August 2012 global temperatures were fourth highest on record

News
Sep 28, 2012
by WLJ

The globally-averaged temperature for August 2012 marked the fourth warmest August since record keeping began in 1880. August 2012 also marks the 36th consecutive August and 330th consecutive month with a global temperature above the 20th century average.

Most areas of the world experienced much higher than average monthly temperatures, including far northeastern North America, central and southern Europe, and east-central Asia.

Meanwhile, parts of Siberia were notably cooler than average. In the Arctic, sea ice extent averaged 1.82 million square miles, resulting in the all-time lowest August sea ice extent on record. On Aug. 26, the Arctic dipped below the record smallest daily extent, previously set on Sept. 18, 2007.

The equatorial Pacific Ocean continued to reflect neutral El Nino-Southern Ocean, or ENSO, conditions in August. However, according to the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center, the El Nino warm ocean phase will likely develop during September. In addition to influencing seasonal climate outcomes in the U.S., El Nino is often, but not always, associated with global temperatures that are above the average trend.

August global temperature highlights

The combined average temperature over global land and ocean surfaces for August was the fourth highest on record for August, at 61.22°F (16.22°C) or 1.12°F (0.62°C) above the 20th century average. The margin of error associated with this temperature is ±0.16°F (0.09°C).

August 2012 Blended Land & Sea Surface Temperature Anomalies in °C August marked the 36th consecutive August and 330th consecutive month with a global temperature above the 20th century average. The last below-average temperature August was August 1976 and the last below-average temperature month was February 1985.

The global land temperature tied with 2001 and 2011 as the second warmest August on record, behind 1998, at 1.62°F (0.90°C) above the 20th century average of 56.9°F (13.8°C). The margin of error is ±0.32°F (0.18°C).

Higher than average monthly temperatures were most notable across far eastern Canada, southern Greenland, central and southern Europe, western Kazakhstan, Japan, western Australia, and Paraguay, while temperatures were much cooler than average across parts of Siberia.

The average August daytime (maximum) temperature across Australia was 1.49°C above normal, making this the sixth warmest August since national records began in 1950. Conversely, it was colder than average at night. The average nighttime (minimum) temperature across Australia was 0.83°C below average, making the difference between the average daytime temperature and the average nighttime temperature the greatest on record for August and third highest for any month on record.

The average monthly temperature in New Zealand during August was 1.2°C above average.

Austria reported its fourth warmest August since national records began in 1767, with a temperature that was 1.9°C above the long-term average, leading to the third earliest complete snowmelt on Aug. 19 at the high-elevation mountain station in Sonnblick.

Spain reported two heat waves in August that led to its second warmest August since its records began in 1961, behind only August 2003, at 2.0°C above average.

For the ocean, the August global sea surface temperature was 0.94°F (0.52°C) above the 20th century average of 61.4°F (16.4°C), or fifth warmest August on record. This was also the highest monthly global ocean temperature departure from average for any month since July 2010. The margin of error is ±0.07°F (0.04°C).

Neutral conditions continued during August across the central and eastern equatorial Pacific Ocean, with sea surface temperatures trending toward 0.9°F (0.5°C) above average for a threemonth period, the official threshold for the onset of El Niño conditions. According to NOAA’s Climate Prediction Center, El Niño conditions will likely emerge during September.

August polar ice highlights

August 2012’s Arctic sea ice extent averaged 1.82 million square miles, which was 38.5 percent below the 1979 to 2000 average. During the month, the Arctic lost an average of 35,400 square miles of ice per day, the fastest rate ever observed for the month of August, resulting in the all-time smallest August Arctic sea ice extent on record.

Arctic and Antarctic sea ice extent, from the August 2012 Global Snow & Ice Report

According to the National Snow and Ice Data Center, Arctic sea ice shrank to 1.58 million square miles on Aug. 26, dipping below the smallest extent on record, which occurred on Sept. 18, 2007, at 1.61 million square miles. By the end of the month, sea ice extent dropped to 1.42 million square miles, with the melt season expected to last until mid-September. All of the six lowest sea ice extents have occurred in the past six years.

On the opposite pole, Antarctic sea ice during August 2012 was 1.6 percent above average and ranked as fourth largest August extent in the 34-year period of record.

August precipitation highlights

In the north Atlantic, Hurricane Isaac brought locally heavy rain to Hispaniola, Cuba, and parts of the southeastern U.S., with some areas receiving up to 20 inches (500 mm) of rain.

In the western Pacific, a record three typhoons—Haikui, Saola, and Damrey— made landfall along China’s coast within a one-week period during late July and early August.

August was dry across most of Australia, with the country as a whole reporting its fifth driest August since national precipitation records began in 1900, with monthly rainfall just 44 percent of average. The last month with a national average deficit this great was March 2009.

The high-pressure systems that led to heat waves in Spain also contributed to a dry August. Spain reported its third driest August since national records began in 1961, with average precipitation just above one third of normal.

June-August global temperature highlights

The combined average temperature over global land and ocean surfaces for June- August tied with 2005 as the third highest on record for this period at 61.25°F (16.24°C), or 1.15°F (0.64°C), above the 20th century average of 60.1°F (15.6°C). The margin of error associated with this temperature is ±0.16°F (0.09°C).

The global land temperature was the all-time warmest June-August on record, at 1.85°F (1.03°C) above the 20th century average of 56.9°F (13.8°C). The margin of error is ±0.27°F (0.15°C).

For the ocean, the June- August global sea surface temperature was 0.90°F (0.50°C), above the 20th century average of 61.5°F (16.4°C), tying with 1997, 2001 and 2002 as the seventh warmest for June-August on record. The margin of error is ±0.07°F (0.04°C).

Year-to-date global temperature highlights

Record to near-record warmth over land from April to August and increasing global ocean temperatures in the eastern equatorial Pacific Ocean resulted in the first eight months of 2012 tying with 2006 as the ninth warmest such period on record, with a combined global land and ocean average surface temperature of 1.01°F (0.56°C) above the 20th century average of 57.3°F (14.0°C). The margin of error is ±0.18°F (0.10°C).

Year-to-date temperatures by month, with 2012 compared to the five warmest years on record

The January-August worldwide land surface temperature was 1.71°F (0.95°C) above the 20th century average, marking the sixth warmest such period on record. The margin of error is ±0.38°F (0.21°C).

The global ocean surface temperature for the year to date was 0.76°F (0.42°C) above average and ranked as the 11th warmest such period on record. This was the warmest monthly departure from normal since August 2010. The margin of error is ±0.07°F (0.04°C). — National Oceanic and Atmospheric Administration

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