Climate Change - The Scientific Debate

[QuantumTokoloshi]

plunker said:

We're all banging on about CO2 here mate.

Part of the problem with answering your question is climate sensitivity which I don't regard as known with great precision.

But that is a key part for the AGW argument. More C02 = warming. Global temperatures are sensitive to C02 change. If we do not know the sensitivity with any precision, then why does the AGW hypothesis get any credence at all ?

[Silver Smudger]

plunker said:

Silver Smudger said:

plunker said:

This is always a good illustration of what trace amounts can do optically:

http://www.youtube.com/watch?v=81FHVrXgzuA

An almost completely pointless demonstration, but I do wonder what that demo would look like if you used red ink for CO2 for instance.

... and black ink for water vapour?

You would see the same increasing opacity with any colour surely?

Whoosh!

[dickymint]

plunker said:

This is always a good illustration of what trace amounts can do optically:

http://www.youtube.com/watch?v=81FHVrXgzuA

What an absolute crock of ste.

[plunker]

QuantumTokoloshi said:

plunker said:

We're all banging on about CO2 here mate.

Part of the problem with answering your question is climate sensitivity which I don't regard as known with great precision.

But that is a key part for the AGW argument. More C02 = warming. Global temperatures are sensitive to C02 change.

You seem surprised but climate sensitivity is the big issue and always has been.

QuantumTokoloshi said:

If we do not know the sensitivity with any precision, then why does the AGW hypothesis get any credence at all ?

Probably because the range of estimates for a doubling of CO2 goes from something like 1.5C (significant warming but not that scary) to 4.5C (very scary indeed) with 'best guesses' in the 2.5-3.5 range (pretty scary).

Notes
- Figures culled from a scientific american article about the 2013 IPCC report (cos I couldn't be arsed to trawl thru IPCC reports)
- Scary scale is my own.

[Diderot]

plunker said:

QuantumTokoloshi said:

plunker said:

We're all banging on about CO2 here mate.

Part of the problem with answering your question is climate sensitivity which I don't regard as known with great precision.

But that is a key part for the AGW argument. More C02 = warming. Global temperatures are sensitive to C02 change.

You seem surprised but climate sensitivity is the big issue and always has been.

QuantumTokoloshi said:

If we do not know the sensitivity with any precision, then why does the AGW hypothesis get any credence at all ?

Probably because the range of estimates for a doubling of CO2 goes from something like 1.5C (significant warming but not that scary) to 4.5C (very scary indeed) with 'best guesses' in the 2.5-3.5 range (pretty scary).

Notes
- Figures culled from a scientific american article about the 2013 IPCC report (cos I couldn't be arsed to trawl thru IPCC reports)
- Scary scale is my own.

All of which have as much credence as believing there are fairies at the bottom of the garden. You do realise there's been no warming for over 18 years?

[plunker]

Diderot said:

plunker said:

QuantumTokoloshi said:

plunker said:

We're all banging on about CO2 here mate.

Part of the problem with answering your question is climate sensitivity which I don't regard as known with great precision.

But that is a key part for the AGW argument. More C02 = warming. Global temperatures are sensitive to C02 change.

You seem surprised but climate sensitivity is the big issue and always has been.

QuantumTokoloshi said:

If we do not know the sensitivity with any precision, then why does the AGW hypothesis get any credence at all ?

Probably because the range of estimates for a doubling of CO2 goes from something like 1.5C (significant warming but not that scary) to 4.5C (very scary indeed) with 'best guesses' in the 2.5-3.5 range (pretty scary).

Notes
- Figures culled from a scientific american article about the 2013 IPCC report (cos I couldn't be arsed to trawl thru IPCC reports)
- Scary scale is my own.

You do realise there's been no warming for over 18 years?

No I don't realise that. That would require taking one particular dataset as the 'one true' metric of global temperature which isn't how I like go about things.

[Silver Smudger]

plunker said:

No I don't realise that. That would require taking one particular dataset as the 'one true' metric of global temperature which isn't how I like go about things.

Does that mean that there is more than one data set which is true, and that they are not the same?

[plunker]

Silver Smudger said:

plunker said:

No I don't realise that. That would require taking one particular dataset as the 'one true' metric of global temperature which isn't how I like go about things.

Does that mean that there is more than one data set which is true, and that they are not the same?

No it means if someone wants to go mining through all the available data with a specific goal (in this case to find the longest flat trend) that's up to them but I don't have to accept their findings as a true picture.

[Jinx]

plunker said:

No it means if someone wants to go mining through all the available data with a specific goal (in this case to find the longest flat trend) that's up to them but I don't have to accept their findings as a true picture.

Given as the anomaly itself is a function of the base data chosen I don't think a true picture is ever possible from the data.
But from the situation where all datasets were showing warming where now the majority are showing warm but flat-lining in temps (in direct contradiction of the climate models) it is possible to assume that the current understanding of climate is too poor to base any long lasting political decisions on.
The fear of catastrophic Carbon Dioxide forced global warming should have been reduced by AR5 (it was if you read anything but the summary for policy makers) and therefore knowing we have more than 50 days to save the earth should have been met with better long term solutions.
Instead we get more hysteria and more nonsense based on the upper boundaries of the hypothesis. I do despair.

[rovermorris999]

plunker said:

No it means if someone wants to go mining through all the available data with a specific goal (in this case to find the longest flat trend) that's up to them but I don't have to accept their findings as a true picture.

Do you accept that the models have been wrong and therefore the science isn't settled?

[plunker]

rovermorris999 said:

plunker said:

No it means if someone wants to go mining through all the available data with a specific goal (in this case to find the longest flat trend) that's up to them but I don't have to accept their findings as a true picture.

Do you accept that the models have been wrong and therefore the science isn't settled?

I think the science self-evidently isn't settled or the IPCC wouldn't give a range of estimates and best guesses for climate sensitivity.

If we're still talking about the pause, I'm unconvinced the models are majorly wrong based on that. Too soon to tell imo.

[rovermorris999]

plunker said:

I think the science self-evidently isn't settled or the IPCC wouldn't give a range of estimates and best guesses for climate sensitivity.

If we're still talking about the pause, I'm unconvinced the models are majorly wrong based on that. Too soon to tell imo.

Perhaps you could have a word with the rest of the AGW crowd then please. We are constantly told 'the science is settled' and it patently isn't. The models are way out even with the 'adjustments' to historic data to make them cooler and hence the 'warming' greater.

[Variomatic]

plunker said:

I think the science self-evidently isn't settled or the IPCC wouldn't give a range of estimates and best guesses for climate sensitivity.

If we're still talking about the pause, I'm unconvinced the models are majorly wrong based on that. Too soon to tell imo.

The problem is, if you look at the data as used by the alarmists, the world (roughly) warmed rapidly between about 1978 and 1998. That 20 years was long enough to "tell" that AGW was real. But now we're told that just 2 years less of no, or negligible, warming isn't significant.

Several years ago, the climate community was heard to say that a 10 year pause was conceivable but 15 couldn't happen "according to the models". Then they changed that to 17 years (in any one of the established data sets), we're now at 18 and they're moving the goalposts again - this time without actually saying where they've moved them to!

Anyone who genuinely thinks for themselves must see problems with that. What happens when (for the sake of argument) "the pause" gets to 20 years too? Or 25?

When exactly will be "long enough"? In 100 years time are what remains of humanity going to be sitting in their ice caves with the scientists still saying "don't burn that coal, the warming will be back with a vengeance any century now!"?

[plunker]

rovermorris999 said:

plunker said:

I think the science self-evidently isn't settled or the IPCC wouldn't give a range of estimates and best guesses for climate sensitivity.

If we're still talking about the pause, I'm unconvinced the models are majorly wrong based on that. Too soon to tell imo.

Perhaps you could have a word with the rest of the AGW crowd then please. We are constantly told 'the science is settled' and it patently isn't. The models are way out even with the 'adjustments' to historic data to make them cooler and hence the 'warming' greater.

Whenever I've seen sceptic bloggers saying 'they're cooling the past to make warming look bigger' they're usually referring to early 20th century data but that actually works against AGW as it creates more warming in the 'wrong' part of the record. If you wanted to adjust the data to support AGW you would warm the past to make the late 20th century warming look more anomalous.

[plunker]

Variomatic said:

plunker said:

I think the science self-evidently isn't settled or the IPCC wouldn't give a range of estimates and best guesses for climate sensitivity.

If we're still talking about the pause, I'm unconvinced the models are majorly wrong based on that. Too soon to tell imo.

The problem is, if you look at the data as used by the alarmists, the world (roughly) warmed rapidly between about 1978 and 1998. That 20 years was long enough to "tell" that AGW was real. But now we're told that just 2 years less of no, or negligible, warming isn't significant.

If you look at the data as used by sceptics you'll constantly see them using the 1998 temperature spike as some kind of hinge point as though that's the only 'one true' way of looking at the data

I think warming continued well into the 21st century.

Variomatic said:

Several years ago, the climate community was heard to say that a 10 year pause was conceivable but 15 couldn't happen "according to the models". Then they changed that to 17 years (in any one of the established data sets), we're now at 18 and they're moving the goalposts again - this time without actually saying where they've moved them to!

A few citations required here.

[Variomatic]

plunker said:

If you look at the data as used by sceptics you'll constantly see them using the 1998 temperature spike as some kind of hinge point as though that's the only 'one true' way of looking at the data

I think warming continued well into the 21st century.

Not at all, although there does increasingly seem to have been a turning point in the trend at somewhere around that time.

The 18 years of statistically insignificant / no warming which has been variously described as warming "ending" "pausing", or suffering a hiatius hernia actually starts in late 1996 according to RSS - over a year before the '98 El Nino created a spike.

The various other datasets have effectively flatlined since somewhere between then and about 2001. Given the state of the data that's probably as good as they'll get for agreement, but the fact remains that a steady 20-odd year warming trend before thereabouts has been a steady flat trend since.

That's not "according to sceptic blogs", it's according to the data.

There's a prblem with the warmist insistence on 30+ year trends - apart from the fact that there hasn't been a clear 30 years of warming, and had only been maybe 10 years when they started rining the alarm bells.

IF warming is a continuing linear trend then saying "it's still warming but there's a hiatus" is valid. But that's a very big "if" indeed in a system which we know has had many, many, changes in direction in the past without any help at all from us. And for every year that temperatures remain level (or even start to decrease), the 30 year trend reduces towards zero. We've got over halfway there already, so they really should be admitting to the possibility they're wrong.

Unless, of course, Nature herself is a Denier?

plunker said:

A few citations required here.

You'll have to give me a little time on that because, curiously, any mention of such claims doesn't seem to exist anymore except on what you'd dismiss as "sceptic blogs".

More reliable sources such as the MSM seem to have done quite a good job of disappearing any references to such statements. Which is a shame, seeing as that's where my scepticism started LONG before I'd heard of places like WUWT, Climate Depot etc.

In fact, I wasn't all that interested either way except that I noticed that suddenly the BBC was saying that sceptics were wrong because 17 years were needed, when I clearly remembered their last mention where Dr Jones was saying 15 years.

Then 17 years was suddenly a "misrepresentation" of what had been said - according to the very people who'd said it (in that context) in the first place! Around that point I decided that might start digging for myself rather than blindly trusting the meeja and started finding all the other inconsistencies.

Unfortunately, as a dyed-in-the-woll socialist, to do that I found myself having to associate (and be associated with) fairly unsavoury characters like Monkton. But the truth is the truth no matter who's saying it, so i try not to let my own political views get in the way

Anyway, I'll keep digging to see if I can find a forgotten-to-delete "reliable" source for you but, in the meantime, you could try looking for yourself - pretty sure the 15 year claim was by Phil Jones as a satrting point

[Halb]

durbster said:

For example, with the very real prospect of a global food shortage in my lifetime, I say bring on the GM crops (and/or permanent Mars settlement ).

I say bring on Utopia.

[dickymint]

Variomatic said:

Anyway, I'll keep digging to see if I can find a forgotten-to-delete "reliable" source for you but, in the meantime, you could try looking for yourself - pretty sure the 15 year claim was by Phil Jones as a satrting point

How about.......


"Yet he insisted that 15 or 16 years is not a significant period: pauses of such length had always been expected, he said.

Yet in 2009, when the plateau was already becoming apparent and being discussed by scientists, he told a colleague in one of the Climategate emails: ‘Bottom line: the “no upward trend” has to continue for a total of 15 years before we get worried.’

But although that point has now been passed, he said that he hadn’t changed his mind about the models’ gloomy predictions: ‘I still think that the current decade which began in 2010 will be warmer by about 0.17 degrees than the previous one, which was warmer than the Nineties.’

Only if that did not happen would he seriously begin to wonder whether something more profound might be happening. In other words, though five years ago he seemed to be saying that 15 years without warming would make him ‘worried’, that period has now become 20 years."

http://www.dailymail.co.uk/sciencetech/article-221...

But then "Climategate" emails don't count... do they?

[Variomatic]

dickymint said:

How about.......

[...]

But then "Climategate" emails don't count... do they?

Thanks, but I'm afraid you're right - god forbid that their own exact words, with crystal clear context, should be treated as evidence of what they said! And, in the same vein, the DM itself isn't considered a reliable source by alarmists anyway.

In fact, nothing that publishes anything that might disagree with them is, including several scientific journals over the years! It's a bit like having the Pope as final arbiter of what constitutes a "reliable" religious text

[plunker]

Variomatic said:

plunker said:

If you look at the data as used by sceptics you'll constantly see them using the 1998 temperature spike as some kind of hinge point as though that's the only 'one true' way of looking at the data

I think warming continued well into the 21st century.

Not at all, although there does increasingly seem to have been a turning point in the trend at somewhere around that time. The 18 years of statistically insignificant / no warming which has been variously described as warming "ending" "pausing", or suffering a hiatius hernia actually starts in late 1996 according to RSS - over a year before the '98 El Nino created a spike.

The various other datasets have effectively flatlined since somewhere between then and about 2001. Given the state of the data that's probably as good as they'll get for agreement, but the fact remains that a steady 20-odd year warming trend before thereabouts has been a steady flat trend since.

That's not "according to sceptic blogs", it's according to the data.

And yet the trend from 1978-2006 is greater than the trend from 1978-1998 (or -2001):



1978-1998 (inclusive) Least squares trend line; slope = 0.0174034 per year
1978-2006 (inclusive) Least squares trend line; slope = 0.0187474 per year

No cherry-picking of datasets here, it's the same for Hadcrut4, Hadcrut3, Gistemp, UAH and RSS - the trend increases.

Here's the woodfortrees page link so you can easily change the choice of dataset for yourself:

http://www.woodfortrees.org/plot/hadcrut4gl/from:1...

Surprised? As you say we're constantly being told that warming 'stopped' or 'ended' 15/16/17/18 years ago.

This persective comes to you most definitely NOT from sceptic blogs and is according to the data too

Variomatic said:

There's a prblem with the warmist insistence on 30+ year trends - apart from the fact that there hasn't been a clear 30 years of warming, and had only been maybe 10 years when they started rining the alarm bells.

Indeed, the alarm bells are based on the science and actually started before ANY warming was observed.

Variomatic said:

IF warming is a continuing linear trend then saying "it's still warming but there's a hiatus" is valid. But that's a very big "if" indeed in a system which we know has had many, many, changes in direction in the past without any help at all from us. And for every year that temperatures remain level (or even start to decrease), the 30 year trend reduces towards zero. We've got over halfway there already, so they really should be admitting to the possibility they're wrong.

The trend has dipped over the last few years but it's too short a period to be drawing conclusions - my money is on a return to warming.

Variomatic said:

plunker said:

A few citations required here.

You'll have to give me a little time on that because, curiously, any mention of such claims doesn't seem to exist anymore except on what you'd dismiss as "sceptic blogs".

More reliable sources such as the MSM seem to have done quite a good job of disappearing any references to such statements. Which is a shame, seeing as that's where my scepticism started LONG before I'd heard of places like WUWT, Climate Depot etc.

In fact, I wasn't all that interested either way except that I noticed that suddenly the BBC was saying that sceptics were wrong because 17 years were needed, when I clearly remembered their last mention where Dr Jones was saying 15 years.

Then 17 years was suddenly a "misrepresentation" of what had been said - according to the very people who'd said it (in that context) in the first place! Around that point I decided that might start digging for myself rather than blindly trusting the meeja and started finding all the other inconsistencies.

Unfortunately, as a dyed-in-the-woll socialist, to do that I found myself having to associate (and be associated with) fairly unsavoury characters like Monkton. But the truth is the truth no matter who's saying it, so i try not to let my own political views get in the way

Anyway, I'll keep digging to see if I can find a forgotten-to-delete "reliable" source for you but, in the meantime, you could try looking for yourself - pretty sure the 15 year claim was by Phil Jones as a satrting point

No probs.

Edited by plunker on Saturday 22 November 11:28