On a global scale it was the coldest June in 5 years as well, especially across North America, Eastern Europe, Southern Russia and Australia. This would suppress demand for hot weather items in the northern hemisphere regions, but a plus for Winter seasonal items in Australia. The heat was most excessive in India where drought was extreme with the driest June in India in over 20 years.
The cooler global trends were the result of 4 large scale features:
1. Pacific Decadal Oscillation (PDO) Cycle, 32-year cold phase of the Pacific Ocean started 2 years ago and continues for the next 30 years. It will be interrupted by a developing El Nino (warmer ocean in the tropical Pacific) this year and early next year which could lead to a warmer 2010 here in the U.S.
2. Atlantic Ocean Multi-decadal Oscillation (AMO) Cycle, the 20-year cold phase of the Atlantic Ocean started this year - several years earlier than normal. Colder Atlantic Ocean = colder planet.
3. Very long solar minimum cycle that is now the longest 100 to 300 years. Weak sun = less solar radiation (heat) here on Earth = cooler planet.
4. Eruption of Russian volcano Sayrchev Peak on June 12th. Large volcanic eruptions spew massive amounts of SO2 (sulfur dioxide) into the upper atmosphere which actually reflects incoming solar radiation. Since this volcano was in the Northern Hemisphere it can have an even greater impact on our temperatures (cooler).
The official global temperature anomaly from the University of Alabama showed a dramatic warming trend from the 1970s to 1998 which corresponded to the warm phases of the PDO and AMO ocean cycles. Since both have flipped cold in the past two years a more dramatic cooling trend has developed that is getting little media attention. While the globe was cooler, some areas such as India and the UK had scorching heat-waves.
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