84 degrees near the Arctic Ocean this weekend as carbon dioxide hit its highest level in human history

Saturday's 84-degree reading was posted in Arkhangelsk, Russia, where average high temperature is 54 this time of year. The city sits next to the White Sea, feeding into the Arctic Ocean's Barents Sea. At Arkhangelsk, it was hotter on Sunday: 87. Locations in Russia set record-high temperatures over the weekend: 30 to 40 degrees above average. The warmth bled west into Finland at 77 degrees Saturday, the warmest temperature of the season. Abnormally warm conditions in this region stemmed from a bulging zone of high pressure centered over western Russia. This heat wave, a manifestation of the arrangement of weather systems and fluctuations in the jet stream, fits into what has been  hot year across the Arctic and most of the mid-latitudes.  In Greenland the ice sheet's melt season was a month early. In Alaska, several rivers saw winter ice break up on their earliest dates on record.