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More numbers

Tamsin Edwards has posted some more details about the Climate by Numbers show at the start of next month. Of particular interest is the official blurb for the show:

In a special film for BBC Four, three mathematicians will explore three key statistics linked to climate change.

In Climate Change by Numbers, Dr Hannah Fry, Prof Norman Fenton and Prof David Spiegelhalter hone in on three numbers that lie at the heart of science’s current struggle to get a handle on the precise processes and impact of climate global climate change.

Prof Norman Fenton said: “My work on this programme has revealed the massive complexity of climate models and the novel challenges this poses for making statistical predictions from them.”

The three numbers are:

  •  0.85 degrees – the amount of warming the planet has undergone since 1880
  • 95% – the degree of certainty climate scientists have that at least half the recent warming is man-made
  • one trillion tonnes – the cumulative amount of carbon that can be burnt, ever, if the planet is to stay below ‘dangerous levels’ of climate change

All three numbers come from the most recent set of reports from the Intergovernmental Panel on Climate Change.

Prof David Spiegelhalter said: “It’s been eye-opening to find out what these important numbers are actually based on.”

In this programme, the three scientists unpack what the history of these three numbers are; where did they come from? How have they been measured? How confident can we be in their accuracy? In their journeys they drill into the very heart of how science itself works, from data collection, through testing theories and making predictions, giving us a unique perspective  on the past, present and future of our changing climate.

Cassian Harrison, Channel Editor BBC Four, said: “This 75 minute special takes a whole new perspective on the issue of climate change. It puts aside the politics to concentrate on the science. It offers no definitive answers, but it does show the extraordinary achievements and the challenges still facing scientists who are attempting to get a definitive answer to what are perhaps the biggest scientific questions currently facing mankind.”

Executive Producer Jonathan Renouf said: “Who would have thought there’d be a link between the navigation system used to put men on the moon, and the way scientists work out how much the planet is warming up? It’s been great fun to come at climate change from a fresh angle, and discover stories that I don’t think anyone will have heard before.”

This all looks very interesting and could lead to some revealing questions being raised.

One other point of note. Jonathan Renouf was the producer of Earth: Climate Wars.

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Reader Comments (90)

When these three folk were undergraduates, they regularly wrote letters home saying "Send more money."

Since graduation, they just can't break the habit.

Feb 20, 2015 at 9:01 AM | Unregistered Commentertoorightmate

Now, Now people. Don't get excited. This is the BBC and Renouf. Nothing to see here, move along.

Feb 20, 2015 at 9:12 AM | Unregistered CommenterStephen Richards

So, if you're following this thread, Tamsin, you will now have some idea why we are a bit cynical about this wonder-programme.
We don't trust the BBC because it has already told us — repeatedly — that global warming is a "done deal" and sceptics have no right to be heard.
We don't trust Renouf to make any sort of objective programme on climate given his past form on the subject.
And the three "magic numbers" my colleagues on here have ripped to shreds over the last 50 comments.
We'll watch the programme but don't be surprised if we're lining up the following morning to explain in precise and gory detail exactly why it was a typical BBC load of BS!
Have a nice day!

Feb 20, 2015 at 9:16 AM | Registered CommenterMike Jackson

Now are we talking about used-car salesmen or about used car-salesmen? ;-)

Feb 20, 2015 at 9:22 AM | Unregistered CommenterWijnand

" trillion tonnes – the cumulative amount of carbon that can be burnt, ever, if the planet is to stay below ‘dangerous levels’ of climate change..."

That's the one I am interested in. I wonder who stated this number and if the person has heard of natural sequestration of CO2 by the oceans and by the additional green plant growth made possible by increased atmospheric CO2?

Beenstock, Reingewertz, and Paldor pointed out that it is not the rate of increase of CO2 that counts (% increase) but the acceleration in the rate of increase. They argue that the evidence is in the data itself, something they found by applying the "unit root test".

Beenstock, Reingewertz, and Paldor, Polynomial cointegration tests of anthropogenic impact on global warming, Earth Syst. Dynam. Discuss., 3, 561–596, 2012


Observations show that the present rate of increase in CO2 is greater than the rate of natural sequestration. But as the authors of this the paper point out (at least in the first draft of their paper) is that economic growth must decelerate as China an India proceed with industrialization and with the deceleration of the growth rate, their production of CO2 will decelerate.

Their analysis thus suggests that natural sequestration together with deceleration of CO2 production will gradually ease the climatic impact ot CO2. The Earth is not in for continuous warming but instead warming will level off.

Accelerate means increase in the rate of speed. Decelerate means decline in the rate of speed.


Feb 20, 2015 at 9:30 AM | Unregistered CommenterFrederick Colbourne

Richard Verney wrote:
"How much warming has there been these past 60 years? According to Hadcrut4, about 0.4degC.
See, for example: (the anomaly has risen from ~0degC to +0.4degC during this period).
If half of that is anthropogenic, it means that there has only been some 0.2degC of manmade warming these past 60 years."

Why start at 1952?

Looking at all of Hadcrut4, there is nothing to suggest the planet is doing anything except rebounding naturally from the little ice age....


Feb 20, 2015 at 9:38 AM | Unregistered CommenterNial

I don't think Prof David Spiegelhalter will be very pleased if the program is presented to reflect anything other than what he sees as mathematically robust. And I expect him to be vocal about it. He has a reputation to protect.

I don't know about the others.

Actually highlighting that there has only been 0.8C of warming is a start. If you ask the man on the Clapham omnibus I bet you'd get answers up to 10C.

Feb 20, 2015 at 10:01 AM | Unregistered Commenterclovis marcus

"One trillion tonnes – the cumulative amount of carbon that can be burnt, ever, if the planet is to stay below ‘dangerous levels’ of climate change"
This statement, of course, should have been phrased : 'Is one million tonnes......'. since, clearly, it is a purely speculative statement.

Feb 20, 2015 at 10:07 AM | Unregistered CommenterChristopher Wood

There was a guy who used to come and empty my septic tank. A little tanker, lots of pipes and a pump. All day, every day he did that. Another bloke used to come with the coal. It would be pi55ing down with rain but he would hump 10cwt of coal bags around the back to the bunker. All day, every day right through the winter. Another chap came with milk. 4.40 am, he started. Everyday, rain or shine. One of them died of cancer last year. He was looked after by visiting nurses who turned up in the rain and snow. Every day. Guess what. None of those people are going to be invited on a jamboree to Paris. None of them will appear on the telly. He might have survived but there is not enough money going into bowel cancer gets no money because it is not the "scare of the day". The money goes to climate science to waffle on about 0.85 of a degree change in an unmeasurable environment over 130 years. My feet are colder by two degrees than my head. But not as cold as the 40,000 extra people who will die this year while money is being thrown at these charlatans.

Feb 20, 2015 at 10:48 AM | Unregistered CommenterIvor Ward

clovis marcus the word your missing is 'editing ' done well you be amazed what they cam make someone's views look like.
And afterwards what can they do, complain or disown it , even successful is this the news will have moved on has and no one notices ?

Its not these three mathematicians who making and more importantly shaping the program , but the production staff who have their very own agenda.

Perhaps next time they may think about buying longer spoons .

Feb 20, 2015 at 10:58 AM | Unregistered CommenterKnR

I'd like to see these mathematicians/statisticians discuss this relationship...
...and its implications for the current CAGW narrative.

Feb 20, 2015 at 11:03 AM | Unregistered CommenterDave Salt

Feb 20, 2015 at 9:30 AM Frederick Colbourne

The source of the Trillion Tonnes is Myles Allen et al "Towards the Trillionth Tonne"

Feb 20, 2015 at 11:06 AM | Registered Commenterdennisa

Brains are being damaged by climate obsession all over the world.

Feb 20, 2015 at 11:23 AM | Unregistered Commenterhunter

Coculd we step back a little, & refrain from being sucked into the dubious language used by the warmistas? We don't "burn carbon", it is inert, the "carbon" is merely a by-product of burning refined fossil fuel. Having said that, the only actual fossil fuel being burnt is coal, as we have examples of fossil imprints in pieces of coal. As I understand it, thanks to Uncle Jo, the Russian oil industry went from strength to strength when they viewed oil as a mineral fuel, not a fossil fuel!

Feb 20, 2015 at 11:26 AM | Unregistered CommenterAlan the Brit

Prof Norman Fenton said: “My work on this programme has revealed the massive complexity of climate models and the novel challenges this poses for making statistical predictions from them.”

Revealed to him, that is.

It'll be interesting to see if they make a good fist of demonstrating how uncertain climate science is, how the models are not validated and suchlike but then retreat to mangling the precautionary principle and saying we must cut our emissions anyway. A bit like a Jeremy Clarkson car review when he does actually review cars (rather than cocking about). Spend 90% of the time being objective and then throw that out of the window for the conclusion.

Feb 20, 2015 at 11:31 AM | Unregistered CommenterGareth

I will make two comments.

Both my father and my boss have been involved (as part of the subject matter) in the making of TV documentaries. Both were disappointed and surprised at the final programmes and how the things they knew to have happened and to have been filmed were modified or omitted for the purpose of 'entertainment'. It reminds me of the comment often made about newspapers of 'I trust my paper to be accurate, but any time there is a story where I know the truth it isn't'

Second point is about the three numbers:
1 - 0.85 degrees C. At least this is a factual starting point. There are obviously questions over the reliability of the measured data and over the various procedures used to go from this to the global average, but it is at least a partially science question (although I think a lot is really just accounting).

2 - 95%. As this relates to expert judgement rather than quantification of the data, this is mainly a sociology question.

3 - One trillion tonnes. Well, where to start - value judgements based on assumptions and model outputs. How can you have any certainty when even the IPCC quotes a range of climate sensitivity that varies by a factor of 3. This one is really just politics.

Feb 20, 2015 at 11:55 AM | Unregistered CommenterIan Blanchard

He fails to mention that the same people who are 95% certain are unable to account for why the 0.85 degrees isn't much higher as their models think it should be.

(Never mind that the 0.85 itself is not a measurement, it is the result of a complex calculation whose inputs are of questionable validity and the applied calculations more so.)

Feb 20, 2015 at 12:45 PM | Unregistered CommenterNW

Graeme No.3 --
It's not 100 years to go before the "trillion tonne" mark. Cumulative emissions to date are around half of that, so (at the current 10 Gt/year rate) perhaps 50 years to reach this milestone, fewer if emissions continue to accelerate.

Whether that's the end of the world as we know it -- that's a different matter.

P.S. Definitely read Myles Allen as dennisa mentions above.

Feb 20, 2015 at 12:56 PM | Registered CommenterHaroldW

I am with Stephen Richards, Mike Jackson and a few others here, Once you discover the name Renouf you decide the only reason you might watch it is to check your blood pressure compared to when you watched Climate Wars.

Frederick Colbourne raised another more than relevant point; sequestration of Carbon in the various sinks. The earth has 'previous' on this issue; it once had 800,000 ppm of CO2 but has munched its way through 799,600 ppm. Already the earth has responded to the recent rise in atmospheric CO2; plants are growing taller and stronger, yields on crops are increasing. If the level of CO2 keeps increasing then the planet will produce plants which have an even more voracious appetite for the stuff; it is called Nature. However Nature is not a benevolent kind hearted and generous entity.Nature does not like happy endings, left to its own devices it will keep on removing CO2 from our atmosphere and all life on earth will end. Best estimates are so far that all vegetation will be gone when we get down to around 140/160 ppm so we are not far from what you might (with some sincerity!) call a tipping point. Our opponents ( and do not be deceived by bleeding heart do-gooders; they really are opponents) want to help the earth get rid of the rest of the CO2 ASAP, and they think WE are crazy!

Feb 20, 2015 at 1:09 PM | Registered CommenterDung

The reallly really important number is five.

Why do 100% of Climate scientists stay in five star hotels?

Feb 20, 2015 at 1:45 PM | Unregistered CommenterStacey

Here is climategate email 1683 from Jonathan Renouf, showing just how fair and balanced he is on climate change when he produces his BBC TV programmes.

Your essential job is to "prove" to Paul that what we're experiencing now is NOT just another of those natural fluctuations we've seen in the past. The hockey stick curve is a crucial piece of evidence because it shows how abnormal the present period is - the present warming is unprecedented in speed and amplitude, something like that. This is a very big moment in the film when Paul is finally convinced of the reality of man made global warming.

Feb 20, 2015 at 1:54 PM | Registered CommenterPaul Matthews


Because the hoteliers have not yet realised that there really are people who would be stupid and pompous enough to stay in a ten star hotel :P

Feb 20, 2015 at 1:55 PM | Registered CommenterDung

Paul Matthews

That email was back in 2005, however a few years later (2008) for Climate Wars he states

"All I can say is that I wish the bloggers could have been there as we made the series. I think that had they been with us they would have been reassured at the level of scrutiny that all the scientific claims in the series were subjected to. "

The level of scrutiny that a diehard alarmist would have!!!!!!!!! He pretends to be objective some 3 years after it is clear he is biased!

Feb 20, 2015 at 2:20 PM | Unregistered CommenterCharmingQuark

Feb 20, 2015 at 9:38 AM | Nial

I too share your view that the planet is rebounding from the LIA, or at any rate, a very substantial component of the assessed warming is due to that rebound and/or nothing more than natural variation.

The reason I looked at the warming post the early 1950s is that the programme makers assert with respect to the second number: "95% – the degree of certainty climate scientists have that at least half the RECENT warming is man-made," so I was pontificating on the meaning of "recent" and also how much (claimed) warming has taken place in "recent" times.

The programme will be whatever the programme will be. There is little point in expressing detailed views at this stage, and i prefer to wait and see what the programme says. But like others, I would be very surprised if the programme is objective and talks openly about the uncertainty.

Feb 20, 2015 at 2:20 PM | Unregistered Commenterrichard verney

"In their journeys they drill into the very heart of how science itself works"

I wonder if it will include anything like this from Hadley in January 2005,
"Stabilising climate to avoid dangerous climate change — a summary of relevant research at the Hadley Centre"
Prepared by Geoff Jenkins, Richard Betts, Mat Collins, Dave Griggs, Jason Lowe, Richard Wood

The original is no longer available at the Hadley website but I found a source here at the ultra warm "Consciousclimate", which seems to be a torch carrier for Skeptical Science and Real Climate.

Here it is: Climate Change 1.pdf

From the summary:

"What constitutes ‘dangerous’ climate change, in the context of the UN Framework Convention on Climate Change, remains open to debate"

"Once we decide what degree of (for example) temperature rise the world can tolerate, we then have to estimate what greenhouse gas concentrations in the atmosphere should be limited to, and how quickly they should be allowed to change. These are very uncertain because we do not know exactly how the climate system responds to greenhouse gases."

"The next stage is to calculate what emissions of greenhouse gases would be allowable, in order to keep below the limit of greenhouse gas concentrations.

This is even more uncertain, thanks to our imperfect understanding of the carbon cycle (and chemical cycles) and how this feeds back into the climate system."

In spite of such knowledge gaps, in 2005, with three IPCC assessment reports already on the stocks, and the fourth underway "the science" was already "unequivocal". The UK's own Robert Watson had said so in 1997, see the late Henry Lamb's Kyoto report,,

Watson was then chair of the IPCC, pre Pachauri and "he was asked in a press briefing about the growing number of climate scientists who challenged the conclusions of the UN that man-induced global warming is real and promises cataclysmic consequences.

Watson responded by denigrating all dissenting scientists as pawns of the fossil fuel industry. "The science is settled" he said, and "we're not going to reopen it here."

Feb 20, 2015 at 3:45 PM | Registered Commenterdennisa

The only Miscalculation Climate Scientist made was underestimating the Scientific and Research caliber of the Climate Skeptic community.
They thought they were ignorant ,Eastenders watching, UKIP voting Richard Littlejohn opinion type Sun reading failed Comprehensive school educated oilks like me.

Unfortunatley those 3 percent University of old fart post grads also have Science degrees and are now eagerly sharpening their pencils, oiling their slide rules, wiping their Laptop Screens ,BBC4 IPlayer /Skyplus at the ready and smelling blood .

When Climate Change by Numbers comes on BBC4 the Bishophillbillies will be on top of those particular numbers quicker than a bridegroom on top of a virgin on her wedding night.

"Gamergate" was one bunch PC Nerds defeated by another bunch of Nerds with more and better PCs.
"Climategate" is one bunch of plucky Science nerds taking on the Establishment who may have more politicians and more "concerned" showbiz celebrities but still doesn't make them right.

Feb 20, 2015 at 4:21 PM | Unregistered Commenterjamspid

Oi move along nothing for you Dirty Deniers you are not in the demographic ! ..It'll be just Confirmation Bias Porn for warmists
- TV is usually about entertainment, getting an audience by pandering to the "truth" they want hear rather than proper objective truth that skeptics are interested in.
- Yes if Spiegelhalter was free to speak and the prog maker was Andrew Neil I'd watch, but with Jonathan Renouf propaganda is what to expect..prove me wrong .
( ah @SteveRichards got the same comment on already)

- If the BBC was interested in truth they would have made a big special from that Lovelock blog post in 2010. How come I only found out from @esmiff that his words were so extraordinary and emphatic ?

"the lying, dumb, little rascals who do modern climate science"

- " but there are some sceptics that I fully respect. Nigel Lawson is one. He writes sensibly and well. He raises questions. I find him an interesting sceptic"
...Lovelock's 2010 comments

Feb 20, 2015 at 4:58 PM | Registered Commenterstewgreen

Paul climategate email 1683 from Jonathan Renouf shows his constructed reality TV technique of come up with the narrative first then fake it up telling Briffa the scientist what to say. Instead of being a fly on the wall like the public think

Feb 20, 2015 at 5:09 PM | Registered Commenterstewgreen

They should examine the origins of 97% as well.

Feb 20, 2015 at 9:31 PM | Unregistered CommenterSteve

Ivor Ward,

Your vignette is what also makes me angry, the wasted money, the wasted time and the miss-directed intellectual capacity for the chase of the chimera of global warming is criminal.

Feb 20, 2015 at 10:18 PM | Unregistered CommenterMike Singleton

Stewgreen, so Renouf is a scientific script writer, as well as post production editor. What a useful person for the BBC to have so heavily involved with a programme.

Feb 20, 2015 at 10:27 PM | Unregistered CommenterGolf Charlie

Obvously I won't be watching this insulting drivel, but perhaps someone who does could explain how they justify stating the warming since 1880 to a precision of 0.01C.

As it happens, this is what first piqued my interest in the global warming issue back in 2005 or so. I saw the graph showing minute variations in 'global temperature' going back to 1880 and wanted to understand how it was possible to know such a thing. The top hit on Google was a Climate Audit post discussing 'bucket adjustments', whereupon my curiosity turned to contempt.

Feb 20, 2015 at 10:28 PM | Unregistered CommenterJake Haye

Partly because of your insistence, I was holding onto a ray of hope that your involvement with the BBC might introduce some science into a presentation about climate.

Then the above news is released. That ray had dimmed to less than a glimmer.

Why? By the numbers of course!

1) + 0.85 degrees increase since 1880.
An impossible number! Or have you lost all sense of how significant numbers are derived? Don't forget to take in all of the 'adjustments' as acknowledged error ranges.

2) 95% – the degree of certainty climate scientists have that at least half the recent warming is man-made.
Climate scientists? All of them? Or just the IPCC and green trough parasites?
You really should look into the Oregon Petition; with 31,487 scientist signatures.
Another group you really need to read about are the NASA astronauts and scientists who stood together and sent a joint letter to the NASA Administrator. These people stood up and proclaimed for science, honest ruthless science where mistakes cost lives, not gain approving nods from pals.

3) one trillion tonnes – the cumulative amount of carbon that can be burnt, ever, if the planet is to stay below ‘dangerous levels’ of climate change.
Just what empirical science observations can lead anyone but a quack to make that statement?
Consider, if half of that trillion tons of CO2 are already emitted does that mean one trillion tons will cause a total of 1.3 degrees of warming since 1880?

Don't be absurd! That statement must come straight from the climate witch doctor and their brews and ranks with the 'no snow', 'disappearing glaciers', 'polar ice loss', 'polar bear declines', 'penguin declines', 'bigger deserts', 'more droughts', 'famine' and the multitude of absurd disasters because of climate change.

It is not too late Tamsin. Many of us are still willing to read your thoughts and science, answer questions, consider weather imponderables and generally run theories through their paces.

Stick with those sources of bias and far more than your sanity and honesty falls into doubt. Those folks ruin careers.

Feb 21, 2015 at 3:05 AM | Unregistered CommenterATheoK

Horned Viper: What colours do these three IPPC numbers have in common with BBC purpose?

Clues: Nut & Latte Cake bake-off à la mode. Lip-curling ‘science’ dressed up mid Millennium Bridge on the run-up to a Parisian party. Book your own chamber pot at the nearest shisha house.

Surrealism's alive but under the weather in the BBC climate. Vicky Coren Mitchell will be around shortly to collect Guardian eco-dolts in a big green leccy limo with 24hr on-line poker on heads-up display. Cut to focused-political/stochastic-economics Chief Editor in Vegas for the strip angle. [budget for both but too far out going forward].

If not for mindless bandwidth clamber, why in Gaia would anyone contemplate allowing BT to buy up EE? Place your bets for re-runs of Balderdash and Piffle, yet more spin and sensationalism. All of which any credible scientist is always at pains to limit.

More PC busting satire; less dogma laced soap required. At least sack the twerp running over-acting classes. Hand gestures and stilted speech are slowly turning into unnerving arm waving and creating compression artefacts. Hazel, green and pusssse: odds-on universal truth in the face of chaos.

Feb 21, 2015 at 3:48 AM | Unregistered CommenterAnonymous

Please remember 0.12C per decade is not enough to trigger any action on CO2.

The BBC's environment analyst Roger Harrabin put questions to Professor Phil nJones, including several gathered from climate sceptics. The questions were put to Professor Jones with the co-operation of UEA's press office.

Do you agree that from 1995 to the present there has been no statistically-significant global warming

Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

C - Do you agree that from January 2002 to the present there has been statistically significant global cooling?

No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant.

Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?
An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

Feb 21, 2015 at 3:48 AM | Unregistered Commenteresmiff

Feb 20, 2015 at 6:27 AM | davidchappell

I was just looking up the 'average hottest' place on Earth which Wikipedia has as Dallol in northern Ethiopia. An extreme arid environment so obviously no real water vapour feedback and also a place where people still manage to live in the region. In fact a train line passes very near to it. I don't think the same us true for the coldest place on Earth.

Feb 21, 2015 at 2:26 PM | Unregistered CommenterRob Burton

'One trillion tonnes....'

Not - one trillion and one..?

Seems an awfully convenient number to me...

Feb 21, 2015 at 3:02 PM | Unregistered Commentersherlock1

esmiff you mean Phil the dog eat my data , why should I share information you only want to find something wrong it , excel sorry no idea how that works , Jones. If that is your 'star' witness , your going to have to work hard to find a worse one.
But you got close with Roger , its true because Greenpeace said so , Harrabin

If these two told you the sun will come up in the east tomorrow , such is the level of 'trust' they have created , you still may think about checking it out to be sure .

Feb 21, 2015 at 4:37 PM | Unregistered CommenterKnR


Brother Phil is revealing the truth. There is nothing special about current warming.

Feb 21, 2015 at 4:42 PM | Unregistered Commenteresmiff

Spot on breaks the too good to be true rule

Feb 22, 2015 at 3:33 AM | Registered Commenterstewgreen

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