A heated debate: Paul Crutzen's word

Some think it fitting, others absurd.

Human-cleared farmland, ocean pH,

Nutrient cycling ... is this a new age?

No meteor crash, no huge plates have rifted,

But Earth's surface changed, and species have shifted.

This week in London, a group is convening,

These "geo"-based boundaries ... what is their meaning?

http://www.nature.com/nature/journal/v473/n7347/full/473254a.html?WT.ec_id=NATURE-20110519

http://www.nature.com/news/2011/110510/full/473133a.html#B2