The width of this slim bright side you talk about - is it epsilon? The harm done by ships travelling the northwest passge might outweigh any emission savings (

The width of this slim bright side you talk about - is it epsilon? The harm done by ships travelling the northwest passge might outweigh any emission savings (there - not in total). Carbon dioxide emissions are a rather non-localized problem while soot, spilled oil, invasive species, noise pollution and you name it, are very localized problems.