Monday, 22 September 2014

No El Niño but getting close to a record hot year for the planet anyhow

Of the world’s five warmest years on record – 2010, 2005, 1998, 2003, and 2013 – all but 2013 began during a mature El Niño event. Hence the interest always paid to this measure reflecting ocean water temperatures in the Pacific and to the speculation that 2014 might be another record high temperature one when the climate model makers earlier in the year were putting the chances of an El Niño at 80%. That probability has now retreated a little with the Australian Bureau of Meteorology’s latest El Niño watch being in the neutral range.
Somewhat surprisingly the warm temperatures have kept coming without an El Niño influence. According tothe latest report of the US National Oceanic and Atmospheric Administration (NOAA):
  • The combined average temperature across global land and ocean surfaces for August 2014 was record high for the month, at 0.75°C (1.35°F) above the 20th century average of 15.6°C (60.1°F), topping the previous record set in 1998.
  • The global land surface temperature was 0.99°C (1.78°F) above the 20th century average of 13.8°C (56.9°F), the second highest on record for August, behind 1998.
  • For the ocean, the August global sea surface temperature was 0.65°C (1.17°F) above the 20th century average of 16.4°C (61.4°F). This record high departure from average not only beats the previous August record set in 2005 by 0.08°C (0.14°F), but also beats the previous all-time record set just two months ago in June 2014 by 0.03°C (0.05°F).
  • The combined average global land and ocean surface temperature for the June–August period was also record high for this period, at 0.71°C (1.28°F) above the 20th century average of 16.4°C (61.5°F), beating the previous record set in 1998.
  • The June–August worldwide land surface temperature was 0.91°C (1.64°F) above the 20th century average, the fifth highest on record for this period. The global ocean surface temperature for the same period was 0.63°C (1.13°F) above the 20th century average, the highest on record for June–August. This beats the previous record set in 2009 by 0.04°C (0.07°F).
  • The combined average global land and ocean surface temperature for January–August (year-to-date) was 0.68°C (1.22°F) above the 20th century average of 14.0°C (57.3°F), the third highest for this eight-month period on record.
Now I know there is something magical about calendar year records but I have used NASA’s data to plot average monthly temperature anomalies for the 12 months to August and it too shows 2014 as the third highest on record
22-09-2014 averageaugustanomaly
The NOAA has catered for the calendar year followers with graphics comparing the year-to-date temperature anomalies for 2014 (black line) to what were ultimately the five warmest years on record: 2010, 2005, 1998, 2003, and 2013. Each month along each trace represents the year-to-date average temperature. In other words, the January value is the January average temperature, the February value is the average of both January and February, and so on.
The first graphic shows the basic year-to-date comparison. The second graphic zooms even further to what were ultimately the five warmest years on record, and shows several end-of-year results based on the following scenarios:
22-09-2014 scenario
The years 2013 and 2014 are the only years on this list not to begin during a mature El Niño event. The years 1998 and 2010, each of which became the warmest year on record at the time, ended the year in a strong La Niña event, as evidenced by the relative fading of global average temperature later in the year.
The anomalies themselves represent departures from the 20th century average temperature. The graph zooms into the warmest part of the entire history.
22-09-2014 yeartodatetemperatures
22-09-2014 globaltemperaturescenarios
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