We’re hearing this word a lot more from climate scientists. A result from Climategate we are told. Now it’s a great step and it appears sceptics and good climate scientists have a lot more in common than we thought (see Josh’s Royal Society adventures). However. I suspect that uncertainty means something very different to different people. To climate scientists it means you’ve got the right answer, even if you are wrong. To me, it means they’re just guessing. Come back when you really know what you’re talking about.

If you say that a cold winter has only a 5% chance of happening and it does, you aren’t wrong. Or are you? By that measure you could assign a possibility to any eventuality and be right 100% of the time. A paper that appeared recently on WUWT looked at a selection of climate sensitivities published in recent years. They range from +0.5°C to +9.0°C. Is that uncertainty or is it not having a bleeding clue? At least when the climate scientists were making a firm statement we could call them on it, now they will just point to the minority prediction. Would the Italian earthquake scientists been saved if they'd put an earthquake at a 10% probability? 30%? 50%? Would it have made it a more useful prediction?

Climate scientists are able to maintain a consensus because their range of possibilities is huge, and growing if the rumours about the new IPCC report are true. Their idea of missing the barn door with the bulldozer is to get a bigger bulldozer, not learn how to drive it properly.

So when does uncertainty become ‘don’t know’ and is a useful concept at all?

If you say that a cold winter has only a 5% chance of happening and it does, you aren’t wrong. Or are you?

Well, if you wait for 100 winters and there turn out to have been 5 cold ones, then you were probably right. Otherwise not. That's thing about predictions, you have to wait and see.

At least when the climate scientists were making a firm statement we could call them on it...

When was that then?

Rhoda

The threat of Oxfordshire having the climate of Bordeaux doesn't worry me much.

"To climate scientists it means you’ve got the right answer, even if you are wrong. To me, it means they’re just guessing. "

Excellent point TinyCO2 which hits the nail on the head, and I totally concur with your view.

Those recent 15, 20, 20, 20, 25 forecasts are clearly just a hi-faluting pseudo-scientific way of disguising the fact that they have no useful information to impart. You could throw a dice and get the same result at considerably less cost than the Met Office and their supercomputers.

Also, it is not good enough to hide behind the "we need a 100 years to see if we're right". No you don't.. There have been plenty of seasons since the late 80s when this scare was kicking off and we should be building a clear picture by now if the forecasts are on the right track or not. How are these percentages working out and where can I see them? Anecdotally they are way off beam and the fact that they are not front and centre of the debate hints strongly that they are not showing any predictive quality.

In my gambling life I run loads of scenarios to test my hunches and see what works best in real time (not hind-casting). I soon cull anything that is not paying its way. If I stuck with a losing strategy as long as these guys I wouldn't have food on the table and would be in the poor house..

"Come back when you really know what you’re talking about."

I said similar to Richard Betts on here once but I think I've changed my mind. The current crop of "scientists" have thrown huge resources at this problem and not remotely come up with anything practical (not surprising really given the problem and relative lack of data) . It's time to show them the door. It's all been a terrible waste of money that could be much better spent elsewhere. We should now call time on this fool's errand of long-term weather/climate prediction. Do we have the management brave enough to do this?

Stick with auditable reliable data collection for now until we've got loads more and close down the rest.

BitBucket ‘We have to wait and see.’

But is that any use to us at the wrong end of history? With CAGW we supposedly don’t have time to wait and see. Why not do nothing and wait and see what happens? I promise to say ‘my bad’ if I’m wrong. Not a very satisfactory offer but it’s pretty much all the climate scientists will do… no on second thoughts, they probably wouldn’t ever admit they’re wrong, just issue a new version of the climate software.

As for climate scientists making firm statements, they’ve used words like certain, incontrovertible or inevitable. Hansen still does. Google them along with global warming and climate and you’ll find plenty of examples including the resignation of Dr. Ivar Giaever from APS for such a flaw. This link gives a good example from pre 2007.

http://usgovinfo.about.com/od/technologyandresearch/a/climatetochange.htm

Admittedly they usually they use weasel words like ‘almost’, ‘nearly’, ‘may’, ‘might’, ‘could’ or ‘probably’. Do those words help society make a decision? Moreover, those qualifiers are often lost when the science is reported and scientists never bother to object.

Rhoda “You can support AGW on a basis of a certain amount of uncertainty but you cannot maintain the narrative of CAGW that way.” Agreed but what figures can we put on those and how many layers of uncertainty makes an answer meaningless?

Take those climate sensitivity estimations that added together range from 0.5°C to 9.0°C. Each comes with it’s own confidence level but I presume that only one method is correct (unless the planet responds differently to CO2 when other factors are involved). Is the method with 95% confidence in the mid range more accurate than the two at the top and bottom with 65% confidence levels? Does it mean anything when other scientists not involved in the research place their own confidence levels on those figures? Are they not just guessing and basing their confidence on their opinion of the original scientists and not on the research involved? And if a CO2 sensitivity is based on paleo work by another set of scientists isn’t the sensitivity scientist doing the same? When a scientist issues a confidence level are they issuing a statement about their own work or all the work it’s based on or both?

And what happens when some of the foundation science is changed or scrapped? eg The change in the tree ring proxy data should immediately have had a ripple effect up the chain, removing papers that use the data until they can be recalculated. Is that going to happen? LOL.

TinyCO2, you object to Hansen etc making statements of certainty because you think they are wrong. And you object to other scientists making predictions couched in probability because they are too uncertain to be useful!

Confused?

What you need is a prediction that everything will be peachy for the rest of your life. I'm sure some skeptics can oblige.

Dung “A more reasonable position would be that many factors are involved in controlling our climate, we think we know some of them but there are many that we do not yet know even exist.”

True, but I suspect climate science is still in denial about what uncertainty means in real terms.

Do people talk about uncertainty in bridge building? Does the architect cover him/herself by having a 95% confidence level the bridge will support itself and the traffic over it? OK there are mistakes made but usually there is a high price to pay for failure in areas other than science. I once went on a course for handling business crises and was told that ignorance of a dangerous fault in a product was no protection from prosecution. Why are scientists exempt from this? Either their output is just an exercise in thinking outside the box or it’s a finished product that has a responsibility to be accurate. Governments are using climate science as a tool to affect the lives of millions. Shouldn’t that tool be subject to similar standards as a lawn mower or a train? At the moment, climate science is still behaving like an academic curiosity. As a tool for policy decision it’s not fit for purpose.

TinyCO2:

Do people talk about uncertainty in bridge building? Does the architect cover him/herself by having a 95% confidence level the bridge will support itself and the traffic over it?

One would hope the designer aims for 100% under "normal" conditions. And the operators have the option of closing a bridge in emergencies. But to aim for 100% under any foreseeable circumstances would cost too much. There will be probabilities involved - of extraordinary flooding or wind or earth movement or heat etc... Just my guess - I'm sure there are architects around who can comment.

"Preaching to the converted", well of course I am LOL but you never know who might be reading. It's why I'm not ignoring Bitbucket. Sometimes a person who disagrees with you, clarifies an idea in your own mind and allows you to express it.

SimonW

Bad gambler does sound a lot like climate prediction. So does bad psychic.

BitBucket “confused”?

Absolutely! Anyone who isn’t confused by climate science isn’t paying attention, but I don’t need a prediction that everything will be peachy for the rest of my life. That’s the green perception of a 288ppm CO2 world. I think the world is hardly ever peachy and often quite crappy. I do know that energy makes a lot of life’s problems smaller.

We are currently in the worst possible position whichever side of CAGW you fall upon. We’re piddling money and public good will on band aid ventures that won’t make a difference to CO2. We’d be broke, powerless and hot, under current policies if Hansen’s most extreme prediction was right.

To move forward climate scientists need to demonstrate skill, not cover all the bases. Until that point I don’t want them to say that everything’s ok I want them to admit they don’t know.

Uncertainty abounds in science, but in climate science by a series of smoke and mirror prestidigitation the climate scientist who prepare the SPMs have managed to give the impression that they can forecast the future using their models. They cannot of course, and when they're called out they tell you that they're not forecasting the future they're running projections of the future.

Here's how they do the doublespeak. Firstly they tell us that with 90 - 100% certainty that the late 20th century warming was caused by human emissions. So that's pretty certain. Then the warming stops for 15 years while CO2 continues to grow in the atmosphere and Dr Phil Jones tells us there must be natural forcings masking the warming, but we don't understand what they are. So we have natural forcings we don't understand cooling the planet, but we don't have natural forces we don't understand warming the planet.

Here's what the IPCC is certain about:

1. ” … In climate research and modelling, we should recognise that we are dealing
with a coupled non-linear chaotic system, and therefore that the
long-term prediction of future climate states is not possible.”

IPCC
From the 3rd IPCC report, Section 14.2 “The Climate System”, page 774.

Mike,

You're right of course, but I for one have found myself in the position of a foot soldier whose woken up to find the enemy in charge of all the commanding heights, but somehow unable to deliver the final, fatal, blow. I have also access to their communications and find them wondering why they can't deliver the final, fatal, blow and blame it on not being able to get their message across. Now this is, to me at least, an indication of the quality of the enemy, in that they have a virtual news blackout, no one can put even the mildest case against them and they have persuaded the entire world, with the exception of a few small redoubts of sanity, that they are right. Yet they can't get the action they require from the governments of the world. So instead of standing back and looking at their position, to see why they can't deliver the final knockout blow, they believe they can win by doing more of the same i.e. trying to scare people into voluntarily going back into the dark ages.

What they don't seem to grasp is that the people on the planet who are accelerating their use of fossil fuels are already in the dark ages and determined not to stay there, so we, the deniers, aren't holding up the final victory, it's the Chinese, Indians, Russians, Mexicans, Brazilians etc. and all the communications improvements in the world aren't going to persuade an Indian living in the slums of Mumbai that things can get worse for him/her.

As for the SPM, it's amateurish propoganda, written by naive scientists who actually believe the politicians will read them and have embellished them with scientific gobbledegook in a juvenile attempt to give gravitas to them. The politicians, of course, haven't a clue what they're talking about, but being politicians, and not given to in depth examination of their briefs, have mistakenly looked to the enviros for translation of the gobbledegook, and duly been told that we are on the brink of disaster and the scientists are telling us that.

There is an upside for us Mike, the upcoming disasters almost certainly won't come to fruition, and eventually the politicians, having followed the advice of the enviros will be turned on by an indignant population, and will duly give the enviros a good kicking for their deceit. Also, I'm afraid, the scientists will themselves feel the wrath of the politicos.

Let's hope so anyway.

It will be a long hard haul Mike, no question of that. I am developing the theory that we have three political parties each being run by the people with the same worldview as the casts of Four Weddings and a Funeral, and Notting Hill, and the identical grasp of science.