NOAA's Global Climate Summary for 2012 was published this week. A link to the full report is posted at the end of this blog entry. It was basically another in a string of very warm years overall--and this in spite of La Nina (cool Pacific Ocean) being in effect the first quarter of last year.
The first paragraph has a couple striking details: The annual world combined land and ocean surface temperature more than a full degree Fahrenheit above the 20th century average is a huge jump when you consider the size of the earth's surface. And note that so far in the 21st century, every single year has had temperatures which rank among the 14 warmest in the 133-year period of record.
• The year 2012 was the 10th warmest year since records began in 1880. The annual global combined land and ocean surface temperature was 0.57 deg Celsius (1.03 deg Fahrenheit) above the 20th century average of 13.9 deg C (57.0 deg F). This marks the 36th consecutive year (since 1976) that the yearly global temperature was above average. Currently, the warmest year on record is 2010, which was 0.66 deg C (1.19 deg F) above average. Including 2012, all 12 years to date in the 21st century (2001–2012) rank among the 14 warmest in the 133-year period of record. Only one year during the 20th century—1998—was warmer than 2012.
•Separately, the 2012 global average land surface temperature was 0.90 deg C (1.62 deg F) above the 20th century average of 8.5 deg C (47.3 deg F) and ranked as the seventh warmest year on record.
•La Nina, which is defined by cooler-than-normal waters in the eastern and central equatorial Pacific Ocean that affect weather patterns around the globe, was present during the first three months of 2012. The weak-to-moderate La Nina dissipated in the spring and was replaced by ENSO-neutral conditions for the remainder of the year. When compared to previous La Nina years, the 2012 global surface temperature was the warmest observed during such a year; 2011 was the previous warmest La Nina year on record.
•The 2012 global average ocean temperature was 0.45 deg C (0.81°F) above the 20th century average of 16.1 deg C (60.9 deg F) and ranked as the 10th warmest year on record. It was also the warmest year on record among all La Nina years. The three warmest annual ocean surface temperatures occurred in 2003, 1998, and 2010—all warm phase El Nino years.
•Following the two wettest years on record (2010 and 2011), 2012 saw near average precipitation on balance across the globe. However, as is typical, precipitation varied greatly from region to region.
The year 2012 was the 10th warmest year since records began in 1880. The annually-averaged temperature across global land and ocean surfaces was 0.57 deg C (1.03 deg F) above the 20th century average. Record to near-record warm land surface temperatures in the Northern Hemisphere from April to September and overall warmer-than-average ocean surface temperatures made the first 11 months of the year the eighth warmest January–November on record. However, extreme cold across much of the Northern Hemisphere land during December helped lower the year-to-date temperature departure from average by 0.02 deg C (0.04 deg F) compared with the previous month.
Year-to-date temperatures by month, with 2012 compared to the five warmest years on record
2012 marks the 36th consecutive year (since 1976) that the annual temperature was above the long-term average. Currently, the warmest year on record is 2010, which was 0.66 deg C (1.19 deg F) above average. Including 2012, all 12 years to date in the 21st century (2001–2012) rank among the 14 warmest in the 133-year period of record. Only one year during the 20th century—1998—was warmer than 2012. The global annual temperature has increased at an average rate of 0.06 deg C (0.11 deg F) per decade since 1880 and at an average rate of 0.16 deg C (0.28 deg F) per decade since 1970.
Top 10 Warmest Years (1880–2012)
The following table lists the global combined land and ocean annually-averaged temperature rank and anomaly for each of the 10 warmest years on record.
1 = Warmest
Period of Record: 1880–2012 Year Anomaly Deg C Anomaly Deg F
1 2010 0.66 1.17
2 2005 0.65 1.17
3 1998 0.63 1.13
4 2003 0.62 1.11
5 2002 0.61 1.10
6 (tie)* 2006 0.59 1.07
6 (tie)* 2009 0.59 1.07
6 (tie)* 2007 0.59 1.06
9 2004 0.58 1.04
10 2012 0.57 1.03
*Note: Tie is based on temperature anomaly in °C.
Natural climate patterns that persist for days, months, or even years can affect weather patterns around the world and impact the average global temperature. One such well-known global-scale pattern—the El Nino-Southern Oscillation (ENSO)—is a natural episodic fluctuation in sea surface temperature (El Nino) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean. Over a period of months to a few years, ENSO fluctuates between warmer-than-average ocean surface waters (El Nino) and cooler-than-average ocean surface waters (La Nina) in that region.
2012 ranked as the warmest "La Nina year", surpassing the previous record set in 2011. Two of the three warmest years on record (2010 and 1998) are "El Nino years". A La Nina (El Nino) year is defined here as occurring when the first three months of a calendar year meet the La Nina (El Nino) criteria as defined by the Climate Prediction Center.
Full Report: http://www.ncdc.noaa.gov/…
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