The most recent geologic era (10,000 years to present) is traditionally known as the Holocene. Nobel Prize winning atmospheric chemist, Paul Crutzen, holds that mankind’s impact on the Earth in very recent centuries has been severe enough to merit a geologic era all of its own:

To assign a more specific date to the onset of the “anthropocene” seems somewhat arbitrary, but we propose the latter part of the 18th century, although we are aware that alternative proposals can be made (some may even want to include the entire holocene). However, we choose this date because, during the past two centuries, the global effects of human activities have become clearly noticeable. This is the period when data retrieved from glacial ice cores show the beginning of a growth in the atmospheric concentrations of several “greenhouse gases”... Such a starting date also coincides with James Watt’s invention of the steam engine in 1784.

Crutzen, P. J., and E. F. Stoermer. (2000) The "Anthropocene". Global Change Newsletter. 41: 12-13.

PAUL JOSEF CRUTZEN (1933- )

Dutch scientist who won the 1995 Nobel Prize in Chemistry (together with Mario Molina and F. Sherwood Rowland) “for their work in atmospheric chemistry, particularly concerning the formation and decomposition of ozone.”