Anthropogenic Transformation of the Terrestrial Biosphere: An Introduction

In today’s post I want to introduce the topic of anthropogenic transformation of the terrestrial biosphere. Over the next few posts I’m going to refer to Ellis (2011) and others in order to assess whether human populations have altered the terrestrial biosphere sufficiently enough to indicate that the Earth system has entered into a new geological epoch. I consider this to be an extremely important topic, well worthy of discussion as a change from natural, terrestrial biomes to ‘anthromes’ will bring about novel changes to many ecological patterns and processes and these will all have direct implications for Earth’s biodiversity.

See a decrease in seminatural and wild environments and an increase in dense settlements and villages since 1700. Source: Wired 

Human alteration of the terrestrial biosphere is not unprecedented and has in fact been significant for more than 8000 years. However, only in the past century has the majority of the biosphere been transformed into intensively used anthromes with predominantly novel anthropogenic ecological processes. There is strong evidence to show that humans have altered the Earth system sufficiently to indicate the emergence of a new geological epoch, one that scientists are calling the ‘Anthropocene’.

 

Human transformation of the terrestrial biosphere will leave a geological record that is significantly different from that of the Holocene or any prior epoch. Source: Plant Under Pressure

Some authors, including Jones et al. (1994), argue that any species with a large enough population will transform the ecosystems, simply by consuming the resources needed to sustain itself. However, scientists believe that there are profound differences in the way humans have been transforming the ecosystems, and some suggest that it is perhaps these differences that are responsible for the success of human society. Firstly, we are ecosystem engineers – just like beavers we are able to alter our environment. Secondly we are capable of using tools, and this makes the processes involved in ecosystem engineering all the more intense. Finally we are social creatures capable of collective action. Again this acts to increase our capacity to engineer the ecosystems (Ambrose, 2001).

Human development can be organised into three main stages:

1. The Palaeolithic human system – early humans were organised into tribes. Stone tools were first used around 2.5 million years ago and fire around 0.7-1.5 million years ago (Ellis, 2011) to improve hunting and gathering livelihoods.
2. The Neolithic human system – beginning around 0.01 million years ago. We see the first domestication of plants and animals here and humans began to use even more powerful tools for ecosystem engineering.
3. The Industrial human system – this is when we begin to use fossil fuels for energy. Industrial human systems are globally connected and the pace of social change is typically quite fast!

Illustration by Theodor de Bry (1591), showing indigenous Americans in Virginia cultivating maize fields. Some believe that the Anthropocene began with the rise of agriculture around 0.01Ma. Source: Recording the Anthropocene

So to develop this discussion further, in my next post  I'll explore the idea that these human systems are a force of biospheric change. In the mean time why not read the Ellis paper for yourself. It's a long one but I recommend it! It gives a good overview of many of the concepts of Global Environmental Change, including the Anthropocene and I found it particularly helpful in putting some of these complex concepts in context!