Friday, 22 January 2016

What did El Nino 2015 Contribute to the 'Hottest Year Ever'?

There's been quite a lot of excitement in the media and on Twitter following announcements by NASA and the Met Office that 2015 was the hottest year ever recorded 'by some measure'. In particular, the debate has centred around how much El Nino contributed to the 'record hot year' (not evident at all in the lower troposphere satellite data) and how much man-made global warming was responsible. Given that global mean temperatures usually show a delay of several months after El Nino peaks, it seems reasonable to suppose that 2016 will peak higher than 2015.
So, we might expect that in 2015 the contribution from El Nino would be modest. The satellite data confirms this: we see temperatures rising steadily throughout the year but failing to exceed 2010 or 1998.
It is very likely that RSS/UAH will continue to rise sharply in the first few months of 2016. The million dollar question of course is: will 2016 exceed 1998 to become the hottest year in the satellite data series? The multi-million dollar question is: will El Nino 2015/16 'step up' global mean temperatures to a new level or will the inevitable follow-on La Nina be very deep and 'step down' global temperatures? For it should be obvious by now that ENSO is the vehicle whereby global warming/cooling is expressed - not the driver of warming/cooling, I hasten to add.
So anyway, logic tells us that, for 2015 at least, El Nino might only have contributed to a modest rise in GMST. Peter Stott of the Met Office says that El Nino contributed a "small amount on top", although it's not clear if this 'small amount' is to the 1C total rise since pre-industrial times or just to the spike in temperatures that the surface datasets show for 2015. I think most sceptics are interested in what the contribution might be just to the 'spurt' in global temperatures between 2014 and 2015, which, according to the Met Office, amounted to 0.18C. According to NOAA, the increase was a staggering 0.29C and NASA put the figure slightly less at 0.23C. Of course, we can rely upon that all-knowing Oracle of Global Warming, the Guardian to give us the lowdown on this vital question:
"A strong El Niño event is peaking at the moment, putting the “icing on the cake” of high global temperatures. El Niño is a natural cycle of warming in the Pacific Ocean which has a global impact on weather. But scientists are clear that the vast majority of the warming seen in 2015 was due to the emissions from human activity.
“Even without an El Niño, this would have been the warmest year on record,” said Prof Gavin Schmidt, director at Nasa’s Goddard Institute for Space Studies. He said he expected the long trend of rising global temperatures to continue because its principal cause – fossil fuel burning – was also continuing.
“It is clear that human influence is driving our climate into uncharted territory,” said Prof Phil Jones, from the University of East Anglia’s Climatic Research Unit, which produces the temperature record – called HadCRUT4 – with the Met Office."
I agree. Even without El Nino, 2015 would probably have been a record breaking year in the surface datasets. What I am more sceptical about is whether this contribution to record breaking warmth has come from man-made global warming or man-made temperature adjustments (courtesy of Karl et al for NASA/NOAA)!
Let us abandon the flights of fancy of the Guardian and Gavin and come back down to earth with the realisation that ENSO does contribute to global warming. the Met Office tells us that El Nino 1997/98 elevated global mean temperatures by 'at least 0.2C':
"The major El Niño of 1997/98 elevated the global mean surface temperature by at least 0.2C. Since then the increase in global mean surface temperatures has been small and this has been linked in part to decadal changes in the circulation of the Pacific Ocean".
What is important to note is that this was after the La Nina which followed. 0.2C was a measure of how much ENSO 'stepped up' global temperatures. This is very different from what sceptics and AGW convinced scientists are squabbling about on Twitter, i.e. the transient contribution to GMST from an El Nino happening now. In 2016 the transient contribution to GMST and LT temperatures may be very significant - much more than a few tenths of a degree perhaps - but the question is how will the global climate system setlle down after El Nino/La Nina? That is the really interesting question. Will we see a new 'high' established, from which point presumably global warming will take off again in earnest, or will we indeed witness global cooling in late 2016, on into 2017/18?

According to GWPF:

Nasa says that 2015 was 0.13°C+/-0.10°C above 2014. The UK Met Office said that 2015 was 0.18°C +/- 0.10°C above 2014. Noaa says 2015 was 0.16°C+/-0.09°C warmer than the previous record which was 2014.

Friday, 8 January 2016

Final Word on the 'Unprecedented' Rainfall of December 2015

So, it's official, December 2015 was the 'wettest ever' [smallprint: 'in the UK record going back to 1910']. Much fanfare at the Met Office, Guardian, Indie etc., blah, blah, blah. It beat 1929 to the top spot and 'though El Nino undoubtedly played a part, such events are predicted to become more common as climate change (TM) progresses because of simple physics' - the well worn statement of implicit attribution combined with appropriate caveat and unassailable 'scientific' logic is now very boringly familiar to most.
So, yes indeed it was the wettest December in the UK since 1910, but is there a trend? Hardly, looking at the graph above. Decembers were wetter in the early 20th century, then they got drier and from the 1970's they've got progressively wetter again - but not significantly wetter than they were in 1910 (one record does not a significant rising trend make). If we look at each country of the UK, we see in fact that England has in fact become drier in Dec since 1910:
Whereas Scotland shows the only really significant increase in precipitation in December:
The EWP record which goes back to 1766 and which has not been referenced by the Met Office and alarmist press as far as I know, shows that December 2015 wasn't even a contender for a top spot, exceeded in the record by numerous other years and coming nowhere near the record set in 1876.
ts_ewp_decemberThus we must conclude that, for whatever reason, the ravages of climate change have not been visited upon the Sassenachs!
But I hear them say in climate alarmist land: "Ah yes, but the rainfall intensity in the north and Scotland was unprecedented!" followed by, "We expect this due to climate change and simple physics" . . . blah, blah, blah, etc. etc. etc. Well, OK, yes, it seems that records were set at individual weather stations and the biggie was at Honister Pass - 341.4mm of rain in a 24 hour period (a new UK record). But all may not be as it seems. You see, a 'day' of rainfall has traditionally been measured from 0900 GMT to 0900 GMT. I quote:
"The 09-09 GMT record is important because from a historical context much of the data is daily data recorded over the standard 09-09GMT period."
So even though Dec 2015 set a record for most intense rainfall in any 24 hour period (a relatively recent method of measuring rainfall), it failed to set any records for a traditional rainfall day. The records still stand as follows:

Highest 24-hour rainfall totals for a rainfall day (0900-0900 GMT)

CountryRainfall (mm)DateLocation
England27918 July 1955Martinstown (Dorset)
Scotland23817 January 1974Sloy Main Adit (Argyll & Bute)
Wales21111 November 1929Lluest Wen Reservoir (Mid Glamorgan)
Northern Ireland15931 October 1968Tollymore Forest (County Down)
All of them, you will note, set 1974 or earlier, gong back to 1929. 2015 did manage to set the record for rainfall in a traditional 2 day period though, which now stands at 405.0 mm measured at Thirlmere, Cumbria. This was the only recognised traditional short period rainfall record set in December 2015. If we look at periods shorter than 24 hours, Dec 2015 doesn't even get a look in.

UK rainfall records for short durations

MinutesRainfall (mm)DateLocation
Highest 5-minute total32*10 August 1893Preston (Lancashire)
Highest 30-minute total8026 June 1953Eskdalemuir (Dumfries & Galloway)
Highest 60-minute total9212 July 1901Maidenhead (Berkshire)
Highest 90-minute total1178 August 1967Dunsop Valley (Lancashire)
Highest 120-minute total193#19 May 1989Walshaw Dean Lodge (West Yorkshire)
Highest 120-minute total155#11 June 1956Hewenden Reservoir (West Yorkshire)
Highest 155-minute total16914 August 1975Hampstead (Greater London)
Highest 180-minute total1787 October 1960Horncastle (Lincolnshire)
* Approximate value.
# Reservations about Walshaw value, Hewenden value is next highest accepted value.
So much for the expected increase in intense rainfall. You will note that most of the shorter period records are set in summer, as one would expect with strong convective heating. But even so, the most recent year in which an intense short period rainfall record was set is 1989. The rest go way back as early as 1893. 
So overall, we're not seeing evidence of December being particularly exceptional in terms of monthly totals or shorter period more intense downpours. Not exactly what the alarmists want the world to hear.

Monday, 4 January 2016

Betting on 2016

Mark Boslough recently issued a 'challenge' to 'deniers' to bet against him that 2016 would not be a record breaking year in the GISS dataset, hotter even than 2015, the current 'hottest year ever'. He seems to think that this single event will confirm that "global warming is real". Strange man. Anyway, with a very strong El Nino (now peaked), it is virtually certain that global temperatures will peak (naturally) in 2016. Furthermore, with the GISS incorporating NOAA's 'pause-busting' SST data, it is highly unlikely that 2016 will not turn out to be another 'hottest year ever'. So no sceptic worth their salt is going to take that sucker bet.
A more interesting bet would be whether 2016 will exceed the warmth of the current warmest year (1998) in the RSS and UAH satellite datasets. RSS data for December 2015 is in; anomaly is 0.54, up from 0.43 last month.
RSS Lower Troposphere Global Temperature Anomalies
Mark Boslough wasn't interested in taking up my offer of betting on this far less certain occurrence - surprise, surprise.
My personal opinion is that it's entirely possible that 2016 will not turn out to be the warmest year in the satellite data. Even though, in terms of Nino 3.4 SSTs, the 2015 El Nino was more powerful than 1997, Nino 1+2 regions lagged quite a bit behind.
In this respect, the 2015 El Nino, for my money, resembled more a Central Pacific (Modoki) type El Nino than it did the 1997 very powerful canonical El Nino. Note also that Nino 3.4 in 2015 started nearly 1 degree higher than 1997, courtesy of the strong Pacific warming in 2014. The Met Office has a very interesting analysis of El Nino events, in which they say:
"The major El Niño of 1997/98 elevated the global mean surface temperature by at least 0.2C. Since then the increase in global mean surface temperatures has been small and this has been linked in part to decadal changes in the circulation of the Pacific Ocean. It has also been noted recently that CP El Niño events do not have the same impact on global mean surface temperatures as EP El Niño events; global mean surface temperatures are, typically, anomalously warm during and after EP events, but not in CP or mixed CP/EP events. It is also the case that since 1998, El Niño has been dominated by CP events, and this recent paper suggests that since the late 19th century, periods of slowdown in the rate of global mean surface warming typically contain only CP El Niño events, and no EP events".
It would not surprise me therefore if 2016 fails to exceed 1998 as the warmest year recorded in the satellite data series. What of 2016 and beyond? There are three possibilities: the expected spike in global temperatures may initiate a 'step up' (like 1998 did), it may not affect global temperatures significantly, in which case the current Pause will continue, or it may initiate a 'step down' in global temperature via a very deep subsequent La Nina cooling. If we're betting, my money is on the latter in late 2016/early 2017. If we get another 'step up' in global LT temperatures, I will be the first to admit that the anthropogenic CO2 warming theory may have something going for it, because many current climate indicators (AMO/AMOC/solar) point to imminent cooling.

Update: 05/1/2016
Bob Tisdale has posted an updated graphic to the one above:
We can see that El Nino has clearly peaked in all regions. Nino 1+2 regions peaked considerably lower and several weeks earlier in 2015 than they did in 1997 and they are now declining quite rapidly. We shall soon see if this affects any resultant spike in global temperatures in 2016.