Geological time: It’s a big deal

Geological time is massive. The timescales involved are not easy to comprehend for our human minds, much like the size of the universe. Consequently the vast majority of humanity cannot quite grasp the size of the timescale that our planet operates on, and this is becoming ever-more problematic considering growing global issues such as climate change.

In 2013 global life expectancy was 71 years according to the World Health Organisation. The Earth meanwhile has now been around for over 4.5 billion years. Such a major difference between humanity’s concept of time, and geological time is resulting in a dangerous underestimation of the consequences of human activity on the Earth. Commonly when this issue is raised a whole range of statistics are quoted showing alarming species extinction rates, rising global temperatures, rising sea level figures, and so on. Statistics are a fantastic tool in science and a great source of evidence, but for many statistics are alienating, boring and hollow. They confuse an issue to the point where the take-home message is lost. Regarding the issue of humanities impact on the Earth, it may be of use to consider the reasons for concern via human examples, not numerical ones.

First, consider the history of the Earth in a human life. This does require some numbers, however the point it makes could not be clearer.

Imagine the Earth was 45 years old, not 4.5 billion. On this timescale the dinosaurs died out 8 months ago; the first humans evolved just yesterday; agriculture only began within the last hour and the industrial revolution happened just one minute ago.

The significance of this minute proportion of time is amplified when considering how humanity currently populates and utilises the Earth. We shape its landscapes, consume its natural resources and have now populated its surface in unprecedented numbers. Never before in its long history has our planet experienced such a successful and dominant product of nature as humanity. Our consumption and utilisation of the Earth is no great problem on a human timescale, but compared relatively to geological time the impact we will have is profound. The problem lies with the rate of humanity, not the actual activity. We have developed so much, so quickly – on a very human timescale. Our development, so successful it may be, has occurred at a rate completely unprecedented in Earth history.

Again there are many numerical and graphical means to explain this by, the classic example being the current rate of greenhouse gas emissions compared relatively to geological time, but it is sometimes better to consider the issue more simply. There are over 7 billion people on the planet today. Think of how many cars, houses, clothes and food that involves. Consider the number of power stations, roads and other infrastructure that requires. To then argue that humans do not and will not have some sort of major impact upon Earth’s future environments and climate defies common sense, but only if the relative scales of humanity and planet Earth are understood.

Another major problem is that in our day-to-day lives there is not much, if any, visual evidence of the impact one might expect human activity to be having. Why believe the cries of danger if it is not evident in our day-to-day lives? This is a major problem, and one that requires individuals to consider change from a point of reference alien to them – geological time. Observing change in our lives is something that many of us do on a day-to-day basis. Consider the reference point of a day in a human life. If the average human life spans 71 years, that equates to just under 26,000 days on Earth. The planet Earth equivalent of a day in its lifespan is nearly 175,000 years. This huge difference in relative scale demonstrates why it is so easy to underestimate the consequences of certain human activity upon the planet we call home.

When considering the impact that humanity could have on the future climate and environments of Earth it may seem that the industrial revolution, or simply using a car is by default wrong. This is not the case, and often an area in which the strategies for combatting the above issues fall short. We live in a human world that works in certain ways. Over the short time we have been around we have learnt the hard way what works for humanity and what does not. It is unconstructive, and frankly naive to suggest that civilisation should cease to exist in its current form and start over. That is not going to be popular or work in any sort of world. I am a big believer in technology and human innovation providing us with many of the solutions we need to combat the issues facing us here. However these innovations and technologies mean nothing if people do not understand the severity of the issues at hand and demonstrate the willingness and mindfulness to change.

Geological time is massive and it is very hard to grasp. However the importance of understanding it, and the differences in the timescales we observe change as humans, compared to that of our planet, has never been greater. Often I view the timescale of the consequences of human activity on the Earth similar to that of the lag time between going to the gym to exercise, and feeling physically fitter. After just one workout there is little evidence to suggest that the exercise has had any impact on your body, however over weeks and months of training, physical and visual improvements will become more evident and profound. Humanity’s impact on the Earth is much the same. In our day-to-day lives there is little evidence of our impact upon the Earth, but in the Earth’s day-to-day life (175,00 years remember!), the impact will be much more severe.


Share Darrow

We believe in the free flow of information. We use an Commons Attribution-NonCommercial 4.0 International License, so you can republish our articles for free, online and in print.

Creative Commons Licence


You are free to republish this article both online and in print. We ask that you follow some simple guidelines.

Please do not edit the piece, ensure that you attribute the author, their institute, and mention that the article was originally published on Darrow.

By copying the HTML below, you will be adhering to all our guidelines.

Chris Holdsworth 8 Articles
My writing interests spawn from my studies in Earth Sciences. The natural world fascinates and amazes me, but engaging and involving others in science is my greatest passion because of the ever-growing need for interest and understanding of the natural world.

Be the first to comment

What do you think?