Uncharted Territory

September 23, 2011

Drill Ice, Baby, Drill Ice – Reflections on Clive Oppenheimer’s Eruptions that Shook the World

Filed under: Global climate trends, Global warming, Science, UK climate trends, Volcanoes — Tim Joslin @ 4:03 pm

Clive Oppenheimer notes in his Acknowledgements that he “planned to finish writing this book in 1999!”. Whilst I found Eruptions that Shook the World very informative and readable, it would have benefited from just a bit more effort. For example, the date of the El Chichon eruption is referred to in several places as 1985, though in others, correctly, as 1982 (as I’m sure I read in some other review, though even Google can’t help me out here). More substantively, there is some repetition and an immense amount of cross-referencing. I would also have preferred the inclusion of a comprehensive list of eruptions rather than (or as well as) the superficial details that are included between the Preface and the Introduction and as Appendix A, which excludes the large category of Unknowns and many other events discussed in the book (some of which are in the earlier table). As well as being an incomplete reference source, the book has the feel of being a final draft rather than the finished article.

Most annoyingly, of recent eruptions of which we obviously have the best data, Pinatubo (1991) is discussed in detail (p.54-69), but El Chichon (1982) is referenced only in passing and Agung (1963) hardly at all. In particular, there seem to be important differences between the climatic effects of the El Chichon and Pinatubo eruptions, which would have been worthy of discussion.

Nevertheless, Eruptions fills a gap between school-level and academic material and anyone interested in the subject will find it a stimulating read. Some other reviews are listed here, though how carefully Kate Ravilious read it for New Scientist is in some doubt as she seems to think Oppenheimer discusses “thick layers of ash in Greenland ice cores” rather than the varying sulphuric acid fallout in the cores.

I should say that whilst I read Eruptions to better understand the effects of volcanoes on the climate, the book does discuss the other nasty things volcanoes can do to you, and a great deal more besides.

Minor gripes aside, I presume Oppenheimer’s account reflects the current state of academic thinking about the effects of eruptions on climate. It is this about which I have concerns, that is, the science itself, rather than Oppenheimer’s account of it.

Let me outline what appear to be the central tenets of the current paradigm, and comment as I go along:

1. The climatic effects of eruptions are entirely due to sulphuric acid aerosols.
Volcanoes eject varying amounts of sulphur in the form of sulphur dioxide and hydrogen sulphide into the atmosphere at varying heights and in varying proportions to the total amount of ash, lava and other material. The sulphur reacts to form sulphuric acid aerosols which can remain in the stratosphere for months to years, where they reflect light (and absorb heat, which helps keep them aloft). There is therefore a “recipe for a climate-forcing eruption” (Eruptions, p.69ff).

Eventually the sulphuric acid aerosols descend, and a historic record of sulpuric acid loading can be derived from ice cores, principally from Greenland and Antarctica. Oppenheimer draws on work at Rutgers University by Chaochao Gao, Alan Robock and Caspar Amman (presumably et al – this must have ben a lot of work) to produce an ice-core volcanic index (IVI). He reproduces Gao et al’s graph (as Fig. 4.6, p.98), which I kept referring back to. Here’s my copy-paste from Rutger’s site (for some reason there are spurious double lines on my version – check back at Rutgers if confused):

The IVI replaces H.H. Lamb’s famous Dust Veil Index (DVI). The idea that particles of dust as opposed to sulphuric acid could reflect light away is rejected entirely, or at least the effect of dust is considered insignificant. I find this assumption dubious. For example, the eruption of Huanyaputina in 1600 apparently had catastrophic effects on the climate – causing the Great Russian Famine – yet was, according to the IVI, only about twice as severe as Pinatubo, which really didn’t have a huge effect. Its sulphur emissions are dwarfed by those of Tambora in 1815 and Kuwae in 1452, yet it seems to have had at least as much of a cooling effect. Unfortunately, instrumental temperature records don’t go back to 1600, so we have to rely on anecdotal evidence. Here’s what Brian Fagan says in The Little Ice Age (p.104):

“The volcano discharged at least 19.2 cubic kilometres of fine sediment into the upper atmosphere. The discharge darkened the sun and moon for months and fell to earth as far away as Greenland and the South Pole. Fortunately for climatologists, the fine volcanic glass-powder from Huanyaputina is highly distinctive and easily identified in ice cores.

Huanyaputina played havoc with global climate. The summer of 1601 was the coldest since 1400 throughout the northern hemisphere… Summer sunlight was so dim in Iceland that there were no shadows.”

It seems to me at least plausible that the effect of eruptions on climate is due to dust particles as well as sulphuric acid aerosols. Indeed, my main problem with the IVI (see the paper Gao et al, 2008, which is available to download as a PDF from the Rutgers site) is that not enough has been done to establish how closely ice core sulphate levels correlate with climate impacts of volcanoes. As well as the possibility that there are significant effects due to other kinds of particle, there are other potential complicating factors:

  • varying proportions of stratospheric sulphuric acid aerosol may end up in the ice, so that the IVI only gives an indication of the severity of the climate impacts of the eruption;
  • the amount of sulphate in the ice gives no indication of how long it remained as sulphuric acid aerosol in the atmosphere – obviously the amount of sunlight reflected away is a function of time as well as aerosol density;
  • some of the sulphate in the ice may not have reached as high as the stratosphere to cause significant climate effects (this must surely distort the figures for Icelandic, such as Laki, 1783, and Alaskan eruptions).

We have a lot of data on recent eruptions, which would seem to provide a means of establishing the usefulness of the IVI, which might be a good idea before translating it into a dataset to be plugged into climate models, as Gao et al have done. I can see the appeal of such a mechanistic approach, but it seems to me that the effects of different eruptions vary more than a single variable (OK in most recent cases we also have a date, or at least a season) would seem to suggest.

One problem with the IVI is that although it includes Pinatubo (1991), it does not include El Chichon (1982) because not enough of the Arctic ice cores were old enough, and there is no signal for El Chichon in the Antarctic (I’m unclear why a full signal for Pinatubo is apparently included). This misses a golden opportunity to validate the data. Clearly we need to get out to Greenland and drill more ice cores before the whole lot melts.

A further problem is that the IVI does not explain all of the data. For example, the cold period in the 1690s, including the exceptionally cold summer in 1695, as well as the record cold summer of 1725 (see my recent post on the cold summer of 2011) are completely unexplained. Note that the 1690s has long been a problem. Lamb interrupts his DVI list to discuss it (note the criticism of subjectivity which may affect the whole DVI – the eruption data may be deduced from the weather data rather than independent of it). Here’s a screen grab of part of the DVI which is accessible on Google Books:

Excerpt from Lamb, Climate: Past, Present and Future

More recently, I’d understood* that the dip in temperatures at the start of the 20th century was due to the Santa Maria eruption of 1902 (not to be confused with the famous Mount Pelee eruption of the same year, which is notable for causing a large number of fatalities). But there is only a small signal in the Gao et al data for 1902 (3.77 compared to 30.09 for 1991, the year of Pinatubo, limiting Gao et al’s spurious accuracy perhaps less than I should!).

* e.g. in the IPCC figure produced in a previous post.

2. Eruptions may affect only one hemisphere.
Tropical eruptions can have effects on both hemispheres, depending on (apart from the characteristics of the eruption and the weather at the time) latitude and time of year (and hence the position of the inter-tropical convergence zone, ITCZ). In their paper, Gao et al in fact separate out the hemispheric sulphate records:

Pinatubo affected both hemispheres, but El Chichon only the northern hemisphere (NH). El Chichon, though, seems to have reflected away at least as much heat, having produced a volcanic cloud “extending from the Equator to 30 deg N for more than 6 months, and then gradually spreading more widely” (Alan Robock, 2002, PDF). We can see this first in the atmospheric transmission of solar radiation record from Hawaii:

and, more to the point, in the record of oceanic heat content, where the dip in the early 1980s seems to have been greater than that in the early 1990s (though perhaps already underway by the time of the eruption):

So, if El Chichon removed more heat from the oceans than Pinatubo, and removed the bulk of it from the NH, you might expect some kind of effect on the Arctic ice. Here’s the annual ice extent for August 1979-2011, from the (US) National Snow and Ice Data Centre (NSIDC):

1983 and 1991 both seem to be above the annoying blue trend line (I always feel you need a better reason for drawing lines through data than that you feel like it!), but one might expect the effect to take longer than one year to play out. Indeed, if you imagine replacing the annoying blue line with one from around the turn of the millennium when one might suppose the effects of the two eruptions to have played out, the trend would seem to be a lot steeper. Maybe this tells us nothing more than that the eruptions cause a bit of an ice melt backlog, but I just thought I’d throw that point in.

Perhaps resolving the puzzle a tad, Realclimate have helpfully drawn my attention to ice volume data from PIOMAS, which I copy here purely for convenience:

This perhaps shows more clearly the greater effect of El Chichon (1982) than Pinatubo (1991) on the Arctic ice, though, again, we have trend-lines that confuse the issue, and, again, the eruption occurred somewhat after the temporary ice volume minimum at the start of 1982, and could not have influenced ice volume until at least mid-1982. Notwithstanding, if, here, one ignores the blue line and confidence-interval shading, one might postulate that the combined effect of the two eruptions was to negate any ice-melt that would have otherwise occurred – due to global warming and the fact that if the ice builds after eruptions, logic suggests that it must melt in their absence – for almost two decades, from 1982 to the turn of the millennium, and tentatively conclude that we’re now playing catch-up.

3. Tropical eruptions are climatologically more important.
The theory (Eruptions, p.72-3) seems to be that high latitude eruptions have less effect on climate, though time of year is obviously critical. Although Laki (1783) had dramatic effects on the climate, at least for a year or two, it was a very large eruption.

Oppenheimer briefly mentions the case of Kasatochi (August 2008), a moderate sized sulphur-releasing eruption in Alaska, and the most significant climatologically since Pinatubo (1991). Sure enough, you can see the signal in the Mauna Loa, Hawaii record, above (now I realise I should have numbered the figures). And here’s the possibility of an effect in another ice extent representation from NSIDC:

Not very conclusive**, but maybe the ice did start to re-form a bit quicker than usual in 2008.

** See also the Postscript to this post.

4. The climatic effects of eruptions last only for a few years.
There seems to be an emphasis in the literature on the short-term effects of eruptions. Presumably this is because an event, such as the eruption of Pinatubo, attracts a burst of interest – and generates a flurry of publications – for a few years, before everyone moves on to other projects. Oppenheimer (p.76), suggests forcing lasts around 3 years, after which aerosols disperse, temperature is affected for around 7 years, and sea-ice “perhaps for a decade”. But, he says, oceanic circulation “can be perturbed for up to a century”. Surely this in turn would affect climate? The emphasis on transient effects seems to conflict with the reconstructions of historic temperature records, when, I understood, the main explanation for century-scale variability (the Little Ice Age and all that) is the pattern of natural forcings, principally volcanic eruptions. The story doesn’t appear to be entirely straight, and perhaps this is due to an emphasis on debunking the idea that supervolcanoes (such as Toba 73kya) could have plunged the Earth “back into the ice age” (Oppenheimer, p.190ff).

5. The climatic effect of eruptions scales less than linearly – larger eruptions do not have a proportionately greater effect.
The theory (Oppenheimer, p.191-2) seems to be that larger eruptions produce so much sulphur that larger sulphuric acid particles form, which descend through the atmosphere quicker, so that larger eruptions (as indicated by the sulphuric acid loading in ice cores) do not have proportionately greater effects on the climate.

This all seems a bit speculative. I would have thought a sufficient explanation was that, assuming larger eruptions don’t affect the atmosphere for longer than less extreme events (you’d expect similar sized particles to descend at a similar rate however many of them there are), it seems impossible for effects to scale, given the amount of sunlight reflected away by even relatively small eruptions like Pinatubo and El Chichon (see the Mauna Loa diagram, above, again!). After all, there’s only so much sunlight to reflect away, so (as for greenhouse gases) the energy gain (negative in the case of volcanic aerosols) will be a log function of concentration.

6. The effect of eruptions is to produce cool summers and mild winters.
Except when they don’t.

This is a very confusing aspect, perhaps complicated by the small sample size of recent eruptions. There’s also a need to clarify what is meant.

It’s certainly true that it’s rare for the year of an eruption to experience a cold NH winter. This is what I naively expected when I first started looking at the Central England Temperature (CET) record – eruptions cool the planet, so winter should be colder, right? But in fact cold winters do not immediately follow eruptions, with one notable exception – 1784 after Laki, which also produced a hot summer (Oppenheimer devotes his chapter 12, The haze famine, p.269ff to this event, a repetition of which would, even, or maybe especially, in the 21st century, present serious challenges to health, transport – especially air – and agricultural services in Europe and maybe the entire Northern Hemisphere).

The general story seems to be that eruptions produce more zonal weather at least in the short-term, by heating the stratosphere and disrupting poleward heat transport by the large-scale atmospheric circulation. This leads to mild winters in western Europe (i.e. the zonal pattern of westerly airstreams dominates).

It seems to me there must also be an immediate effect on patterns of oceanic temperature and heat content. I’ve noted before that it appears volcanoes can trigger or exacerbate El Nino events, although this seems to be an area of controversy. Among other effects this may tend to produce mild NH winters.

But perhaps there are also persistent effects on patterns of oceanic heat content, thought to determine NH winter weather in particular. For example, there were generally mild winters in the UK at least for more than a decade after Pinatubo. Yet cold winters – and often runs of colder than usual winters – followed a few years after Huanyaputina (1600 – 1607 was extremely cold); the unknown 1809 eruption (General Winter defeated Napoleon in 1812 and 1814 was the last Thames Frost Fair); Katmai (1912 – 1917 was particularly cold); an eruption in 1925 which has a similar ice-core sulphur signature to Katmai (1929 was cold); Agung (1963); and El Chichon (1982). It’s a confusing picture, and it’s possible that these eruptions simply occurred during series of cold winters (e.g. the famously cold winter of 1962-3 was over by the time of the Agung eruption). Nevertheless, a hypothesis might be framed to relate the location (and season) of eruptions and hence their differential effect on ocean heat content in different regions (or just latitudes) to their effect on climate over a decade or more, through intensifying or weakening (or, in the case of the largest eruptions, completely overriding) the underlying multi-decadal cycles, such as the Atlantic Multi-decadal Oscillation (AMO).

Scientists often give the impression that they’ve answered all the questions. It’s often seemed to me that this puts off those most inclined to produce radical new ideas from specialising in the disciplines that seem to be “solved”. That is certainly not the case with the effect of volcanic eruptions on climate. There are more questions than answers. And, if the historic record is not enough, new events to investigate occur every few years. I’ll certainly be keeping an eye out for new developments in the field.

Postscript (2/10/11): Amended post to tidy up section on cold winters following eruptions, adding a reference to the 1809 event (location unknown) and to scale down some of the diagrams so they’re less in your face. Also, the figure below (from JAXA via Realclimate), perhaps shows the more than usually rapid ice build in 2008 more clearly than the NSIDC figure above, though you have top look closely at the spaghetti to see that the 2008 dark green line shows one of the lowest September ice extents in the period covered turning into one of the highest extents by November:


September 17, 2011

Don’t Backslide on Greece!

You know there’s serious trouble when the Economist runs a two-page editorial, in this case proposing “how to save the euro”.

The Economist agrees with most observers that the problem boils down to how to deal with Greece.

Let’s recap.  Greece, a serial defaulter, essentially fiddled the books to understate its debt in order to be admitted to the euro club, hoping for more economic stability.  Then the financial crisis came, and, as the saying goes, the tide went out and the Greeks were seen to be wearing no trunks.  Not only that, there was an Aegean tsunami on the horizon. Luckily, the Germans had grabbed the deck-chairs so the Greeks aren’t on their own.

What are the Greeks, the Germans and the eurocrats (not to mention the IMF) to do?

What baffles me is the current hysteria from all quarters. Decisive action is not required, as for example, George Osborne insists. The Greek debt is a long-term problem which requires a long-term solution. “Decisive action” implies some kind of quick fix. “Decisive action” is the last thing we need.

In fact, I can see things that can be done to mitigate the situation – economic stimulus measures in the less-indebted eurozone, other European (that includes the UK, Mr Osborne) and other global economies – but I simply can’t see how the central problem could be handled any better than it already is. If that’s not what the markets want to hear then the markets will just have to get over themselves. Some problems just have to be lived with.

Let’s consider the alternatives (I’ve previously written about this on Martin Wolf’s blog at the FT, but I can’t even access that right now, as I terminated my FT subscription in protest at them trying to jack up the price).

1. Greece exits the euro and devalues
This would be catastrophic, at least in the short-term. The Economist discusses the possibility and quotes an estimate that such a step would cost Greece 40-50% of its GDP in the first year (though this seems to assume they leave the EU as well). The trouble is, the “mother of all financial crises” that would result would not be confined to Greece. French and other eurozone banks would take a massive hit, with all kinds of knock-on effects. Even if the initial shock could be contained without seriously recessionary consequences for the remaining eurozone countries, it would simply be a case of “who’s next?” – Ireland, Portugal, Spain, Italy, Belgium, France…

2. Greece devalues within the euro
This is the straw that many are now clinging to, including the Economist, but in fact it’s almost as bad as option 1.

First, there’s the moral argument. Why should the beneficiaries of excessive Greek borrowing be forgiven their debts? Greek taxpayers (or non-payers, by all accounts) would escape paying taxes equivalent to the nation’s long-term spending; all Greeks would have benefited from public services that they haven’t fully paid for; Greek public sector workers would have been paid more than the nation could actually afford – the list is endless. The point is, although different Greek constituencies would no doubt blame each other, the entire nation is complicit, though pre-school children can legitimately claim not to have been in a position to influence matters overmuch.

Second, if Greece is let off a large chunk of its debt, why wouldn’t other countries demand the same? Why should the Portuguese, Spanish, Italians, Irish, French and Belgians suffer tax rises and cuts to their public services if Greek debt is simply written down?

Third, and critically, there’s the problem that a Greek default within the euro doesn’t actually solve the underlying problem. It does something about the debt, but not the deficit. If Greek debt is (say) halved from around 140% of GDP to around 70%, they will still not be credit-worthy, because they’d still be running a deficit. There would still be a need for the IMF, EU and ECB troika to help the Greek government somehow bring revenue and expenditure into line. There’d still be a need for wealthy Greeks to pay more taxes, the Greek public sector to spend less and its economy somehow to grow. In the meantime there’d still be a need for someone to lend euros to Greece.

A Greek default within the euro would simply not have the usual effect of sovereign defaults because it would not be accompanied by devaluation.

In fact, the main effect of Greek default within the euro would be for the Greeks to say “thank you very much”. There’d still be a big hit on eurozone banks (including the Greek ones which would need to be recapitalised from somewhere, and not to mention the ECB), although not the automatic loss from lending to the Greek private sector that would occur in the case of option 1 (when devaluation would make it more difficult, to say the least, for Greek companies to service euro-denominated debt).

Now, it seems to me the troika must recognise this. If I was them I’d demand the budget reforms before allowing any kind of Greek default. In particular, the possibility of Greece having to leave the euro needs to be still on the table. In fact, it wouldn’t surprise me if there hasn’t been a nod and a wink to the off-message officials and politicians (usually German) who regularly float this possibility.

It seems the next payment to Greece is being put off to the last possible moment, even though stumping up is much better for everyone than the alternatives. What puzzles me is that the markets don’t recognise that this brinkmanship is a necessary part of the strategy of forcing Greece to balance its budget in the long-term.

What the Greeks should really be worrying about is the possibility that they haven’t resolved their fiscal problems by the time the rest of the eurozone has recovered (and in particular the banking sector has rebuilt its capital) sufficiently to withstand a Greek default, euro exit and devaluation. Then the eurocrats might just decide to throw them to the wolves.

Still, I wouldn’t rule out a collective loss of nerve and a Greek default within the euro. We’d have to muddle through somehow. If there’s a double-dip, there’s a double-dip – maybe that’s now the least we can expect; if there are further sovereign defaults, the sun will still come up the next morning; if we do end up calling it the Second Great Depression or a Lost Decade, life will still go on. As I said, some problems just have to be lived with.

September 16, 2011

Off the Buses in Ealing

I reported yesterday that TfL is planning to increase fares on average by RPI+2 each year until 2018, and Travelcard prices by RPI+3 over the same period, the supposed justification being that rail fares are to rise by RPI+3. I briefly discussed the implications of this discrepancy, but had a subsequent conversation which led me to consider a different case.

I don’t know about you, but I always feel short-changed if I buy a season pass for a transport network and then find I’d have been better off paying for each journey individually. How likely is this to happen for someone living in Ealing, but working in central London a) now and b) in 2018?

Case 1: A morning and evening peak commuter
This individual uses the tube during the morning and evening peak and sometimes catches a bus back from the station.

In the following table I’ve ignored inflation and just increased costs by 2 or 3% p.a. So in today’s prices a zone 1-3 Travelcard will cost £41.55 in 2018, compared to £34.80 in 2012.

Year   Travelcard cost       Less 10 peak tube fares      Bus fare cost         No. bus fares to break even
2012         34.80                     34.80 – 10*3.10 = 3.80         1.40                             3.80/1.40 = 2.71
2018         41.55                     41.55 – 10*3.49 = 6.64         1.58                             6.64/1.58 = 4.21

So whereas in 2012 our peak commuter would only have to catch the bus 3 times in 2012 to avoid feeling cheated on a weekly Travelcard, he’ll have to catch it 5 times in 2018. If, like me, he walks to and from the station most of the time, he’ll be in a bit of a dilemma by 2018 as to whether or not to buy a weekly Travelcard.

Case 2: A morning peak and evening peak/off-peak commuter
It gets even worse in the case I actually discussed yesterday. The evening peak is from 16:00 to 19:00, so many people working in London may not actually travel home until off-peak fares apply. If this happens 3 times in a week, then the calculation changes somewhat:

Year  Travelcard cost     Less 7 peak, 3 off-peak tube fares     Bus fare cost   No. bus fares to break even
2012        34.80               34.80 – (7*3.10 + 3*2.60) = 5.30              1.40                     5.30/1.40 = 3.79
2018        41.55               41.55 – (7*3.49 + 3*2.93) = 8.33              1.58                     8.33/1.58 = 5.28

By 2018 this commuter will need to use the Travelcard on more than one bus each work-day (or for leisure journeys) to justify the expenditure.

Personally I feel the Travelcard should be a better deal. In London, it seems, regular tube users are likely to pay as much per journey as occasional travellers. And it seems unfair for commuters to have a dilemma as to whether to by a season ticket or not – I haven’t even discussed the effect of Bank Holidays, leave, sick-days and occasional home-working. This is the opposite of the case for main-line rail commuters who get a tremendous deal compared to the occasional traveller.

From TfL’s point of view inflating the cost of Travelcards relative to pay as you go (PAYG) fares may also not make sense in the long-run. The result may be that more of us in suburban London stop buying Travelcards and instead cut out as many bus and tube journeys as possible. As I said yesterday, “maybe it hasn’t occurred to TfL that people might consume less of their product when they put the prices up”.

September 15, 2011

Off the Buses

Boris has announced the 2012 London Transport fare increases already. Do we always get an announcement at this time of year? Or is our leader trying to get the bad news out of the way as long as possible before the mayoral election in May 2012? I note that the last time I visited this topic was in January this year when the last fare rises actually came into effect. With a bit of luck there’ll be a double whammy with negative stories now and in January 2012.

Let’s get the ball rolling with a negative story, then.

The BBC provides a link to the documents issued by the mayor. I only looked at the first one (pdf), which seems to tell me everything I need to know.

It turns out that TfL has a Business Plan based on fare rises of RPI+2%. News to me, most likely totally unjustifiable, but certainly worthy of discussion.

First, are we to believe that TfL’s costs rise faster than general inflation? This seems unlikely, though we do know that many of their employees are extraordinarily privileged to the extent that they apparently deserve a bonus just for doing their job during the Olympics. A lot of people will be working then, and the vast majority will be paid their normal salary, and would expect nothing more. I don’t support the present government, but I was rather hoping they might look at strike law with a view to stopping Londoners being continually held to ransom.

Second, on the customer side, how is it possible to bear continual above inflation rises in transport costs? I’m thinking of low-paid workers travelling into central London. The cost of a weekly Travelcard (tube and bus) season in 2012 will be £34.80 to zone 3, £42.60 to zone 4, after rises of 8.1% in each case. That’s about £1 per hour of work! Surely the minimum wage for central London needs to be higher than elsewhere to compensate? Assuming your pay rises roughly in line with inflation (which is doing well these days), then, if you have to spend more on transport, you have to spend less on something else. That is unsustainable. TfL is not like national rail, which, as the Transport Secretary pointed out this week, is now a service for the wealthy. It is simply not realistic for TfL to increase its prices by more than RPI for a long period of time, unless the lowest wages are increasing by at least the same rate.

So why has TfL adopted the RPI+2% formula? Maybe the document I downloaded doesn’t tell me everything I need to know after all. There seem to be a lot of TfL Business Plans, but the 2009 one for 2009/10 to 2017/18 tells us what we need to know:

“…fares in January 2011 and in subsequent years are now assumed to rise at RPI plus two per cent.”

So it is indefinite. And the purpose is clearly to increase the proportion of operating costs covered by fares and therefore reduce what TfL term “Net operating expenditure”:

Excerpt from TfL Business Plan 2009/10 - 2017/18

Let’s just note in passing that the congestion charge is going to raise less in 2017/18 than 2009/10!

Bizarrely, TfL don’t state what the figures in the table refer to. Presumably they’re 2009 £s (i.e. adjusted for inflation). Assuming that is the case, TfL assumes a steady growth (several % p.a. varying erratically) in passenger numbers as well as a 2% annual increase in the fares. They say:

“As the economy recovers from recession, it is projected that demand will return to current levels by 2012 and then continue to grow strongly as London’s employment and population increase, with demand reaching record levels by the end of the Plan.”

This is a fairly heroic assumption, as it seems to assume a very low elasticity of demand – maybe it hasn’t occurred to TfL that people might consume less of their product when they put the prices up. I’ll return to this point in due course.

TfL’s Business Plan suggests they expect costs to also rise by several % p.a. more than inflation, and also erratically, with a bigger increase in 2012/13 presumably to reflect the need to bribe the staff not to disrupt the Olympics, and in 2017/18, perhaps because Crossrail comes onstream (though there is no concomitant increase in fare revenue).

So in answer to my earlier questions, it seems that unlike every other field of economic activity, running London Transport becomes less and less efficient with time. And low-paid London commuters are expected to pay an ever-increasing proportion of their income on transport.

It seems to make sense that the fare-payer should cover the cost of the service, but let’s make a few observations:

1. Unlike many others, the London transport market is not segmented, so that those who can pay more do (compare walk-on national rail or air fares with advance tickets). I’m not saying I’m a fan of dramatic market segmentation. It creates its own problems, such as making urgent travel punitively expensive for everyone. But in an unequal society, it does allow some access to services for the less well off. Obviously it’d be better to have greater income equality in London, but until that happy day, subsidising fares helps alleviate the problem.

2. The fare-payer is not the only beneficiary of the London transport network. Just as, in the ’80s and ’90s, out of town superstores and malls benefited from the motorway network, such as London’s M25, (and generally improved roads), so the new millennium has seen similar developments – notably London’s twin east and west Westfields (or perhaps the new one should be an Eastfield?) – piggybacking on the city’s public transport network. Maybe these businesses should chip in and subsidise fares from the taxes they and their customers pay.

3. Just as for customers, businesses benefit from the availability of employees. They don’t pay a higher minimum wage even for staff having to travel into the centre of London. Maybe they should, but in the meantime it doesn’t seem entirely unfair for businesses and higher paid employees to subsidise the fares of the low-paid through the tax system. £1 travel cost for each hour of work is a lot for those earning little more than the minimum wage of £6/hour.

4. Today’s fares shouldn’t subsidise investment. That should be paid for by future fares, i.e. the beneficiaries of the investment. And in fact, the goal in TfL’s Business Plan is not apparently to increase fares to pay for more investment. So when Boris mentions investment in the same bluster as higher fares he’s actually being misleading and trying to deflect criticism.

And on top of this, there’s an anomaly in the pricing scheme – this is what really got my goat and prompted me to delve into the mire of transport fares once again:

“Travelcard season prices increase by 8% overall because of the link with National Rail fares which, as approved by the Secretary of State for Transport, are to rise by 8% (RPI+3%).”

What tosh.

Fares other than Travelcards are going to increase by RPI+2% (7% this year), but Travelcards are going to increase by RPI+3%, because you might get the train.

Do they think we’re stupid?

The price for a mainline train within London is the same as the price for the same journey by tube. I can go to Ealing Broadway and get a train to Paddington or I could get the tube there. I’d touch in and touch out with my Oyster card the same either way.

The daily limit applies just the same whether I use tubes and buses or tubes, trains and buses.

No, increasing the weekly limit faster than other fares (and remember this won’t happen just this year, but indefinitely until the policy changes) affects certain people disproportionately. The sort of people most affected are those who use the system most, that is, those dependent on it most likely to get to work, that is, those with least choice.

I’m in zone 3. If you need to get a bus and tube to and from work – and tube stations are thin on the ground out here, so often a long walk – then you’re going to need a weekly Travelcard (£32.20 in 2011; £34.80 in 2012), given that 10 peak pay as you go (PAYG) zone 1-3 tube journeys alone cost £29 in 2011 and £31 in 2012.

Of course, the tragic thing about all this is that many Londoners get the bus all the way into the centre to save a few pounds at the expense of perhaps an hour a day. But even they’re being screwed. The cost of a 7 day bus and tram pass is rising by 7.3% from £17.80 in 2011 to £19.10 in 2012. I can understand why the individual bus fare is increasing by 7.7% – that’s to keep a round number (£1.40 in 2012 after £1.30 in 2011). But £19.00 for the weekly pass would have been a 6.7% increase. Why not stop there? Gratuitous.

As far as I can see, the main beneficiaries of the fare changes for 2012 are off-peak occasional tube travellers for whom the zone 1-2 fare rises by only 5.3% (£1.90 to £2 – OK a nice round figure) and the zone 1-4 fares by a mere 4% (£2.50 to £2.60). For the last, £2.70 would only have represented an 8% increase. It seems fairer somehow to impact what is most likely discretionary travel a little more and that for people trying to make ends meet a little less.

What else could be done to help the low-paid? Besides fair pay, that is.

Well, here’s another curious anomaly. “Peak” in regard to the daily limit means 4:30-9:30am. That is, if you travel between those hours the daily cap will be the peak rate (£10.80 in 2012, rather than the off-peak £7.80). But if you don’t reach the daily limit and just pay as you go, the peak is 6:30-9:30am and 4-7pm (16:00-19:00). Odd. Why not give people more of an incentive to travel before 6:30am, when presumably there is spare capacity? Why not make the peak daily limit apply only if you travel between 6:30 and 9:30am? Wouldn’t this be sensible demand-management? It would help at least some of those who currently spend more than the off-peak daily limit because they take a bus and tube to work (e.g. in zone 3 in 2012 a pre 6:30am tube fare, a peak return fare and two bus fares would come to £2.60 + £3.10 + 2x£1.40 = £8.50, above the off-peak cap of £7.80 but below the £10.80 peak cap).

The case I’m most interested in is my own, of course. It’s the borderline case, where I may as well walk to and from the tube station rather than catch the 297 (or infrequent E10). If the service were more frequent I might take the 297 to Ealing Broadway. As it is, I never do, because I don’t know how long I’ll have to wait, at least until I get to the stop, when there may be a few clues. When I come out of the station, though, I can sometimes see the bus waiting, or at least a queue of people. I’d take it more often if they actually bothered to display a departure time. But sometimes it comes down to a cost consideration. Basically, I’ll rarely pay the full fare. I might take the bus, though, if I reckon I’ll hit the daily limit.

I note that for 2012 the daily limits for zones 1-3 are increasing by more than the relevant tube fares. The peak daily limit is going up from £10.00 to £10.80 (8%) whereas the peak tube fare is increasing only from £2.90 to £3.10 (6.9%). And off-peak, the daily limit is going up from £7.30 to £7.80 (6.8%) whereas the tube fare is increasing only from £2.50 to £2.60 (4%).

So, in 2011, an off-peak return tube journey to the centre, and a journey within zone 1 (£1.90) came to £6.90, leaving 40p of the daily limit to be taken up by a bus fare, but the same itinerary in 2012 would come to £7.20 before the bus, which effectively costs me 60p. OK, it’s a 50% price increase but I expect I’ll still hop on a 297 at Ealing Broadway station if passengers are boarding!

Nevertheless, if TfL persists in increasing weekly Travelcard prices by more than other fares, there will be people who switch to pay as you go, and walk to tube stations rather than take the bus. Maybe this is all very healthy, but it seems a strange policy. It would make more sense to me to raise all TfL prices by exactly the same percentage and charge – now that it’s all electronic with Oyster – to the nearest penny if necessary.

September 3, 2011

How unusual was the cool UK summer of 2011?

Filed under: Global climate trends, Global warming, Science, UK climate trends — Tim Joslin @ 7:05 pm

Why do so many in the media feel they have to get their story in before the final whistle? It’s always a risk. Towards the end of August, a number of articles, typified by this one in the Guardian, trumpeted 2011 as “the coldest summer since 1993”. Political correctness is the order of the day – judging from the figures quoted, the record refers to the whole of the UK. I prefer to use the Central England Temperature (CET) record, which goes back further, to 1659. And I waited until the final data was in (there’s always a delay at the end of the month before the Met Office provide the final figure) and updated my spreadsheet. Here’s my latest summer temperature graph:

CET for Summers 1660-2011 (smoothing shown at central point of date range)

Note that my running means (smoothing) are shown centred, i.e. for the central of the 5, 11 or 21 years averaged. I tried the possible alternatives (i.e. trailing and forward – the latter to try to see the effect of events, such as eruptions), but this representation seems clearest to me. This way, you can most easily see the effect of, for example, the mystery eruption of 1809 and the Tambora eruption of 1815, with all curves dipping at about the same time.

I was expecting to be writing that a comparison with 1993 is not a level playing field, since the eruption of Pinatubo in 1991 cooled the whole planet for a few years (see the graphs from James Hansen that I posted in 2010), making 2011 more freakish, since there hasn’t been a recent eruption. But, in the CET record at least, summer 2011 was in fact colder than 1993.

As the graph shows, there were some colder summers in the mid 1980s, but, again, the whole planet was cooled a tad at that time by the eruption of El Chichon in 1982.

So you have to go back to the 1970s to find a summer cooler than 2011 that wasn’t induced by a volcanic eruption.

Still, you can expect the coldest summer in 40 years every 40 years, so on this reckoning 2011 was not that exceptional – compared to, say, December 2010.

But let’s go a little bit further and take global warming into account. Because of global warming we’d expect warmer summers. Indeed, as the graph shows, prior to 1933, the CET summer mean had only exceeded 17C twice (in 1826 and 1846). The mean CET touched 17C in 1933 and edged past it in 1947. But in the last 40 years it has passed that mark on 5 occasions: 1976, 1983, 1995, 2003 and 2006. The 5, 11 and 21 year running means have all broken new ground.

We should really judge the freakishness of 2011 against the prevailing summer temperature. The trouble is, we don’t know whether temperatures will continue to increase, level off for a decade or two, or even dip – that’s why the 11 and 21 year running mean curves stop before they get to the present day. If summers over the next few years are as warm as from 2003-6, then 2011 will look very unusual – perhaps the most atypical summer since 1860, which was more than 1.5C cooler than might have been expected.

On the other hand, if it turns out that the atypical summers were 2003-6, and temperatures level off for a while, then summer 2011 will just represent the sort of anomaly that might be expected every few decades, rather than a once a century or two event.

Regardless, 2011 is a long way from matching 1725 as the most disappointing summer in the CET record. 1725 was even cooler than 1816, the “year without a summer” following the Tambora eruption!

So, 2011 was surprisingly cool, but not unprecedented.

Incidentally, anyone who followed the link to my previous post which looked at global temperature data might have noticed that the graph of the mean summer UK CET record is uncannily similar in shape to that of (annual, not just summer) Northern Hemisphere (NH) temperatures as a whole.

For more convenient comparison here’s a more recent graph (i.e. including 2010) from the GISS graph site (we’re primarily interested in the solid red line representing the 5 year running mean NH temperature):

The hemispheric temperature record from GISS

Note how, in both graphs, the temperature peaks around 1900, then dips (usually attributed to the 1902 Santa Maria eruption), rises from around 1920 to a peak around 1940, dips again to 1970 or so, then rises into the new millennium. Overall, the magnitude of UK summer temperature changes is about the same as that for the NH as a whole, though the 1930s to 1940s peak is a little more pronounced. So it’s not just UK summer temperatures that vary – as I said, in comparing summer temperatures for freakishness (rather than trends), we need to take account of global warming.

Note also the effects of the eruptions of Pinatubo (1991) and El Chichon (1982) on the NH temperature record (or at least the dips in NH temperature following the dates of the eruptions!). This justifies my decision to exclude 1993 and the mid 1980s summers from the comparison with 2011.

I recently visited my storage unit and discovered that some boxes had fallen and damaged a fan I bought in response to the heat in, I think, 2005. The fan had been gathering dust for a few years – I haven’t needed it. The fact that I’ve paid to store the thing surely shows, though, that I certainly didn’t expect such a change from 2003-6, when all summers exceeded a mean CET of 16C, to 2007-11 when none have (the sudden dip in summer temperatures is clearly shown by the green 5 year running mean in the first figure, above). This weather/climate business is sure full of surprises!

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