Our fossil brains struggle with the concept of exponential growth. Often, we do not get beyond straight-line (linear) projections, or we expect that ‘everything will stay the same’. Regardless of whether we are looking at economic growth, the increase in infection rates or global warming, we do not see that these are increasing exponentially. Because our frontal lobes still believe that the world will develop in the same way as it did in the Stone Age (that is: not very quickly), time and again we respond to developments too late. We are too short-sighted to get our heads around exponential growth. And that causes a lot of damage.

A good example to make clear how difficult exponential growth is for us to understand, is the well-known story about the inventor of the chessboard. The inventor presented the very first board as a gift to the emperor. The emperor was very pleased and asked the inventor what he would like in return. “Rice”, said the inventor, “a grain of rice on the first field and then double the previous amount on each of the 64 fields”. The emperor was a linear thinker and did not realise that if he was to meet this exponential request he would have to cough up a total of 9.2 billion grains of rice for the last field of the board - equivalent to around 2,000 times the current annual global production. There are two versions of this story. In the first version the panicking emperor has the inventor beheaded, while in the second version he appoints the inventor as his economic advisor.

The exponential reality

Understanding the concept of exponential growth may therefore be helpful. For instance, people who study technological developments see the exponential increase in computing capacity as the gateway to the Valhalla of plenty. Economic advisors with a tech bias talk about ‘the second half of the chessboard’ and are incredibly optimistic about the future. But not all exponential growth is positive, and we do not even realise that. Take the coronavirus. For too long, we continue to believe that it will not be so bad, until the speed at which the virus spreads takes us by surprise, and we are hit by a second wave.

Our economy is also growing at an exponential rate, without us realising it. The Dutch economy's average annual growth rate of 3% since the 1950s means that economic activity doubles once every 23 years. If growth had only been 1%, then it would have taken from 1950 until now for the economy to double in size. About exponential economic growth we could actually say that it has also resulted in exponential material prosperity and is therefore a positive thing. However, this exponential growth has also led to an exponential increase in the burden on our environment: through material and soil use, the reduction of biodiversity and pollution. And here lies the crux of what we keep failing to understand: our ecosystem does not grow exponentially.

And then there is also the issue that often the changes that we have set in motion by overburdening the ecosystem are not linear (and sometimes exponential). Often, we do not even know exactly how and where these changes feed through. What we do know is that there are certain tipping points beyond which developments can no longer be reversed.

Anyone who points this out now often gets the first treatment that the emperor supposedly doled out: virtual beheading. The fossil brains of many people still lack the capacity to question exponential economic growth. The tech gurus are much more appealing.

A lesson in statistics before it is too late

And so we keep underestimating the speed or the extent of change. What can we do about this? Research by the US National Academy of Sciences shows that in order to create support for the social restrictions that are needed to combat the corona pandemic it helps to educate the public about statistics. We could do the same thing with regard to the environmental restrictions on economic growth.

However, the same research also shows that people do need to see the necessity of such restrictions if they are to change their behaviour. And that is still often the problem, because when people actually display the desired behaviour, the problem no longer develops exponentially, and they can claim in hindsight that there was actually no exponential growth at all. And so we continue to live with our linear perception.