THE RESILIENT SPECIES

Today’s post will be the last one in my series about climate change and human evolution, and that’s why I would like to share with you some of the thoughts I developed over the past months.

The reason why we study the past so meticulously is not only to satisfy our insatiable curiosity – we also want to be able to learn from the history in order to understand or predict the future. So, what have we learned from this blog that can be applied for the future, especially under a changing climate?

On one hand, I showed that our species was ‘born’ from climate change: our two main characteristics, bipedalism and a large, complex brain were adaptations to environmental variability. Thanks to these features we have become extremely adaptable and we were able to migrate, settle in all kinds of environments and endure numerous climatic fluctuations. On the other hand, I showed that such flexibility has not always guaranteed survival – all but one of the Homo lineage vanished, and a climatic factor is likely to have played a role in some of those extinction events.

However, I haven’t mentioned a very important fact about the relationship between people and climate. Thanks to our intelligence and creativity we became the only species able to alter the environment – including climate – to such an extent. In all my previous posts I just wrote about the effects of climatic changes on our species, but I haven’t explored how our species influences the climate.

The human impact on the Earth’s climate is an unprecedented phenomenon and, let’s face it, we’re just starting to understand it. That is why it is incredibly hard to predict what is going to happen to us in the future. All the lessons from the past might become invalid when confronted with the unparalleled rate of climate change and erratic human behaviour. However, there is no doubt that never before have we had as much power to shape the environment we live in. So, are we going to make the Earth uninhabitable and doom ourselves to extinction, or are we going to use our knowledge, adaptability and imagination to continue being the dominant, most resilient species?

HOMO SAPIENS - THE ONLY SURVIVOR

In my previous posts, I briefly mentioned the once incredible diversity of the human family tree and I looked at the possible reasons behind the disappearance of the Neanderthals. But what about all the other hominin species that did not make it, although at some time in the past they were thriving? Searching for answers is extremely hard. Entire populations who lived for thousands of years left behind only a few incomplete fossils on which we base our speculations.

As an example let’s take Homo florensiensis – also nicknamed ‘the hobbit’.  Homo florensiensis lived on the island of Flores in Indonesia, measured a little bit more than a metre in height and a brain of a size of an orange (Brown: 2012). There are numerous theories on the emergence of the species, but I want to focus on its disappearance which took place approximately 12,000 years ago. There are numerous theories on the emergence of the species, but I want to focus on its abrupt disappearance which took place very recently - approximately 12,000 years ago. One of the popular theories states that H. florensiensis (as well as Stegodon, the pygmy elephant which constituted the main source of food for the hobbit) went extinct because of a volcanic eruption at ca. 12,000 years ago. Some scientists say it could have been the arrival of Homo sapiens that put an end to the millennia of H. florensiensis presence on the island. However, there is some evidence suggesting that changes in climate could have played their part too. The stalagmite records from Indonesia show a sharp increase in rainfall, following a long arid period and coinciding with the H. florensiensis extinction (Westaway et al.: 2007). Unfortunately, due to the lack of complete evidence it is still impossible to tell for sure which of the possible causes had a major part in the vanishing of the hobbit.

With the demise of H. florensiensis, the diversity of Homo lineage finished. We are not entirely certain why H. habilis, H. erectus and other species of the genus Homo disappeared. Environmental stress? Competition?  Interbreeding? Climate change? Or combination of all the factors? Due to that uncertainty, in my next post I would like to focus not on the reasons for extinction of the other species, but on the factors making Homo sapiens the only survivor of the Homo family. I will also look at what the story of our success can mean for our future under the rapidly changing climate.