Cool Dublin

Last year I posted an entry calling attention to the weak evidence of an upward trend in the temperature data for Dublin. As we learned from the debates about climate data before the Copenhagen Climate Change Conference, it is important for scientists to explore data that do not neatly fit their models. So I thought it would be worth adding another year to the material I posted last year. All but the most recent data are taken from the CSO database. For recent months I have used the Met Éireann data.

In 2009 the average temperature recorded at Dublin Airport was 9.5 degrees C, the same as that reported for 1958, the first year in the CSO’s database. The average for the thirty-year period 1961-1990 – used by Met Éireann to represent the long-run – was 9.6 degrees C.  The year 2009 was the second in a row when the average temperature was at or below the long run average.

There was no very warm weather in Dublin during the last two years. The highest temperatures recorded in both years were in June – only 22.3 degrees in 2008 and a somewhat better 24.8 in 2009.  Back in August 1990 a torrid 28.7 was recorded.

The warmest month in both 2008 and 2009 was August, with the same average temperature of 15.3 in both years. These values are low compared with July 1989, the warmest month since 1958, when the average was 17.9 degrees.

Last winter (December 2008, January and February 2009) was cold in Dublin, with an average temperature of 4.6 compared to the long-run average of 5.9. As we are well aware, December 2009 was very cold, with an average of 3.9, but the month was not as exceptionally cold in Dublin as in other parts of Ireland. A lower monthly temperature (3.7) was recorded in Dublin as recently as February 1996. However, record lows were recorded around Christmas and the New Year and into January 2010, so if things don’t warm up soon this winter (December 2009, January and February 2010) is set to break the record lows for Dublin too.

In December 2009 many newspapers carried headlines to the effect that the first decade of the twenty-first century was the warmest on record in many countries. Not so in Dublin, where the 1990s were fractionally warmer than 2000s. However, the variation between decades is very small – the standard deviation for the averages of the five decades since 1960 is only 0.21 degrees, compared with 0.42 for the fifty years of this period. The 1960s were relatively cold – average temperature of 9.4 – but since then the decade averages have only varied between 9.7 in the 1970s and 10.0 in the 1990s. The relatively low temperatures recorded in the 1960s prompted a lot of discussion of global cooling.

As shown in my previous post, the evidence of an upward trend in Dublin’s temperature is weak. The graph below shows the annual averages over the 52-year period 1958-2009. As noted above, the series actually ends up in 2009 where it starts in 1958, at 9.5. In most statistical analyses it would be hard to maintain the existence of a significant trend if over fifty years the series reverted back to where it started from!

In fact, for the whole 52-year period there is weak evidence of a statistically significant positive trend:

TEMP = 0.0097 (YEAR-1958) + 9.5163 R² = 0.1189

However, the relationship is unstable between sample sub-periods. This is illustrated simply by splitting the 52-year period into two halves. The result for the first sub-period (1958-1983) is

TEMP = 0.0144 (YEAR – 1958) + 9.4553 R² = 0.0796

The result for the second sub=period (1984-2009) is:

TEMP = 0.0062 (YEAR-1958) + 9.8118 R² = 0.0121

which is not significant at any of the usual levels.

There seems to have been a shift in emphasis from temperature to rainfall statistics in commentaries on Irish weather patterns. This is natural given the wet summers of 2008 and 2009 and the flooding during last November. But the rainfall at Dublin Airport last year was only 25% above the long-run average and well below the levels recorded in 2002, 1966, 1960, and 1958. There has been no significant trend in yearlt rainfall over the past fifty-two years.

Observations for fifty two years at one weather station may not have much significance for global weather/climate trends, but the lack of evidence for warming in Dublin surely merits more attention than it receives in Irish discussions of climate change.

77 replies on “Cool Dublin”

@BW

Does the data from 2009 alter your analysis of the data from 1958 to date as set out in your previous post?

I’ll start the comments thread by saying that global warming does not necessarily mean warming in all parts of the world. We could easily have cooling in localised areas that would fit in the overall GW picture. So local data taken out of the global context may not mean much.

“but the lack of evidence for warming in Dublin surely merits more attention than it receives in Irish discussions of climate change”

umm ya. It’s ~Global Warming~ not the local weather around the the Northside of Dublin.

The area of the island of ireland is 84,421 km2

The area of the siberian federal district is 5,114,800 km2

Googling John Sweeny of Maynooth will lead you to this paper:

Downscaling Climate Models for Ireland: Providing Future Climate Scenarios.

at http://www.ria.ie/committees/pdfs/hydrology/Sweeney.pdf

Sweeney’s is addressing Garo’s comment. Certainly taking a single point on the earth’s surface and using its temperature records as “evidence” or even as a rough indicator is probably not even as good as asking a man on the Donnybrook bus who he is voting for in the next election, and expecting that to be a reliable estimate. It is dangerous to generalise from the micro-climate of Dublin.

Eyeballing the chart, which I am led to do by my human nature, there seems a slight rise in average temp over the period in question. Sweeney is projecting about a 0.5 to 1 degree rise by the 2020s so this does not refute that.

A few years ago, there were fears that melting ice caps would re-route the North Atlantic Drift away from Ireland, rendering our winters more Scandanavian (just like this one, in fact!). Not sure what has happened to that theory. Sweeney certainly does not take it into account.

@ Brendan

What Garo said.

I wouldn’t think the evidence from one weather station deserves too much attention within the context of global warming debate, given that temperature trends are plotted using date from thousands of weather stations globally. In fact this data can and has been used fairly unconvincing and ill-informed manner to suggest that global warming is not occurring http://www.iiea.com/events/dr-conor-skehan-on-dublin-at-the-crossroads!! (see 12 mins) to ruin what would otherwise have been an otherwise excellent though highly patronizing presentation).

The data might be of more interest to Ireland’s scientific community in making localized climate projections.

On a sort of related aside, interesting article from today’s UK Indo makes the following observations:

Currently Northern Europe and Russia are experiencing temperatures that are below average. In Russia temperature is 10 degrees below 1960-1990 average from this time of year. However Southern Europe, North Africa, South West Asia and parts of the states and Canada temperatures are far above normal. In Canada up to +10 degrees.

Jeez, things don’t change. I remember people misinterpreting the original post last year as well.

@ Garo & Excel95
If you read carefully, you’ll note that Prof Walsh is not trying to prove/disprove global warming. He is investigating the effects (thus far) of global warming on Ireland. Using local measurements, it doesn’t look like global warming has effected us much directly.

This is, as he points out, worth taking into account when we are deciding how much we want to spend on climate policy. It’s not that we shouldn’t care if it isn’t affecting us much yet, but rather that it’s reasonable to break down our concerns into two (or more) components – concern for ourselves and concern for others. In terms of concern for ourselves, this evidence suggests that we’re not in trouble yet.

Why oh why oh why is everyone talking about the weather today? – especially on this blog. What’s the economic impact of everyone bunking off early in Dublin this afternoon because of half an inch of snow and not spending their money in small businesses on the brink that are struggling to survive? If the cold snap continues, will unemployment rise or fall? If councils have to spend their remaining budget on salt and grit, will business rates go up and make us less competitive?

Of course, I only left Dublin early today because I had to be in at some ungodly hour for a meeting this morning. Nothing to do with how cool it is!

@ Marcus OC

I agree but there is a very thin line. The chart has been used to suggest that global warming is not occurring (see the link above).

Would Professor Walsh care to share his views on global warming and put this misunderstanding to rest?

@ jc
I see where you’re coming from, but Prof Walsh isn’t responsible for other people’s use of similar charts (I watched some of the video in the link above, no mention of him).

In any case – see this comment by Prof Walsh from March last year on this topic.

Quote from Prof Walsh from March last year:

“I am puzzled as to why the evidence for Dublin over the past 51 years is less than striking.”

Why should you expect a geographical point on the east coast of a moderately sized island in a temperate zone to show anything other than “less than striking” effects of climate change? Besides, as we pointed out, any effect of global warming could easily be swamped in the short term by local micro-climatic factors.

Climaet, like macro-economics, is a large-scale aggregate phenomenon and it is surprising to find economists who do not understand that.

If you wanted to go to a place where there are striking effects you should look at the places of extreme heat or cold – the equator or polar ice caps, or high mountain glaciers.

@ toby

Is it so unreasonable to be surprised that there’s no statistically significant change in mean temperatures in Dublin? If one makes the assumption that global and local temperatures ought to be positively correlated in the long term, it is peculiar that Dublin temperatures haven’t risen much. Obviously there’s an explanation, but paying subtle insults and making vague claims about short term micro-climatic factors is unhelpful.

Oh and macroeconomics is not really a phenomenon. Incidentally, you may have noticed that recent macroeconomic phenomena have indeed been measurable in Dublin.

Marcus, in the previous post and comment in March, Brendan Walsh stated that he was puzzled as to why there wasn’t much evidence of GW in Irish climate data. My comment was simply a response to that.

One possibility, although not a certainty, is that it is just a random effect?

Met Eireann gives temperature data for 12 weather stations.

They all show varying changes for 2009 compared with 1961-1990.

At one extreme is Dublin Airport, which is the only one of the 12 to show a decrease (of 0.1 degrees) in 2009 over 1961-1990. At the other extreme is Birr, which shows an increase of 1.2 degrees in 2009 over 1961-1990.
The figures for the full set of 12, ranked in ascending order of change are as follows:

Dublin Airport – 1961-1990 average: 9.6 , 2009: 9.5 , change: -0.1
Cork Airport – 1961-1990 average: 9.5 , 2009: 9.5 , change: 0.0
Oak Park – 1961-1990 average: 9.4 , 2009: 9.7 , change: +0.3
Johnstown – 1961-1990 average: 9.6 , 2009: 10.0 , change: +0.4
Casement Airport – 1961-1990 average: 9.2 , 2009: 9.6 , change: +0.4
Shannon Airport – 1961-1990 average: 10.1 , 2009: 10.6 , change: +0.5
Valentia – 1961-1990 average: 10.4 , 2009: 11.0 , change: +0.6
Claremorris – 1961-1990 average: 8.9 , 2009: 9.5 , change: +0.6
Malin Head – 1961-1990 average: 9.3 , 2009: 10.1 , change: +0.8
Belmullet – 1961-1990 average: 9.6 , 2009: 10.5 , change: +0.9
Mullingar – 1961-1990 average: 8.8 , 2009: 9.7 , change: +0.9
Birr – 1961-1990 average: 9.3 , 2009: 10.5 , change: +1.2

The average for the 12 weather stations is an increase of just over 0.5 degrees. As far as I know, this is roughly similar to the increase in global temperatures in the same period. But, if that is the average for the 12 weather stations, then the laws of chance would suggest that some be a bit above this figure and others be a bit below. That is one possibility.

However, there might be significance in the fact that all the airport weather stations showed below-average increases. These are also the weather stations that are located in the large cities. Maybe Professor Walsh has hit on something there? If we are talking about Dublin in particular, I’m not from near Dublin, but isn’t Casement Airport also in Dublin? So, maybe, for Dublin we should average the Dublin Airport and Casement Airport figures? That would still leave the Dublin increase well below the average increase for the country as a whole, as would Cork’s.

I keep an open mind on the global warming debate, neither an alarmist nor a denier. But, as I understand it, both sides agree that the earth has warmed by about 0.5 degrees since the 1960s, which appears to be roughly similar to what Ireland has experienced. That warming is not disputed. The two sides differ only in relation to (a) the cause of the warming (carbon emissions v sun spot activity) and (b) whether the warming stopped around 1998.

As my family have a holiday house near Malin Head, its very nice to know that in 2009 Malin Head was warmer than Dublin or Cork. It must be the winds blowing in from the North Pole that’s causing it.

I thought one of the (admittedly modelled) effects of global warming would be to push the Gulf Stream lower, thereby creating a new, colder climate for Ireland and Britain, akin to those on their Easterly latitude such as Germany?

If this is not a climate change counter-thrust, and this is an investigation into how much should be spent on Green energies, shouldn’t we begin with benefit analysis of various forms of energy production and their like long-run costs?

Why begin energy policy with a discussion of the weather?

@Mark Yup as I understand if with a lot of ice melting from the Arctic & flowing south, it could basically knock out the Gulf Stream and then we could have the same climate as Montreal. Hopefully we would not end up speaking with the same funny accent but many of our buildings would not cope with that climate.

Prof. Walsh, as MarcusOC rightly points out, is merely trying to show that climate change’s effects on Ireland have been few, and that we should take lessons from that in terms of public policy. I think there are three problems with this analysis, even setting aside the international problems Ireland would face if the rest of the world experienced warming without us.

1. Average temperatures can disguise weather extremes. Very hot summers and very cool winters could well have the same annual average temperature as a year of moderation, as the two extremes offset each other. I don’t know whether this is the case in Ireland, but it’s not hugely relevant, because of the next two points.

2. The most harmful effects of climate change don’t run on a straight or smooth curve. The effects of climate change aren’t part of a gradual process. They aren’t even part of a accelerating process. For example, one could record no change whatsoever in Irish temperatures, yet temperature changes elsewhere (causing, for example, the Gulf Stream to shut down) would have a significant and fairly instant effect on Irish climate. Previous examples of warming, cooling, or no change in one area are in no way evidence of future patterns, especially when you take into account significant climatic events.

3. Dublin isn’t Ireland. I remember someone pointing out before that Ireland’s overall warming is fairly consistent with international norms, but I’d have to look that up.

MarcusOC asked

“Is it so unreasonable to be surprised that there’s no statistically significant change in mean temperatures in Dublin?”

Well, what is the expectation or prediction of climate scientists? It is someting like 0.5C-1C mean change worldwide since the 1970s. That worldwide mean is made up of numbers greater and less. Ireland, being temperate, would not contribute much change – say less than 0.5C if any. That is not really large enough for such a shift to be spotted in a temperate zone over the time scale. Sweeney (see my post above) is not predicting such a shift in Ireland until after 2020.

So, the slight increase that seems to be seen at Dublin Airport by eyeballing the data is probably not large enough to be statistically significant. That fact does not refute that climate change is happening, and that Ireland will be affected. I submit that it is unreasonalbe (certainly unscientific) to be surprised by that.

JohnTheOptimist

For the 12 changes in average, the mean of the averages is 0.54C (close to lower end of the climate scientists prediction!). However, the standard deviation is 0.38. Since the mean – 2(standard deviation) = -0.21 <0. Therefore, the change is statistically indistinguishable from 0, so it IS a random effect.

To that extent you are right, however few if any conclusions can be drawn from a random effect. For example, if the effect as a whole is random then there can hardly be a “Dublin effect” as you think. Dublin average increase is 0.15C, for the rest it is 0.62 – you can see that the Dublin figure is not far off the mean, the sdev about equal (0.35).

More complex models could probably be built with the raw data – I would recommend the CRU of the University of East Anglia :), but I do not think they would find anything different to my crude analysis.

Let me add that the existence of an “urban effect” or an “airport effect” in weather data (also a “satellite effect” for space data) has long been refuted as contrary evidence to climate change. Also the jury has been in for a while on sun spots – while they have an effect, but their natural forcing is dwarfed by CO2.

Also, some of the warmest years since records began have come since 1998, so the canard that “global warming stopped in 1998” is gone with the wind as well. See

http://climate.nasa.gov/keyIndicators/

” The year 2008 was tenth warmest on record, exceeded by 1998, 2005, 2003, 2002, 2004, 2006, 2001, 2007 and 1997″

While I am on the topic …

It would be totally unreasonable to do what has been suggested and base our public policy on existing weather data. Is this not to fall into the fallacy that the future is going to be identical to the past?

It would be like predicting the temperatures of the last month from the temperatures in October or mid-November.

What the science is saying is that we are at the start of a cycle of average temperature increase with significant ramifications – increased rainfall & flooding in winter, water shortage in summer, rising sea levels, increased winter storms etc. Public policies must adjust to these in timely fashion on a principle of simple prudence.

It does make sense to take the climate change models and validate them from an Irish perspective. Then taylor the models accordingly. That is what Prof Sweeney is trying to do in this paper:

http://www.ria.ie/committees/pdfs/hydrology/Sweeney.pdf

To stovepipe onto Irish data only (from a relatively tiny geographical area), and try to interpret it independently of data from other points of the earth’s surface would be a grave mistake.

@ toby

Fair points. However you said:

“That fact does not refute that climate change is happening, and that Ireland will be affected. I submit that it is unreasonalbe (certainly unscientific) to be surprised by that.”

Nobody here even suggested that this disproved climate change. Similarly, nobody really suggested that Ireland wouldn’t be affected (in the future).

@Marcus OC

Let me put it this way:

“So, the slight increase that seems to be seen at Dublin Airport by eyeballing the data is probably not large enough to be statistically significant. I submit that it is unreasonable (certainly unscientific) to be surprised by that.”

@toby

I might not have expressed myself clearly, but I wasn’t saying that the average figure for Ireland as a whole (+0.54 degree increase) was a random effect. I was saying that, within the Irish dataset of 12 weather stations, the fact that some were above the average for Ireland and some were below the average for Ireland might well be random. Obviously, the average figure for Ireland as a whole is more reliable than the figures for individual weather stations, in the same way that the average of 12 opinion polls is more reliable than any particular one of the 12 considered in isolation. Neither was I arguing in favour of (or indeed against) the sunspots theory or the view that global warming stopped in 1998. I was merely listing very briefly the points of difference between the two sides, while pointing out that both sides agreed that global temperatures have increased since the 1960s (while differing on the reasons).

@Marcus OC

If nobody is suggesting that this disproves anthropogenic climate change, and nobody is suggesting that Ireland won’t be affected – just what is this article suggesting?

“Observations for fifty two years at one weather station may not have much significance for global weather/climate trends”

exactly, so what is the point of this article ?

@Pidge
Just take it at face value. There is no hidden agenda.

Dublin Airport has not warmed over the last 50 years.

That does not mean that other places have not warmed or cooled, or that Dublin did not warm or cool before 1958, or that it will not warm or cool after 2009. It just means that Dublin Airport did not warm or cool over the last 50 years.

“Having worked for several years with computer models of complex flow and heat transfer systems, which were validated against experimental data, I suggest that there is no validity for the results of any computer models of the climate. With so little understanding of how the climate works (the effect of the sun, ocean currents, the atmospheric layers and constituent gases etc), it is evident to any scientist that, with so many degrees of freedom and unknown parameters, the computer models can produce any outcome desired. If we cannot reliably calculate the weather more than a few days in advance, how is it that the IPCC can make forecasts for the climate 100 years ahead?”

http://www.parliament.the-stationery-office.co.uk/pa/ld200708/ldselect/ldeconaf/195/195we07.htm

Global Warming Ate My Data

“The world’s source for global temperature record admits it’s lost or destroyed all the original data that would allow a third party to construct a global temperature record. The destruction (or loss) of the data comes at a convenient time for the Climatic Research Unit (CRU) in East Anglia – permitting it to snub FoIA requests to see the data.”

“Even if WMO agrees, I will still not pass on the data. We have 25 or so years invested in the work. Why should I make the data available to you, when your aim is to try and find something wrong with it.”

That’s Phil Jones.

Apparently he doesn’t like scientific enquiry.

http://www.theregister.co.uk/2009/08/13/cru_missing/

Anthropogenic Global Warming is a lie.

Has anyone got evidence that it is not a lie?

“And the whole apparatus for spreading knowledge – the schools and the press, radio and motion picture – will be used exclusively to spread those views which, whether true or false, will strengthen the belief in the rightness of the decisions taken by the authority; and all information that might cause doubt or hesitation will be withheld. The probable effect on the people’s loyalty to the system becomes the only criterion for deciding whether a particular piece of information is to be published or suppressed.” –Friedrich A. Hayek, The Road to Serfdom, 1942 (Chapter XI – The End of Truth)

Anthropogenic Global Warming is a lie.

Has anyone got evidence that it is not a lie?

“Not only is the Kyoto approach to global warming wrong-headed, the climate change establishment’s suppression of dissent and criticism is little short of a scandal. The IPCC should be shut down… In Europe, where climate change absolutism is at its strongest, the quasi-religion of greenery in general and the climate change issue in particular have filled the vacuum of organised religion, with reasoned questioning of its mantras regarded as a form of blasphemy.” Nigel Lawson, former Chancellor of the Exchequer.

Anthropogenic Global Warming is a lie.

Has anyone got evidence that it is not a lie?

“Dinan’s Washington Times report said “Christopher C. Horner, a senior fellow at the Competitive Enterprise Institute, said NASA has refused for two years to provide information under the Freedom of Information Act that would show how the agency has shaped its climate data and explain why the agency has repeatedly had to correct its data dating as far back as the 1930s.””

http://www.manilatimes.net/index.php/component/content/article/86-special-reports/7311-nasa-penn-state-u-new-zealands-niwa-face-questions-as-panel-investigates-data-suppression-

Anthropogenic Global Warming is a lie.

Has anyone got evidence that it is not a lie?

@Greg

I don’t think we are going to defend the consensus of world climate science for everyone who pops up with a “when did you stop beating your wife” type of question, and who has nothing to contribute otherwise.

There are myriad texts, papers & blogs you can read so why not save us all your waste of space and go there?

Given some of the other responses, I can only conclude that Brendan Walsh was doing some random meditations on temperature data and pressed the “Submit” button accidentally. He did not mean to question anthropogenic global warming (check); he did not mean to say that global warming will not affect Ireland (check); he did not mean to say that we should decide our public policy according to temperature data from Dublin Airport (check).

@JohnTheOptimist

“I was merely listing very briefly the points of difference between the two sides, while pointing out that both sides agreed that global temperatures have increased since the 1960s (while differing on the reasons).”

“Two sides” implies a 50-50 split among climate scientists. It is more like 95% of climate scientists, who broadly accept the current models of anthropogenic CO2 forcing climate change, against a ragbag of assorted geologists, meteorologists, economists & cranks, mostly funded by the carbon generating energy corporations. What debate there once was is now over.

I love Climate Science.

All of that data suppression, destruction and manipulation.

Isn’t science just great?

How do I become the Pope of Climate Science?

Is there a job application form that I can fill in?

Do you believe in suppressing data?

Yes.

Do you believe in destroying data that doesn’t fit you political agenda?

Yes

Do you believe in manipulating data to keep your grants, salary and pension?

Yes.

Oh, I just became the Pope of Climate “Science”.

“I don’t think we are going to defend the consensus of world climate science for everyone who pops up with a “when did you stop beating your wife” type of question, and who has nothing to contribute otherwise.”

I’m not sure who the “we” are that you refer to.

I wasn’t aware that there was a “world climate science”. Is that different from science?

What do you have to contribute? And what are you contributing to?

“There are myriad texts, papers & blogs you can read so why not save us all your waste of space and go there?”

Where should I go toby?

Have you any EcoFascist site that will prove Anthropogenic Global Warming?

Just one toby. Just one.

“why not save us all your waste of space”

Now that is pure Fascism toby.

Should I kill myself because you disagree with me?

Or should I just wait for your Greenshirts to take me away to some “education camp” and dispose of the body later?

(check), (check), (check),

What is that toby?

Is that an EcoFascist making sure nobody gets out of line?

The thing is toby, Fascists disgust me.

Eco or otherwise.

Maybe you’re a happy Fascist.

Just stop beating your wife.

Greg,

If you understood properly how science works then you would not have posted any of your comments above. Your posts are denialist, pure and simple.

One of many websites available for debunking denialist nonsense is realclimate.org. I’m loathe to mention it as anyone can randomly start firing links around the place, anyone can Google ‘Global Warming Is A Lie’ and find thousands of links to back up your claim etc, but realclimate doesn’t pontificate, it deals in rational analysis.

Neither the two line statement that you repeated on the end of five of your posts nor your slightly unhinged response to Toby above do you any favours. And you possibly proved Godwin’s Law in the process. But at the end of the day it is all about the data and the analysis, and the data says that greenhouse gases emitted as a result of human activity are responsible for rising global temperatures.

Greg,

I want to post this, so you might see why your ‘Pope of Climate Science’ comment is complete nonsense.

Scientists form a hypothesis of the as-yet unkown, based on what is already known. The very first thing those scientists will do is try very hard to disprove that hypothesis. When they fail, they have a good reason for believing their hypothesis to be correct. It is now a theory. When that theory is published, other scientists will try very hard to disprove it. When they fail, the theory gains consensus.

Science only works by disproving and rejecting wrong ideas thus allowing correct ideas to flourish.

To persist with the conspiracy theory that the vast majority of the entire planet’s climate scientists are wrong, and know they’re wrong, about AGW is just plain daft.

@dealga

Thanks for ushering in some commonsense.

realclimaet.org is a good recommendation – the book that clinched the science behind global warming for me was “The Long Thaw” (Princeton, 2009) by David Archer, who blogs on the site.

Other sites are:

http://www.desmogblog.com/
http://climateprogress.org/
http://www.grist.org/
http://climateprogress.org/

Tim Lambert’s Deltoid blog contains many amusing demolitions of leading climate change deniers like Ian Plimer and Lord Monckton, who seem to be the latest “Gods” of the denialist movement. Plimer was on Pat Kenny, though I missed it.

http://scienceblogs.com/deltoid/?utm_source=bloglist&utm_medium=dropdown

But surely, “it is all settled science”!
WE don’t need no stinkin’ debate or facts, the UN has spoken.

It is clear to me that as absentee landlords we peasants have been guilty of allowing our servants to take charge and now they run the place! Time for a little cleaning of house! Fewer barriers between the ruled and the rulers!

Time for the emporer to buy a new suit in the January sales. His current one isn’t suitable for the current climate.

Thanks for all (well, most) of your comments. I think it is worth keeping this topic live on an economics Blog in view of the immense amount of money that is being and will be spent on reducing carbon emissions in the belief that this will avert or at least reduce some nasty economic impacts.

@zhou_enlai
Adding the extra year to the earlier dataset reinforces my earlier point about the weakness of the evidence of a trend.

@Garo
“I’ll start the comments thread by saying that global warming does not necessarily mean warming in all parts of the world. We could easily have cooling in localised areas that would fit in the overall GW picture. So local data taken out of the global context may not mean much.”
Many others echo this view. And there’s a letter in today’s Irish Times, for example, that asserts that “one cold spell does not serve to refute or even call into question the IPCC’s climate projections.” Science is all about refutable hypotheses. What evidence would actually refute the hypothesis of global warming or its softer “climate change” morph, which is the basis for spending billions, no trillions, of dollar/euros?

Many commentators dismiss as selective/irrelevant any evidence that runs counter to the dominant view of “global warming”. But episodes of extreme weather than tend to confirm the hypothesis are given uncritical attention and regarded as portents of worse to come. Remember continental Europe’s extremely hot summer in 2003? Remember Hurricane Katrina in 2005?

@excel95 and many others
Of course Dublin is a small and insignificant spot on the globe, but it happens to be where I and many of the readers of this Blog live, so evidence on what is happening here over the past 52 years is surely of some interest to us (and is not covered by our national press). Furthermore, what’s happening to ice melt in Siberia or the Arctic ultimately matters to us mainly through their effects on Dublin’s weather/climate. Sorry to be insular, but that’s life.

@Toby, Mark, Kevin Denny and others
Do we really understand the role of the Gulf Stream (or whatever it is now called) on the Irish climate? There is a risk that the model you mention will allow commentators to have it both ways – global warming implies Irish cooling. I urge you all to read what seems to me to be an erudite rebuttal of this model of the climate of the “British Isles” http://www.americanscientist.org/template/AssetDetail/assetid/51963?fulltext=true&print=yes.

@JohnTheOptimist
Thank you for adding some useful additional data. I agree that it would be worth taking data for both Casement and Dublin Airports together, but the CSO database does not include Casement.
You are right to draw attention to the fact that Dublin Airport seems to be somewhat of an outlier compared with other Irish weather stations in terms of the trend in average temperatures. I drew attention to this in my earlier post. But I also noted that the time series for some of the other stations (Shannon and Belmullet were the ones I picked) there is same break in the apparent trend that is evident for Dublin – while there may be a positive trend over the whole 52-year period, it weakens or disappears over the last 26 years.

Many of you mention models of climate change. It seems to me that their very complexity runs the risk that they will miss some crude “inconvenient truths” – much as more and more sophisticated financial risk models failed to see the wood for the trees over the last decade. Levitt and Dubner have a lively discussion of climate models in their Superfreakonomics (pp. 181 ff) that leaves me not knowing what to believe.

@Brendan Walsh

The role of the Gulf Stream is not fully understood. Like all sciences, climate science is not exact. The effects of global warming (melting of polar ice caps) on ocean currents is still under investigation. At the moment, the assumption being made is no Gulf Stream effect i.e. it will continue to mitigate our climate.

I take issue with your assertion to JohnTheOptimist that “Dublin Airport is an outlier”. If you read my response to John above you will see that the DA change of -0.1 is not far from the mean of 0.54 change, when the standard deviation of the data is 0.35. In fact, John’s data shows no significant change in Irish temperature, which does not refute any current predictions. This is hardly worthy of comment, and you & John seem to be trying to build a mountain out of a small molehill.

BTW, Leavitt & Dubner have been well shown at this point to be taking through their fundaments. Even the scientists they quoted have disowned them. See (as daelga suggested) realclimate.org or http://climateprogress.org/

The link to the American Scientist paper did not work for me.

@BW

Thanks for the responses.

“Adding the extra year to the earlier dataset reinforces my earlier point about the weakness of the evidence of a trend.”

I was suspicious that you posted the comment because we are in the middle of a cold snap!

I am surprised that one year makes such a difference to a trend over 50 years. Isn’t that why we were taught in inter-cert geography that climate is measured over 40 years and one was looking at weather, not climate, over shorter periods? Also, as I recall you previously found that there was a trend of increasing termperature over the last 50 years.

“What evidence would actually refute the hypothesis of global warming or its softer “climate change” morph, which is the basis for spending billions, no trillions, of dollar/euros?”
Presumable evidence obtained by taking measurements at a global rather than a local scale. Also, measuring climate sensitive data such as icecap melt, glacier melt, ocean PH levels, ocean flora and fauna, atmospheric composition, might also yield credible data.

“Many commentators dismiss as selective/irrelevant any evidence that runs counter to the dominant view of “global warming”. But episodes of extreme weather than tend to confirm the hypothesis are given uncritical attention and regarded as portents of worse to come.”

That’s true. If, however, the overwhelming evidence supports the hypothesis of climate change then I expect we shouldn’t get too upset by these spurious associations. Also, if climate change will cause more extreme weather then one can hardly expect people not to point to extreme weather as evidence of climate change rather than a possible symptom. “Evidence” for the lay man is not necessarily the same concept as empirical evidence for the professional academic.

[I was going to say two wrongs don’t make a right but I fear that would be to misrepresent the effect which you say 2009 has had on the model.]

“Furthermore, what’s happening to ice melt in Siberia or the Arctic ultimately matters to us mainly through their effects on Dublin’s weather/climate. “

I don’t think that premise stands up. I would have though the opposite, i.e. that the effect of climate change on the oceans, the global economy and political tensions and actions across the globe will be of more importance to Ireland than whether one can get away without wearing a nerdy vest in February. Furthermore, sea levels are hardly determined by the temperature in Ireland.

“Many of you mention models of climate change. It seems to me that their very complexity runs the risk that they will miss some crude “inconvenient truths” – much as more and more sophisticated financial risk models failed to see the wood for the trees over the last decade.”

The complexity of the models will possibly never sufficiently reflect the complexity of the global climate. However, I think focussing on Dublin is looking at a tree rather than the forest. The concept of tipping points for climate change (melting of polar ice-caps, melting of glaciers in asia, acidification of the ocean) cannot be accounted for in the type of analysis you have carried out.

“Sorry to be insular, but that’s life.”

This reminds me of John Bruton’s comment in his recent article in the IT that people don’t want to take responsibility for their actions. If one sees people starving because of desertification in Africa arising in part from reduced rain-fall arising from climate change then one may not connect it with one’s own actions. one might prefer to put all the blame on Kevin Myers’ tumescent gunmen.

I don’t think that is the preferred attitude of most Irish people. More importantly, we have joined the EU in part so we can be part of the effort to change the world for the better. Individuals can be insular but the Irish State as mandated by the Irish people has decided not to be so insular.

*BW

Thanks for the link to the Richard Seager article.

My own discipline is statistics (not in an academic or financial institution!) so my knowledge of climate science is informed only by my personal reading & whatever parts of my science education I can bring to bear.

Seager is arguing that “what we learned school”, that the Gulf Stream warms us in winter and cools us in summer, is false. Ireland is on the same latitiude as Labrador but the two different climates can be explained solely by other factors (he asserts). His culprit is actually the Rocky Mountains 🙂

If you look at his website, http://www.ldeo.columbia.edu/res/div/ocp/gs/ ,
you will find that Seager is within the climate science consensus on global warming/ climate change. This book (“Global Warming: A Very Short Introduction” (Oxford, 2004), Mark Maslin) gives a good overview of the effect of global warming on deep ocean circulation. Basically, Maslin brackets the Gulf Stream effects with the Siberian frozen methane and the monsoon. At the moment, scientists are just ensure of the effect global warming will have on those climatic factors. We really do not want to find out, but we may.

Quote from Seager’s site: “… we need serious assessments of how changes in ocean circulation will impact climate change and a new look at the problem of abrupt climate change that gives the tropical climate system and the atmosphere their due as the primary drivers of regional climates around the world. ”

The best approach in NOT to become frozen in indecision or denial. Cearly, CO2 emissions must be reduced in any event. Meanwhile, policy must evolve along with the science.

Brendan

Your piece, while it does not challenge the theory of AGW one way or another, is interesting in that it raises an important question: “If observed Climate Change continues to have no appreciable impact on Irish people environmental or otherwise, why should we adopt policies (taxation and grant/subsidy) that reduce our wealth today”;

Having studied the IPCC collated evidence for AGW, I believe the case that mankind is responsible is possible but along way from proven.
First of all, the ability to reconstruct world temperature stats for recent past 2000 years has always struck me as dubious and recent CRUgate emails have raised these concerns (and no there are not hundreds of peer-reviewed independent sources for re-constructed climate). Without confidence in the past, we really cannot rule out natural variations being the norm (even the IPCC admit 10% chance in recent report).

Secondly predicting future climate in 50 to 60 years based on computer models similar to that used for current weather forecasting – well I suppose if temp can only go down, stay the same or go up then they have 33% chance of being right ;-). If someone presented a computer program to predict stock prices 50 years from now based on their ability to predict past performance – I think most of us would also be dubious…..even if 20 different models predicted the same.

Having said all that many leading scientists argue that the proven thermodynamic properties of increasing CO2 (0.01% change in air composition since 1850 – yes it is that small) is having an impact – allowing for all the various feedbacks. So let’s say that one can reasonably sit on both sides of the AGW fence.

Whether AGW is a fact or not (Richard Tol would have a considered view that differs from mine), here are some reasons why we should not embark on a climate-change mission as being promoted by our current Minister for Environment

1. In general, a warm climate better supports life than colder climates.
Contrast diversity of life in tropics and temperate regions with barren polar regions (Hands up anyone who would prefer to live in Greenland rather than South of France). As evidenced by recent cold snap, let’s hope that we are still in a warming trend – far more serious for mankind if we were to revert to a cooling trend which in geological terms happened just a brief second ago (in last ice age).
3. On balance, for a northern located isle, a warmer climate would be beneficial to the population of Ireland. This is due to improved weather, lower energy costs, improved agriculture, less need to travel on foreign holidays etc.
4. Even with a temperature change, increased CO2 levels have a proven beneficial impact on plant growth and by extension food production – (yet SEI now measure how clean cars are by how much C02 they produce!). Why is this fact not emphasized – because it does not meet a certain agenda.
5. Even if the AGW theory is correct, our small population is irrelevant in terms of global climate impact. We are being punishing ourselves based on per capita CO2 production even though Ireland as a whole could have no impact on global climate.

In light of these facts, it is I argue very rational to question both the logic and policy of our government in this area. They are supposed to be representing the best interests of the Irish people but instead have chosen an ideological climate-change/climate justice (whatever that is) view that will if further developed force what is left of energy-based manufacturing to move off-shore and reduce our quality of life and economic well-being.

Jerome

Good to read your views, which I regard as very balanced. It is reassuring to know that the debate is still open.

@Brendan Walsh: One swallow does not the summer make. I am equally critical of those who cite a single hot summer or a single tropical storm as evidence that climate change is occurring. For me, (and I am not a climate scientist so I may be wrong here) a simple refutation of GW would be if the average temperature of the globe were shown to be not statistically significantly higher for a long enough period – a decade or two will suffice.

“Sorry to be insular but that’s life”

And therein lies to root of most of Ireland’s current economic troubles.

@brian
Thanks for the link to the Met Eireann piece. (I specially appreciated the photo at the end!)

What I take from this description of ongoing research is that progress is being made and that in the future it may be possible to obtain more reliable medium- and long-term forecasts. This contrasts somewhat with the general impression that the IPCC and others already have reliable forecasts for the coming 100 years, conditioned on varying levels of carbon emissions.

Moreover, a lot of the promise of increased future reliability seems to be based on very elaborate modelling initiatives that are a long way from completion.

“The IPCC plans to produce a new Assessment Report (AR5) in 2013/14 that will bring together the latest knowledge concerning climate change and future prospects for the Earth’s climate. Many international groups involved in climate modelling are currently in the process of running, or are planning to run, global climate models to provide basic information that will underpin AR5. The focal point for this work is the Coupled Model Intercomparison Project (CMIP), established under the World Climate Research Programme (WCRP). CMIP provides the experimental protocols for the simulations.”

“We cannot eliminate the uncertainty in the climate predictions but to some extent we can box it in by launching our model from slightly different initial conditions; the spread in the resulting ensemble of forecasts is a measure of the uncertainty. Concentrating on the next 10-30 years an ensemble of simulations will be carried out with EC-EARTH.”

Meanwhile, my eye was caught be the following passage:

“Is the recent (November 2009) spell of exceptionally wet weather part of a trend, a signal of climate change? We simply don’t know.”

@JeromeK

The book that converted me to the fact of global warming is “The Long Thaw” (Princeton, 2009) by Dave Archer, who blogs at realclimate.org.

(1) I don;t believe the fact of global warming can be doubted in the face of these indicators. http://climate.nasa.gov/keyIndicators/
The last IPCC report is already out of date (3 years old) & the evidence since is all confirmatory.
(2) Climate and economics may both be chaotic systems. However, economics has human agents which are inherently unpredictable in that the predictions can themselves influence behaviour. So 20 economic models agreeing might be ho-hum, but 20 climatic models driven by sound physics is a much more significant proposition.

Naturally, I respect honest doubt, but I still dissent from your do-nothing policy. Airily assuming that climate change will be “neutral” for Ireland is like the fallacy that we would be unaffected no matter who won World War II. No doubt you agee that Ireland should so all in her power to prevent (say) a US-China war because of the human and material devastation it would bring about. Same goes for an Israeli-Iranian nuclear war. Global warming would lead to at least as much economic and human misery, so we cannot be neutral but adopt a prudential policy & live up to our international obligations.

Irelands weather depends mainly on the position of the Jet Stream.
I have read eminent professers waxing elequent on Ireland,s future weather qualities, yet have never seen any reference to the Jet Stream.
This certainty about Ireland`s future weather would presuppose, that the mechanisim of the Jet Stream is well understood, this I believe is not the case.
Can anyone enlighten me further ?

How do they know that the global warming (such that it exists) is not part of the natural cycle? We are between ice ages and, on balance, I suspect warming would benefit the earth if the rate of change is not too fast.

If people are really so concerned about this issue and reducing their consumption and destroying any possibility of economic progress in the 3rd world, they should check out Superfreakonomics for a way that might just allow for man to moderate climate change, i.e. pumping sulphur into the atmosphere.

@BrendanWalsh,

The uncertainty in climate models is not an excuse for inaction. This is enshrined in the “Precautionary Principle”, which can be enunciated as follows (among other ways).

Suppose our prediction is an average over the planet’s surface of 3C warming plus or minus 5C – a range of -2 to +8. Argument for inaction? Well, the projection is an 8C average warming over the earth’s surface would render it unhabitable. Are we going to sit around and hope the warming is less than 3C?

We take out insurance on the assumption that the universe does not guarantee outcomes favourable to our fondest wishes.

So we have to consider the impact of inaccuracy & not just hope it is benign. You are always aware that chaotic systems can “bifurcate” and be irreversible.

The precautionary principle is better enunciated here:

http://www.samefacts.com/2009/12/climate-change/precaution-uncertainty-insurance-and-morality/

denis & Ciaran,

These are “Climaet Science 101” type questions so I can only suggest you consult some of blogs, websites & books mentioned above. http://www.realclimate.org is a good place to start.

One in particular has a good demolition of Leavitt and Dubner. Certainly, it made cross their book off my Christmas wish list, loved Freakonomics though.

http://climateprogress.org/2009/10/19/anatomy-of-a-debunking-yes-caldeira-says-superfreakonomics-is-damaging-to-me-because-it-is-an-inaccurate-portrayal-of-me-and-filled-with-many-statements-that-are-misleading-statements-a/

Economists making pronouncements about climate change is an interesting phenomenon – they completely understand the complex statistical tools being used by the climate scientists to draw conclusions, yet they have little or no education in the science of Earth’s climate itself.

Again, anyone who uses terms like ‘the science is settled’, ‘there is no room for debate’ etc simply has no clue how science works.

JeromeK said:
“1. In general, a warm climate better supports life than colder climates.
Contrast diversity of life in tropics and temperate regions with barren polar regions (Hands up anyone who would prefer to live in Greenland rather than South of France). As evidenced by recent cold snap, let’s hope that we are still in a warming trend – far more serious for mankind if we were to revert to a cooling trend which in geological terms happened just a brief second ago (in last ice age).
3. On balance, for a northern located isle, a warmer climate would be beneficial to the population of Ireland. This is due to improved weather, lower energy costs, improved agriculture, less need to travel on foreign holidays etc.”

It irritates me greatly when people suggest that climate change will lead to Ireland having weather more like the South of France. What evidence whatsoever is there that we will have nice dry mediterranean summers as a result of climate change? Then there is the suggestion that we will be like the tropics – that well known centre of agriculture and fertility. Egad! as the comic book characters say.

Postscript:

Here’s some reading suitable for the frigid weather we are having:

Arctic Ireland: The Extraordinary Story of the Great Frost and Forgotten Famine of 1740-41

by David Dickson Belfast: The White Row Press, 1997

David points out that there never has been a definite scientific explanation for the twenty-one months of bizarre European weather between December 1739 and September 1741. The cold spell that started at the end of 1739 seems to have been the worst ever experienced in Ireland. (There are no reliable temperature data for this time – but in England there were readings of 32 degrees of frost – that is -18 degrees C.)

The famine that followed in Ireland was relatively more devastating than the more famous one a century later.

@zhou

Apologies, I did not mean to irritate you or anyone else.

Re Future climate in Ireland – I admit I have not a clue. One person who thinks he does is Prof Sweeney-led ICARUS unit in NUI Maynooth, have a look at their charts http://icarus.nuim.ie/data

Looks quite toasty for those of us in East and South – Summertime – 3.0 warmer and 50% less rainfall. That is certainly more like South of France than Greenland.

Pity neither he, you nor I will be around to see if he is right though!

A period called the Medieval Warm period ended about 1200, followed by what is called the Medieval Cold period – in fact, that lasted until 1900 & the average planetary temperature was about 0.5C colder than 1960-90.
[from Maslin, “Global Warming: A Very Short Introduction”]

The Medieval Cold period saw the end of the Norse colonies in Greenland, and (possibly) affected the rolling back of the English colony in Ireland.

I have no reason why the 1739-41 was so cold – it also affected North America, where in 1740-41 rivers froze as far south as Connecticut and remained so until April. Possibly, a volcano erupted in a remote part of the globe & caused a mini-nuclear winter. If you go to this site, http://www.kilkennyweather.com/index.php/reviewoftempsto1659 you will find temperature records going back to 1659 from central England (taken from proxy data before records were available). Note that the early 1880s also had a savage winter – that may have influenced the distress that led to the Land League.

The point about 1740 is that it is clearly part of the same climate – it is an outlier, but maybe it just was a 1/250 year event. Things reverted to normal immediately – “regression to the mean winter temperature” as the statisticians put it. That may not be so for the data after 2000, which seems to me to show a rising trend.

Brendan, would you care to comment? These data are much more relevant than what you & JtO were presenting.

Observations for fifty two years at one weather station may not have much significance for global weather/climate trends, but the lack of evidence for warming in Dublin surely merits more attention than it receives in Irish discussions of climate change.

My. Good. God.

(No other comment is necessary, unfortunately)

Wikipedia has an interesting article on the Medieval Cold period a.k.a. the Little Ice Age. The winter of 1739-41 are not mentioned, but there are many examples to show there were many instances of extremes of winter cold in the Northern Hemisphere between the 17th & 19th centuries.

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

A few light taps upon the pane made him turn to the window. It had begun to snow again. He watched sleepily the flakes, silver and dark, falling obliquely against the lamplight. The time had come for him to set out on his journey westward. Yes, the newspapers were right: snow was general all over Ireland. It was falling on every part of the dark central plain, on the treeless hills, falling softly upon the Bog of Allen and, farther westward, softly falling into the dark mutinous Shannon waves. It was falling, too, upon every part of the lonely churchyard on the hill where Michael Furey lay buried. It lay thickly drifted on the crooked crosses and headstones, on the spears of the little gate, on the barren thorns. His soul swooned slowly as he heard the snow falling faintly through the universe and faintly falling, like the descent of their last end, upon all the living and the dead.

From the short story “The Dead” by James Joyce.

So this is not the first country-wide snowfall in Ireland.

@JeromeK

There are quite a few things I’d disagree with in your post, but there’s one point which is particularly common and objectionable. Aside from the assumption you have that Ireland would simply move up a few degrees to a climate like that of Southern France, you assume that it’s the end result of a period of climate change which matters.

It’s not. Climates shift all the time, some with desirable results, some with less desirable results. The issue with the current trend of anthropogenic warming is not that the end result of it would be bad, but that the pace of change (in whichever direction) would be harmful. There are significant costs associated with adaptation and climates shifting, most directly and immediately in agriculture, which is a significant Irish industry. Even if one was to buy the idea that climate change would shift Ireland to a more hospitable and balmier temperature, you should recognise the destructive effects that such a change would have on infrastructure, culture, ecology and agriculture. The costs associated with such a shift (even were we to be certain what that shift is) are likely to be massive.

@Toby
Thanks for the link. You will agree that there is an element of “global warming is occurring regardless of what the recent weather has been” about the commentary.
The distinction between “climate” and “weather” reminds me of the economists’ maxim that the long run is made up of a series of short runs.
I note that the BBC chap says “climate” is what happens on average over a 30-year period, so I am glad that my graph covered 52 years!
By the way, in a little book called The Climate of Ireland by P. K. Rohan published by The Stationery Office in 1975 I came across a table giving the average mean temperature at Dublin Airport for the years 1948-67 as 9.4 degrees C. The value recorded for 2009 was 9.5 degrees.

@Brendan,

“By the way, in a little book called The Climate of Ireland by P. K. Rohan published by The Stationery Office in 1975 I came across a table giving the average mean temperature at Dublin Airport for the years 1948-67 as 9.4 degrees C. The value recorded for 2009 was 9.5 degrees.”

So, given all that has been written, your point is ….. ? Or do you have one?
Is the climate science world supposed to shocked, startled, ashen-faced? Is there a deep significance to this single temperature observation at Dublin Airport that I am missing?

Toby

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