Second warmest June on record
The globe recorded its second warmest June on record, 0.02°C short of the record set in 2005, according to the National Climatic Data Center. The period January - June was the fifth warmest such period on record. Global temperature records go back to 1880. The most notable warmer-than-average temperatures were recorded across parts of Africa and most of Eurasia, where temperatures were 3°C (5°F) or more above average. The global ocean Sea Surface Temperature (SST) for June 2009 was the warmest on record, 0.59°C (1.06°F) above the 20th century average. This broke the previous June record set in 2005. The record June SSTs were due in part to the development of El Niño conditions in the Eastern Pacific. If El Niño conditions continue to strengthen during the coming months, we will probably set one or more global warmest-month-on-record marks later this year. The last time Earth experienced a second warmest month on record was in October 2008.
June sea ice extent in the Arctic 4th lowest on record
June 2009 Northern Hemisphere sea ice extent was the 4th lowest since 1979, according to the National Snow and Ice Data Center. The record June low was set in 2006. This summer's melt is lagging behind the melting in the summer of 2007, which set the record for the lowest amount of summer sea ice in the Arctic. Forecasts of summer Arctic sea ice melt made in early June by two teams of German scientists put the odds of a new record sea ice minimum this year between 7% and 28%. With the amount of sunlight in the Arctic now on the wane, it appears unlikely that we will set a new record sea ice minimum in 2009. This year will probably have the 2nd or 3rd least sea ice extent on record come September, when the melting season ends. The ice-free seas that nearly surround Greenland now have contributed to temperatures of 2 - 3°C above average over the island over the past ten days. With clear skies and above-average temperatures likely over most of the island for at least the next week, we can expect near-record July melting over portions of the Greenland Ice Sheet this month.
Northwest Passage likely to open for the third consecutive year
The fabled Northwest Passage is more than half clear now, and has a good chance of melting free for the third consecutive year--and third time in recorded history. The first recorded attempt to find and sail the Northwest Passage was in 1497, and ended in failure. The thick ice choking the waterways thwarted all attempts at passage for the next four centuries. Finally, in 1905, Roald Amundsen completed the first successful navigation of the Northwest Passage. It took his ship two-and-a-half years to navigate through narrow passages of open water, and his ship spent two cold, dark winters locked in the ice during the feat.
We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships (Walsh and Chapman, 2001). It is very unlikely the Passage was open between 1497 and 1900, since this spanned a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this time. The Northwest passage may have been open at some period during the Medieval Warm Period, between 1000 and 1300 AD.
That is, assuming that model was at all accurate.
