If global warming has stalled, and 1998 was an El Nino year, why is 2007 as warm as 1998?

Question

To be fair, in all likelihood 1998 is going to be a tiny bit warmer than 2007. However, 1998 was an unusually warm El Niño-Southern Oscillation year

http://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillation

On the other hand, in 2007 the southern oscillation was in a cool phase.

"The natural variations of the Southern Oscillation and the solar cycle thus have minor but not entirely insignificant effects on year-to-year temperature change. Given that both of these natural effects were in their cool phases in 2007, it makes the unusual warmth this year all the more notable. It also suggests that, barring the unlikely event of a large volcanic eruption, a record global temperature exceeding that of 2005 can be expected within the next 2-3 years."

http://www.columbia.edu/~jeh1/mailings/20071210_GISTEMP.pdf

If global warming has "stalled" as some skeptics claim, then why wasn't 2007 much colder than 1998, considering these variations in the El Niño-Southern Oscillation?

Tomcat - the most recent El Nino event ended early this year. The rest of the year was a weak La Nina event.

http://en.wikipedia.org/wiki/El_nino

Voice - see above (or below)

"The most recent occurrence of El Niño started in September 2006[3] and lasted until early 2007.[4]. From June 2007 on, data indicated a weak La Niña event."

http://www.cbsnews.com/stories/2007/02/28/tech/main2523483.shtml

As you can see in the link above, El Nino lasted slightly less than 2 months in 2007. I'd hardly call that an "El Nino year", especially since we've been in a La Nina event since June.

Answer 1

Twelve months ago I would have predicted 2007 as being one of the three hottest years on record with a reasonable possibility that it would be the hottest. Such a prediction being based on underlying warming trends and the effect of ENSO in 2007.

The year got off to a flying start, January 2007 was the hottest month ever recorded, if that had have continued throughout the year then 2007 wouldn't have broken the existing records it would have smashed them. According to the GISTemp temperature record, January was 1.09°C warmer than the long term mean, the only other occasion that any month had an anomalous value greater than 1°C was in Feb 1998 when the temp was 1.01°C above the long term mean (GISTemp figures).

February was another exceptionally warm month and everything was going as predicted, then the ENSO effect weakened unexpectedly and temps fell back more or less in line with the underlying warming trend. Consequently, as the year progressed, the anomalous value for 2007 decreased and it became 'just another warmer than average year'.

Interestingly, when ENSO weakened, revised predictions for the year were made and these have proved to be remarkably accurate. In approx March / April, myself and others predicted an average global temp for 2007 of around 14.6°C, the current average figure is 14.5973°C, so with the exception of ENSO, it's gone as predicted.

The data aren't yet in for all of 2007 but at the moment this is how it stands...

According to GISTemp it's the second hottest year on record, beaten only by 2005. Certain skeptics love to quote from GISTemp as this is the temp record that shows 1934 as being the hottest year in the US (48 contiguous states). If they're to be consistent then they have to accept that 1998 is not the hottest year on record.

Going by HADCrut3 then 2007 is the 7th warmest year on record (beaten by 1998, 2005-3-2-4-6) and taking an average of different temperature records then it's the thrid warmest year on record (beaten by 1998 and 2005).

Here's the data http://profend.com/gtr/ (apologies for not yet having uploaded November's data, will do soon, the addition of the Nov data moves 2007 into 7th place as per HADCrut3 but changes little else).

The underlying temperature trend is one of continually rising temperatures, had 1998 not being affected by ENSO then it would have been an unremarkable year. Here's a graph showing the 5, 10 and 30 year means, as you can see, the trend is one of consistently increasing temperatures. http://profend.com/gtr/graphs/meangraphave.html

Answer 2

Actually, 2006-2007 is listed as an El Nino period, as was 1997-1998. 2007 global temperatures will be very close to those in 1998, but below those in 2005, which was not during an El Nino period. The five year global temperature trend line will certainly show a leveling effect as there has been no statistically significant increase in global temperatures for the past 10 years or so. This does not, however, mean that the warming trend is over. If you review past data, you can see where there were several levelings or even reversals in the five year trend line.

Answer 3

Sooner or later, someone is going to claim it's because the Pacific Decadal Oscillation is in the wrong phase for la Nina to produce cooler conditions.

I don't believe that, but someone is going to claim it. :-)

The figures in Hansen et al. you provide links to are interesting because they show a boreal and austral polar amplification of the warming signal. The "lack" of an austral warming gets trumpeted a lot as a sign that climate models are wrong, therefore the whole theory can't be true. However, since there clearly is austral warming, maybe we will stop hearing that argument.

Nah.

Answer 4

Could it be that 2006 and 2007 were both El-Nino years?

Answer 5

A most clear and enlightening set of information there.

I think the answer to your question could be

" AGW is in fact , correct"

- as most intelligent people have realized all along.

edit: and for gods sake people, "Global Warming" does not just mean " its always hot" its simply another name for " climate change" -i.e the climate changes, NOT its always hot. Its simply means the the GLOBAL average temp goes up. It does not stop cold weather. For heavens sake go back to school or SOMETHING.

Answer 6

Its freezing here in Sydney Australia ,maybe it will be hotter in January?.GW is very real wait until next year,and the year after that.

Answer 7

I don't know about you, but it's FREEZING here.

Seriously, accept the Earth as she is. Adapt or refuse to adapt and deal with the consequences. The Earth will continue out of the end of the current ice age and into a warmer period. It's her natural cycle. Humans shouldn't attempt to stop her just because we selfishly want to keep things the way they are.

We need to learn to embrace the Earth and not to try to control her. Ice ages come and go. It's happened before and it will happen again, even if we humans don't like it.

Answer 8

No Dana, it's freezing out where I live. uuuummmm.....doesn't that mean that GW doesn't exist???

Regards,

A person who doesn't know jack about anything!

P.S.: can I borrow your car?