The Great Deceleration and proposed alternative interpretation of the Anthropocene

Abstract

Is the Anthropocene a new geological epoch and can its beginning be determined? The so-called Great Acceleration data, used repeatedly in support of the concept of the Anthropocene as a new geological epoch, are closely examined. They are supposed to be characterised by a clear intensification of growth (sharp increase, acceleration) in the mid-20th century. They revealed the opposite effect: they are characterised by decelerations either at precisely the same time when accelerations were expected or over the entire range of data, the phenomenon described here as the Great Deceleration. Implications of this study are two-folds: (1) contrary to expectations, these data cannot be used to determine the beginning of the Anthropocene and (2) the common deceleration questions whether humans alone can cause a transition to a new geological epoch. Investigation of the growth of the genus Homo in the past 2,000,000 years suggests that what is now called the Anthropocene could be just a natural continuation of the gradual evolution of human activities and impacts over a long time, without a sudden intensification and without a convincing evidence for a transition to a new geological epoch.

Anthropogenic data question the concept of the Anthropocene as a new geological epoch

“…It is well-known that growth of human population is now slowing down (see for instance US Census Bureau, 2021). With the slowing down growth of human population it is only natural to expect that human activities and impacts might be also slowing down, and indeed they are (Nielsen, 2021). This well-known deceleration of the growth of human population and the absence of sustained intensification around 1950 CE or around any other recent time question the concept of the Anthropocene as a new geological epoch.…”

“…If the assumed extraordinary acceleration was supposed to demonstrate how the Earth System departed from its Holocene status, then the absence of this acceleration might suggest that there was no departure, no transition to a new geological epoch, described as the Anthropocene. Consequently, these data, the data for the other two key anthropogenic indicators (human consumption of energy and growth of human population), and the so-called Great Acceleration Data (Broadgate et al, 2014; see also Supplementary material), which demonstrated systematic decelerations (Nielsen, 2021), question the concept of the Anthropocene as a new geological epoch. They suggest that there was no human-induced geological transition.…”

“…The prominent feature of the logistic growth is that it approaches asymptotically a certain maximum value (it levels off). Mathematical description of this type of growth is presented in the Supplementary material of the earlier publication (Nielsen, 2021). Its unique and characteristic feature, which distinguishes it from all other S-shaped types of growth, is that its growth rate decreases linearly with the size of the growing entity (in this case, with the reservoir capacity).…”

“…It is, therefore, obvious that whatever is increasing was smaller before a certain, arbitrarily selected time, and larger after that time. Growth trajectories describing anthropogenic indicators were not only increasing but, in general, they were also increasing progressively faster, before they decelerated in the second half of the 20th century (Nielsen, 2021). For such trajectories, it is easy to find many examples of not only small and large values before and after an arbitrarily selected year, but also of slow and fast increase.…”

“…The second issue is significantly simpler because data describing human activities and impacts can be easily analysed. Recent analysis (Nielsen, 2021) of a large body of such data (Broadgate et al, 2014) demonstrated systematic decelerations around 1950 CE, i.e., around the time when systematic accelerations were expected.…”