The Anthropocene

The Anthropocene
New geological ages are characterized by changes in global environmental conditions and large scale shifts in types of species. Recently Earth has entered into a new geological age: The Anthropocene, from anthropo = man and cene = new [geological age]. Humans are now changing the world on a global scale and ushering in the new era in geologic time.

In the past hundred years, we have seen:

1. The complete conversion of 15% of all ice-free land surface to human use.
2. The partial conversion of 55% of all ice-free land surface to human use.
3. The fixation (conversion of atmospheric nitrogen into fertilizer) of 190 megatons of nitrogen per year (in 2005), compared with pre-agriculture terrestrial fixation of 150-190 megatons of nitrogen per year by natural processes (Smil, 2000: 248) In addition, burning of fossil fuels and industrial processes released 100 megatons of nitrogen oxides and ammonia into the atmosphere in 1995 (Galloway (2008).
4. The appropriation of 25% to 40% of total net primary productivity of the planet for human use.
5. Changes in the composition of the atmosphere.
6. The damming of most of the world's rivers. Humans have extensively altered river systems through impoundments and diversions to meet their water, energy, and transportation needs. Today, there are > 45,000 dams above 15 m high, capable of holding back > 6500 km³ of water (1), or about 15% of the total annual river runoff globally. (Nillson et al, 2005).
7. The beginning of a massive extinction of life, about one species every 20 minutes (Wilson, 1992). One fifth of all species will be gone by 2030 if the present rate continues (Wilson, 2003: 102).
8. The total biomass of the world's population increased to roughly 40 megatons of carbon. To put this number into perspective, consider: The biomass of all life is roughly 500 Gigatons of carbon, the biomass of all wild vertebrates on land is roughly 5 megatons, and the biomass of all vertebrates in the ocean is about 50 megatons of carbon. We have eight time the mass of all wild land vertebrates, and about the same biomass as all the fish and whales in the ocean. Domesticated animals have a biomass of roughly 100 megatons of carbon. The biomass of our animals is about 20 times the mass of all wild vertebrates on land, and 50% larger than the mass of all vertebrates in the ocean. Smil (2002: 186, 283–284).
9. The mass of all motor vehicles is roughly 1,000 megatons. "Machines now need more carbon every year than humans do. The global food harvest now amounts to about 1.3 gigatons of carbon per year, whereas almost 1 gigaton of fossil carbon is used annually to produce metals and plastic from which machines are assembled, and about 4 gigatons of carbon are used each year to power them." Smil (2002: 269).
10. The ability to reach almost any point on land within 48 hours. "Wilderness? Only 10% of the land area is remote – more than 48 hours from a large city." Travel time to major cities: A global map of Accessibility.

But there is a theory by W. Ruddiman which states that we started very early with these global changes and that in essence that human foorprint kept us 6000 years ago out of an natural ice-age to come.
Read his pdf on early anthropceen

 

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