emission,  with the imminent climate conference in Paris  re-energising the arguments about emission controls and limits.
Given new impetus by the growing zeitgeist of concern as extreme weather events, and more sharply, the migration and social disruption that is increasingly recognised to have a climate change component in its contributory factors, impact the developed world.

Because there is a high turnover of carbon between the air and the oceans and land biota there are some that claim that reducing emissions would rapidly reduce the airborne fraction of he fossil CO2 humans have added because it would be absorbed by the ocean/land sinks. The causal logic goes something like;-
If the carbon cycle can absorb 50% of our emissions this year of 6Gt so that only 3Gt remain in the atmosphere then if we stop emissions then next year the sinks will absorb 3Gt and the atmospheric CO2 levels will fall back to ‘normal’.

Its an error from lack of insight into how a dynamic system maintains an apparent stability.
The most common analogy raised to try and explain why this idea that the amount the sinks can apparently absorb in a year is not a measure of how much they will absorb if the inputs change seems to involve basins and bathtubs. Inflows, outflows and overflows. I do ‘get’ it, and it can be a good analogy, water flows can often be a useful model of complex dynamic systems. How a river both shapes and has its course shaped, by the surrounding landscape is always a fruitful model of mutual feedbacks.

But I was prompted to try and develop a different metaphor, analogy or model of the carbon cycle, and came up with this.-

The carbon cycle is like a Library.

The books on the shelves and on loan to the readers represent the carbon locked into biological systems and the CO2 in the atmosphere respectively.

There are always about the same proportion of books out on loan to the proportion in the library on the shelves, but which books are in, (sequestered) and which out on loan, (in the atmosphere) are changing every few weeks.

If more books are added to the library collection, perhaps by readers donating old books they have dug up, then even if it is just 5% of the total number of books borrowed and returned in a year it will increase the number out on loan as well as on the shelves.

Any persistent increase in the number of books the library has will persistently increase the number out on loan (as well as on the shelves). Only the slow process of discarding books when they get too damaged will reduce the amount in circulation. (the slow geological CO2 sequestration). So if the library gets fewer, or stops receiving, extra books it will still take a long time to reduce the number in circulation, and therefore the proportion out on loan (in the atmosphere).

Just because it makes sense to me does not mean it is helpful to anyone else. There are also objections that could be made to the assumption of a constrained ratio of books on loan / books on shelves as artificial and not necessarily true or proven in either context.

Any comments, improvements or alternatives welcome.


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