More Met Office Propaganda

By Paul Homewood

 

http://www.dailymail.co.uk/sciencetech/article-2217286/Global-warming-stopped-16-years-ago-reveals-Met-Office-report-quietly-released–chart-prove-it.html

 

I complained yesterday that the UK Met Office were misleading the public by not showing the full CET series on their website. This followed a similar complaint by Benny Peiser, of the Global Warming Policy Foundation, about the hushed release of the latest HADCRUT data showing that global warming stopped 16 years ago. Dr Peiser had this to say.

“It is quite scandalous that the Met Office is misleading the public. The latest data proves beyond any doubt that there has been no warming [trend] over the past 16 years.”

The story was well covered in the British Press and I don’t want to revisit it. However, I will say that the whole episode puts the MSM in an extremely unfavourable light. Rather than accusing the Met of a cover up, they might like to ask themselves why they have not found this information for themselves. The data is, after all, easily accessible, as is the data from the other main global datasets. Journalists should have been doing exactly what many of us have over the last few years – checking the facts for themselves and asking awkward questions of the Met and the others, instead of just cutting and pasting press handouts.

It seems, though, that the Met have dug themselves deeper into the hole in their reaction to the original article in the Daily Mail. Clearly irritated at the criticism, they released their own press bulletin, which attempted to deny the main thrust of the Mail’s article that global warming had stopped. Let’s take their reply point by point. (Their replies are in response to questions originally raised by David Rose, who wrote the article).

 

Q.1 “First, please confirm that they do indeed reveal no warming trend since 1997.”

The linear trend from August 1997 (in the middle of an exceptionally strong El Nino) to August 2012 (coming at the tail end of a double-dip La Nina) is about 0.03°C/decade, amounting to a temperature increase of 0.05°C over that period, but equally we could calculate the linear trend from 1999, during the subsequent La Nina, and show a more substantial warming.

As we’ve stressed before, choosing a starting or end point on short-term scales can be very misleading. Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system. If you use a longer period from HadCRUT4 the trend looks very different. For example, 1979 to 2011 shows 0.16°C/decade (or 0.15°C/decade in the NCDC dataset, 0.16°C/decade in GISS). Looking at successive decades over this period, each decade was warmer than the previous – so the 1990s were warmer than the 1980s, and the 2000s were warmer than both. Eight of the top ten warmest years have occurred in the last decade.

Over the last 140 years global surface temperatures have risen by about 0.8ºC. However, within this record there have been several periods lasting a decade or more during which temperatures have risen very slowly or cooled. The current period of reduced warming is not unprecedented and 15 year long periods are not unusual.

There are several misleading statements here:-

1) It is simply not true to say that August 1997 was “in the middle of an exceptionally strong El Nino”. The El Nino had only just begun at that time, and it is generally accepted that there is a time lag before global temperatures respond. This is abundantly clear in Figure 2, which shows that it was early in 1998 that temperatures peaked.

2) It is also not true that August 2012 is “at the tail end of a double-dip La Nina”. The La Nina, in reality, fizzled out in January 2012, and since April there has been a mild El Nino.

3) While they are quite right in saying that selection of start and end points is critical, it is nonsensical to compare the the 1999 La Nina with this year, as they suggest. A much more meaningful comparison would have been between 1999 and early 2012, when both temperature and the MEI (ENSO Index) were at similar levels.(See Figures 1 & 2).

 

Figure 1

 

Figure 2

4) I frankly find it astonishing that the Met, having warned about the dangers of cherry picking, then proceed to say “For example, 1979 to 2011 shows 0.16°C/decade “. As Figure 3 makes clear, 1979 was at at the end of a much colder decade. I wonder why they did not suggest using 1941 as a starting point? Or 1981?

 

Figure 3

 

5) They go on to repeat the usual mantra about the 2000’s being the warmest decade. This, of course, ignores the issue as to whether the trend is still upwards or not.

 

So let’s move on to Question 2.

Q.2 “Second, tell me what this says about the models used by the IPCC and others which have predicted a rise of 0.2 degrees celsius per decade for the 21st century. I accept that there will always be periods when a rising gradient may be interrupted. But this flat period has now gone on for about the same time as the 1980 – 1996 warming.”

The models exhibit large variations in the rate of warming from year to year and over a decade, owing to climate variations such as ENSO, the Atlantic Multi-Decadal Oscillation and Pacific Decadal Oscillation. So in that sense, such a period is not unexpected. It is not uncommon in the simulations for these periods to last up to 15 years, but longer periods are unlikely.

 

Again, this is a highly misleading statement, which fails to answer the question posed.

1) They are perfectly correct in pointing out the long term effects of ENSO, AMO and PDO. In which case, why did they also not point out the contributions these factors have had on the warming from 1980-96? They seem to be arguing that natural factors have led to the flat period, but were not a factor in the previous two decades.

2) They do not mention that the PDO was in a warm phase throughout the time when temperatures were rising, and has only recently gone negative. (See Figure 4)

 

Figure 4

 

3) They also do not mention that the AMO went positive in the 1990’s and remains so.

 

Figure 5

4) They do not mention that when both PDO and AMO were negative in the 1960’s and 1970’s, global temperatures plummeted.

5) They do not answer the question as to what this flat period says about IPCC models, which have tended to project forward the 1980-1998 warming trend.

 

And Question 3? Well, finally, they start to be a bit more honest.

Q.3 “Finally, do these data suggest that factors other than CO2 – such as multi-decadal oceanic cycles – may exert a greater influence on climate than previously realised?”

We have limited observations on multi-decadal oceanic cycles but we have known for some time that they may act to slow down or accelerate the observed warming trend. In addition, we also know that changes in the surface temperature occur not just due to internal variability, but are also influenced by “external forcings”, such as changes in solar activity, volcanic eruptions or aerosol emissions. Combined, several of these factors could account for some or all of the reduced warming trend seen over the last decade – but this is an area of ongoing research.

 

I suppose it’s nice to see them admit that there is an awful lot of things they do not understand about climate. However, again they fail to acknowledge that factors other than CO2 could equally have contributed to the warming in the 1980’s and 90’s.

It is also interesting to see them mention volcanoes. Without the eruption of Pinatubo in 1991, and its effect on temperatures over the next couple of years, we could be looking at no significant warming for 20 years. As they have already said “It is not uncommon in the simulations for these periods to last up to 15 years, but longer periods are unlikely. “

 

In attempting to deflect criticism, the Met Office have simply show how desperate they are to defend their agenda.

Don’t we deserve better of our publically paid servants?