Debate on Unit Roots in Temperature Series

A huge debate with 1672 comments erupted on Bart Verheggen's blog regarding the issue of unit roots in temperature series. I didn't read much of it, but the main point seems to be that when there are unit roots in time series you need to take that in account when determining if there is a trend in the series and it is harder to reject the null of no trend. This is all true but you can also