On 20/01/17 16:37, Vidcapper wrote:
On 20/01/2017 08:49, wrote:
On Thursday, 19 January 2017 07:13:44 UTC, vidcapper wrote:
On 18/01/2017 17:45, wrote:
https://data.giss.nasa.gov/gistemp/t...LB.Ts+dSST.txt

Record global temperatures for the 3rd year running. 2017 will
(OK, almost certainly will) show cooling from the 2016 figure,
however.


Why so confident?

--

Paul Hyett, Cheltenham

There isn't an El Nino at the start of the year, Paul, as there was
last year. Thus the world will be cooler. Instead we have La Nina
conditions to start the year. Comparisons between years are best made
between like to like years - though there are climate deniers who
will trumpet a cooler 2017 as evidence of global warming having
stopped/paused/was never happening anyway. Always happens *)).


I can understand why EN can increase the temperature in a local region,
but since it doesn't make the sun hooter for the whole year, how can it
raise the overall global temperature?


During an El Nino year, the air over the region is warmer than usual and
is transported polewards in the usual manner, thus warming the whole
globe. During El Viejo, the air over the Pacific equatorial regions
loses heat to the colder water so this coming year will be less warm. As
a possible pointer, the final three months of last year were each cooler
than the corresponding months for the previous year.

The ENSO is forecast to become neutral soon so, assuming that forecast
is correct (that's a big "if" going on past performances), then the
cooling of the atmosphere could be less than was seen after 1998 when El
Viejo persisted for more than two years and was stronger than the
current one. Also the PDO index was mostly negative for four years
following 1998 whereas now it remains positive.


--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
There are more fools than knaves in the world, else the knaves would
not have enough to live upon. [Samuel Butler]