Global Environmental Changes Spark Debate on Anthropocene listen06/16/11 Matthew Cimitile
WMNF Drive-Time News Thursday | Listen to this entire show:
Biodiversity loss, climate change, deforestation, and plastic pollution are just some of the global environmental issues stemming from human activity that are leaving a definitive mark on the planet. Such a mark in fact, that it has spurred debate among geologists whether the rapid changes taking place right now deserve its own geologic designation called the Anthropocene or age of man. Ben Flower is a marine geologist for the College of Marine Science at the University of South Florida.
â€œWell the epochs have always been defined by major changes in biota and climate and often sea level. And we currently are undergoing major changes in all three. Changes in biota, there are major extinctions that are ongoing right now, changes in climate that are just beginning and changes in sea level that are just beginning. So it fits with the criterion that major environmental change is noted by a designation of a new epoch.â€
All epochs have been caused in the past by natural processes such as changes in ocean circulation or the movement of tectonic plates. Peter Harries, a paleontologist at the University of South Florida, says if the Anthropocene is added to the geologic time scale it would not follow suit.
â€œThe difference would really be that this would be the first event that is triggered by a single species. So in that sense that is why the Anthropocene is named that, anthro for human, and cene for interval. You have a species which it has reached a point where it is dominating and able to manipulate all the spheres that we talk about, the hydrosphere, the biosphere, the atmosphere. Has the ability to profoundly affect all of those.â€
Though the source of the large scale changes taking place may be different from those that occurred in the past, one thing will remain the same. Millions of years from now, said Flower, future geologists will be able to discern the new epoch in rocks and sediment.
â€œThe extent of the extinctions on land and in the ocean will leave a permanent record in those archives. In addition, ocean acidification is going to leave a further mark in calcium carbonate sediments which will dissolve as a result of the increased acidity of the ocean.â€
According to the Center for International Earth Science Information Network, 83 percent of Earthâ€™s land surface is influenced directly by human beings. An over abundance of carbon dioxide in the atmosphere is warming the planet and acidifying the oceans, and the extent of biodiversity loss currently underway has the potential to become the sixth wave of mass extinction.
Some geologists however, argue that it is too soon to designate a new epoch. Harries explained changes so far do not replicate the magnitude of changes in the past and the large-scale changes generated from humans are likely still to come.
â€œTo a certain degree when youâ€™re in something it always looks a little different. Clearly there has been a lot going on but it seems like it may be a bit premature to say this is where the Anthropocene boundary is. I would suggest if humans do indeed end up producing a 6th mass extinction, the boundary should logically be there, following the termination of that extinction.â€
A working group of the International Commission on Stratigraphy aims to determine whether the Antropocene deserves to be incorporated into the geologic time scale. The process will likely take many years. But Flower said the important thing is that the debate makes people discuss and understand the fundamental changes humans are creating on Earth today.
â€œWhether or not it is designated as a formal epoch, the fact remains that the scale of change humans are responsible for inflicting on the environment does approach natural changes that we know about in the past, specifically at epoch boundaries. The end of the Pleistocene and the beginning of the Holocene that transition was marked by about a 5 degree change in global temperature and about 120 meters worth of sea-level rise. Those are a lot higher values than what weâ€™re talking about for base of the proposed Anthropocene epoch, but the rates of change are actually quite comparable and in the case of the recent record some of them are a lot higher and that is a big part of the reason why organisms are suffering.â€