The Science section this week in the New York Times takes a very big picture look at human impact on the earth, putting in terms of geological time:
Welcome to the “Anthropocene” — a new epoch in our planet’s 4.5 billion year history. Thanks to the colossal changes humans have made since the mid-20th century, Earth has now entered a distinct age from the Holocene epoch, which started 11,700 years ago as the ice age thawed. That’s according to an argument made by a team of scientistsfrom the Anthropocene Working Group. Scientists say an epoch ends following an event – like the asteroid that demolished the dinosaurs and ended the late Cretaceous Epoch 66 million years ago – that altered the underlying rock and sedimentary layers so significantly that its remnants can be observed across the globe. In a paper published Thursday in Science, the researchers presented evidence for why they think mankind’s marks over the past 65 years ushered in a new geological time period. Here are a few examples:Modern Agriculture
In the last century, fertilizers used in crop production doubled the amount of nitrogen and phosphorus in the soil. Signals of these chemicals found within lake strata are now at their highest levels in the past 100,000 years.
Aluminum. Concrete. And much more that we had not considered the full impact of, but is made more clear in this survey. Read the whole article here.