The Age of Man: A New Geologic Epoch
For the past 250 years, humans have released billions of tons of carbon dioxide (CO2) into the atmosphere, primarily by burning fossil fuels like coal and oil. Now, scientists say the impact of all this CO2 and other human activities on the natural world is so significant that it constitutes a new period of geologic time in the planet's history. This new proposed epoch, the Anthropocene — so named to represent the human-dominated influence — is marked by measurable changes in the Earth's climate, geography and biological composition. These changes are akin, they say, to the great extinctions and ice ages that previously signified transitions between geologic periods or epochs now visible in layers of ancient rock.
For the first time, humans are attempting to denote a new geologic epoch as they live through it, and in a new issue of the Philosophical Transactions of the Royal Society A many scientists contend the planet's environment has already met the criteria for a newly-designated epoch. Moreover, in the March 2011 issue of National Geographic, journalist Elizabeth Kolbert writes about the Anthropocene and what types of human activity are expected to have a long-lasting impact on the planet, from a geologic perspective.
Though the building of skyscrapers, extensive deforestation and expansion of agriculture have all changed our current landscape, in terms of future geology, these activities won't have as much of an impact as the burning of fossil fuels. Kolbert writes:
Probably the most significant change, from a geologic perspective, is one that's invisible to us — the change in the composition of the atmosphere. Carbon dioxide emissions are colorless, odorless, and in an immediate sense, harmless. But their warming effects could easily push global temperatures to levels that have not been seen for millions of years. Some plants and animals are already shifting their ranges toward the Poles, and those shifts will leave traces in the fossil record. Some species will not survive the warming at all. Meanwhile rising temperatures could eventually raise sea levels 20 feet or more.
Long after our cars, cities, and factories have turned to dust, the consequences of burning billions of tons' worth of coal and oil are likely to be clearly discernible