Geology question

Question

What fraction of Earth’s evolution has been influenced by humans?

Answer 1

Great question Airah.

Unfortunately, there is no “absolute” straightforward answer.

However, we can narrow the field of possible answers a bit by determining two values:

1.      What model of Human Evolution do we wish to subscribe to.

2.      What the definition of “influenced” might be.

I am of the inclination that if humans were present, then humans “influenced” what was going on with earth, in some aspect.

First, we need to figure out which version of human evolution we wish to follow. 

Do we follow the Judao-Christian model of creation where the Earth is just slightly older than 6,000 years, and humans were created on day six of the creation epoch; In which case, Humans influenced Earth for about 100% of the time that Earth has been around.

or

Do we follow current scientific theory which suggests that the Earth is some 4.5 billion years old, and modern humans evolved about 200,000 years ago? But human ancestors show up in the fossil record between 6 million and 2 million years ago. 

or

Do we want to know how long humans have influenced the Earth in major ways by their activities? In that case, it is believed civilizations began as early as 6,000 years ago, which would have necessitated greater influence on the Earth with larger-scale agriculture, water diversion, building cities, etc.

While significant human influence on the Earth likely started with the beginning of “civilization,” the real major influences started in earnest in the 1800s’

So, if you want a fraction, set it up where the age of the Earth is the “denominator” and the presence (influence) of humanity is the numerator, reduce the fraction, and Volia’.

All you have to do is decide “What model of Human Evolution do we wish to subscribe to”, and “What the definition of “influenced” might be” and go from there.

If you are working on this problem for a course that you are taking, I recommend following your text and lecture materials and asking your Teacher/Professor for guidance. 

Hope this helps.

Sincerely

Ron P