"Proof" of manmade global warming debunked

We reported here about a new study by Yarrow Axford that "proved" that the warming in the last 50 years was unusual and man-made. The study relies on investigating midge larvae in sediment cores on Baffin Island as a proxy for temperature. Watts Up With That has posted several rebuttals, including this latest one:

As I’ve pointed out on WUWT several times, the study is terribly flawed, because they haven’t considered other possible factors, such as DDT and other pesticides being transported into the lake from nearby military outposts and settlements, plus the tendency for transport or organotoxins into glacial ice which ends up in meltwater lakes. Plus the nearby weather station shows no significant warming.

WUWT reader “Ecotretas” points out this July 2009  peer reviewed study Evidence for a warmer period during the 12th and 13th centuries AD from chironomid assemblages in Southampton Island, Nunavut, Canada by Nicholas Rolland et al, which uses the same techniques, but just one island west of Baffin… The Rolland et al study temperature reconstruction shows a significantly different result than that of Axford.

Read it here.