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Posted at 12:47 PM ET, 07/16/2012

Northern Hemisphere warmest on record, Arctic ice has biggest melt in June


Global temperatures in June ranked 4th warmest on record (over 133 years). Red dots indicate areas warmer than normal. Blue dots indicate areas cooler than normal. (NOAA)
Globally, June was 4th warmest on record, NOAA announced today. And over the Northern Hemisphere, for the second consecutive month, temperatures were as warm as they’ve been in 133 years of records. Notably, the Arctic experienced its largest June sea ice loss since the start of satellite records in 1979.

Link: June state of the climate report

It was the 36th consecutive June and 328th consecutive month with temperatures warmer than the 20th century average, NOAA said.

Across the globe, land areas were relatively warm compared to the oceans - in the midst of a transition from their cool (La Nina) to warm (El Nino) phase.

In the Northern Hemisphere, land areas were warmest on record for the third month in row - more than 2.34 degrees F above average.

While not at record high levels, the global average ocean temperature still ranked 10th warmest out of a pool of 133 years. In the Northern Hemisphere, the ocean temperature ranked 11th warmest.


Arctic sea ice extent in June ranked 2nd lowest on record (NOAA)
The decline of Arctic sea ice is one of the more telling indicators of recent warmth in the Northern Hemisphere. The Arctic lost the equivalent of 1.1 million square miles of ice in June (most on record), its extent falling to 9.8 percent below average, second lowest on record (since 1979).

Snow cover in the Northern Hemisphere, another indicator of temperature, reached its lowest extent in 45 years of June records (hat tip, Climate Central).

“Snow extent ... was more than 1 million square kilometers (386,000 square miles) below the previous record set in 2010,” said the National Snow and Ice Data Center:

[Running counter to Northern Hemisphere snow and ice indicators, Antarctic sea ice, was 2.5 percent above normal, 10th largest in the 34-year record. For quite a while, trends in Antarctic sea ice has gone against these global snow and ice indicators, likely linked to complex changes in ocean circulation in the region. Temperatures in that same region have warmed (see academic paper)]

For the year (January through June), global temperatures now rank 11th warmest on record. The greatest warmth, NOAA said, has concentrated over North America, southern Greenland, and Russia over these first six months.

But it hasn’t been warm everywhere.

“The first half of 2012 was notably cooler than average across Alaska, Mongolia, and Australia,” NOAA said.

Global warmth has generally increased as the La Nina event, associated with cool Pacific tropical ocean waters, has faded during the course of the year.

* January ranked 19th warmest
* February ranked 22nd warmest
* March ranked 16th warmest
* April ranked 5th warmest
* May ranked 2nd warmest
* June ranked 4th warmest


Evolution of global temperatures this year (black) compared to top 5 warmest years (NOAA)
With an El Nino event forecast to begin in the coming months, global temperatures relative to average have a good chance to remain among the top 5 warmest on record if not occupy the top two or three spots depending on El Nino’s strength and other evolving factors.

By  |  12:47 PM ET, 07/16/2012

Categories:  Latest, Climate Change

 
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