October 29, 2010 | 1:46 PM | By

Cold Pacific skews global ocean temperatures

FILED UNDER: Ocean Change, sea surface temperature

I found this graph on Dr. Roy Spencer’s blog today:

As posted by Dr. Roy Spencer / www.drroyspencer.com

Deviation of 3-day (blue) and 40-day (black) global average sea surface temperatures from the long-term average. Moderate to strong La nina conditions in the Pacific are pulling down global average temperatures this year.

It was accompanied by a very brief post that posed the question “Bottom Falling Out of Global Ocean Surface Temperatures?” but provided almost no context. So I’ve taken it upon myself to add some. First and foremost, this does not contradict global warming.

Images by Jesse Allen, NASA's Earth Observatory, using Sea Surface Temperature data from the Advanced Microwave Radiometer for EOS (AMSR-E), courtesy Remote Sensing Systems.

Sea surface temperature anomalies for the month of September 2010. The equatorial Pacific is currently 1.5ºC below average (blue) due to La Nina, while other parts of the ocean are as much as 5ºC warmer than usual (red).

Indeed, many parts of the world’s oceans – like the North Atlantic – have been much warmer than usual this year. As Andy Freedman explains, these seemingly contradictory conditions are a symptom of a moderate to strong La ninã event that may have been the only thing keeping 2010 from even more record-setting heat:

The chief hallmark of La Nina is a region of cooler-than-average water temperatures in the central to eastern equatorial Pacific Ocean, extending down along the northwest coast of South America. The cooler waters and associated changes in airflow and precipitation patterns can significantly impact the world’s weather. La Nina can even cause a dip in global average temperatures, and the current event may keep 2010 from becoming the hottest year in the surface temperature record.