[Vision2020] AGU: Developing La Nina Cools the Planet in September

[Ted Moffett]

http://blogs.agu.org/wildwildscience/2011/10/17/developing-la-nina-cools-the-planet-in-september/

http://blogs.agu.org/wildwildscience/files/2011/10/201109sigclim.gif

17 October 2011

Developing La Nina Cools The Planet in September

Dan Satterfield

The developing La Nina in the Pacific has brought the global
temperature in September down slightly, but it was still the 8th
warmest on record. NASA does a separate calculation and ranks Sep.
2011 as 9th warmest. When a La Nina develops the world’s largest ocean
sees noticeably cooler surface waters.  This chills the air enough to
bring the global temperatures down, while El Nino does  just the
opposite. The super El Nino in 1998 still ranks as one of the hottest
years recorded on the planet since reliable temp. records began.

Keep in mind that this is a natural fluctuation on top of the steadily
increasing forcing from greenhouse gases, so in spite of the La Nina
cooling the planet some, this past September was still ranked as the
8th warmest on record. Some more on the global temps from NCDC here:

The January – September worldwide land surface temperature was 0.80°C
(1.44°F) above the 20th century average — the 7th warmest such period
on record. The margin of error is +/- 0.20°C (0.36°F). The global
ocean surface temperature for the year to date was 0.41°C (0.74°F)
above the 20th century average and was the 12th warmest such period on
record. The margin of error is +/- 0.04°C (0.07°F).

The combined global land and ocean average surface temperature for
September 2011 was the eighth warmest on record at 15.53°C (59.95°F),
which is (0.53°C) 0.95°F above the 20th century average of 15.0°C
(59.0°F). The margin of error associated with this temperature is +/-
0.11°C (0.20°F).
Separately, the global land surface temperature was 0.87°C (1.57°F)
above the 20th century average of 12.0°C (53.6°F), making this the
fourth warmest September on record. The margin of error is +/- 0.24°C
(0.43°F).
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Vision2020 Post: Ted Moffett