The reply from Jean (no I'm not talking to myself - though that has been known to happen:-)

During my work on this arctic paper I was shocked by the variable definition of arctic, being either due to obliquity of the earth or temperature.

Ray Leonard former VP E Yukos told me that in Russia, workers are paid double when working north of 60° and do not want to work south. So the northern part is more explored. I checked my files of exploratory wells in Russia and there are about 1000 wells from 60° and 60° 30' but only 350 wells from 59°30 and 60°. It is obvious that north of 60° is more explored than the south!

Maybe the Russians can do horizontal drilling from above 60 degrees to produce the oil between 59 30 and 60.

Maybe the Russians can do horizontal drilling from above 60 degrees to produce the oil between 59 30 and 60.

North of 60 is closer to the coast. Coastal shipping part of the year is easier in Russia than in Alaska and Canada. This might explain why north of 60 is more explored in Russia.