Guest post by Frank Lansner
A global temperature stagnation despite warm El Nino year 2010?
After the warm El Nino period 2009-2010, global temperature trends starting 1998 has generally turned positive:
The period starts out with a strong El Nino in 1998, however a strong La Nina lasting 3 times longer also has a strong effect on temperature trends starting 1998.
Temperature trends from 2002:
Thus removing the 1998 El Nino and 1999-2001 La Nina significantly cools the trends. The overall picture is now temperature stagnation 2002-2010 9 years.
The global warming theory generally suggests heating, but one can say that a period of roughly a decade with no temperature rise might be an expected deviation from the general trend.
However, things get worse for the global warming idea. Problem is that 2010 in the very end of the shown period is in fact a rather warm El Nino year. And still, the trends 2002-2010 are just… flat. Even now after the warm 2010. As if the global warming idea just barely holds on in the months just after a warm 2010.
However, things get even worse for the global warming idea. The powerful La Nina is now showing its strength as we have witnessed temperature dive in the latest months. The NCEP prognoses roughly indicates a further drop of probably more than 0,1 K from dec 2010 to jan 2011. And the La Nina – allthough predticed to weaken during spring time – is by many predicted to match the 1999-2001 La Nina.
IF the present La Nina will resemble the magnitude and effect of the 1999-2001 La Nina, how would this affect the temperature trends from 1998 that already seems to have stagnated for a decade?
A “simulated” La Nina 1999-2001 by just assuming the same temperature flow repeated starting Januar 2011 to get a rough idea. Now suddenly we have a full 16 years period of no warming. In fact we mostly see cooling trends. (If we imagine yet an El Nino to occur thereafter, then after 17 – 18 years, perhaps we will still just have a flat curve??)
And “Uhh Ohh” whats going to happen if we simulate a 1999-2001 La Nina on the graph starting at 2002??
In this view, we see 12 yeas of strongly falling temperature trends.
La Nina is upon us, and that it won’t help the global warming message.
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Method used above is basically saying:
“How many years can we go back and still see temperature trend stagnation or trend decline?”
If we want to have an answer to this question, typically the year 1998 or 2002 will be the start year of the new stagnating (or falling) temperature trend.
The classic alarmist argument is then: But we have had 5 year, 7 year and 8 year trends before without the longer warm trend has changed.
This is true, however, these dives in temperatures are almost always connected with the large volcanic eruptions as Lucia from the Blackboard here shows:
So, when we use 1998 or 2002 as start years, and only thereby can read the length of the present stagnating/falling temperature trend, we have to know: This time there are no volcano to blame.
And when the result – for example after the La Nina prognosis shown above – may give us 12-15-18 years of stagnating/falling trends – without the help of volcanoes – then this IS something significant against anything we have seen in the last decades of warming.
And without using start years 1998 or 2002 we cant tell how many years the falling trend this time is. Therefore its perfectly relevant to use 1998 or 2002 as start years.
And as fig 2 here indicates
the 1998 El Nino may have lifted the whole temperature level (perhaps by warming the Arctic) and in this context, it is definitely relevant to analyse using start point 1998.
There are many ways of defining how the temperature trend is best described, but the idea that we had a level shift in temperature 1998 too makes it relevant to checkout trends after 1998 red dotted line:
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