Reply to Anthropocene Working Group responses

In 2015, the journal Science invited me to comment on the start of anthropogenic change. That request was likely related to the fact that the Anthropocene Working Group (AWG) of the International Commission of Stratigraphy was thinking of choosing a formal start date for the Anthropocene at or after 1950. Joined by three co-authors (Ruddiman et al., 2015), we emphasized the many near-global anthropogenic changes that preceded 1950 by centuries to millennia. Early in 2018, Progress in Physical Geography (PiPG) published a more extended critique of mine regarding this possible AWG action. I noted three flaws in choosing 1950 as the formal start date. In response to this challenge, the AWG recently submitted two draft papers to PiPG, one rebutting my 2018 paper (Zalasiewicz et al.), and one supporting and extending it (Edgeworth et al.). The first part of this reply elaborates on the flaws cited in my 2018 PiPG paper, incorporating comments from Edgeworth et al. The second part addresses the criticisms in Zalasiewicz et al.