Nick has obfuscated the issue by misrepresenting the original article, by failing to provide the quotes from the original authors stating that the series could not be used for paleoclimate of the last millennium.
In a thread where all we have about a “new paper” is an abstract, no less.
Let’s see how this claim fares by looking at the relevant quote:
The multiproxy approach used in this study highlights the interplay of ontogenetic processes (e.g. marine isolation, catchment maturation, soil and lake development, plant colonization) with overarching climatic factors (e.g. early Holocene aridity, Neoglacial cooling). Anthropogenic influences, which began with the Norse colonization around 1000 AD, preclude paleo-climatic interpretation during the last millennium.
The authors do not state anything about “the series”. The sentence before “preclude” refers to their “multiproxy approach”. The paleo-climatic interpretation may very well refer to the multiproxy approach. According to this reading, what is precluded from a paleo-climatic interpretation during the last millenium is the multiproxy approach the authors use.