Global Warming

[parmenides3]

This is not a personal comment about BFTP in any way, but you will have noticed that I am dubious about the reliability of some of his sources (see previous posts). The statement that '10 of the 12 columns...very weak' is false. There is concern about the thermohaline circulation because we don't yet know what the consequences of, for example, Arctic melting, will be; the concept of a shutdown is currently being studied, but no conclusive paper has yet been published.

I'm off to bed.

Permanides

No problem re your dubiousness...BUT the slow/shut down of the THC is not my baby! Wrong person

BFTP

Found anything good recently?

[VillagePlank]

Sorry for swaying the topic, but here's my (very) cursory analysis of the last 100 years from the Hadley CET series:

I've left it unannotated, as it requires some explanation, so here were my methods:

(i) Average CET for each year

(ii) SMA (Simple moving average (mag 30) on data from (i)

(iii) % difference of (i) and (ii)

(iv) trendline is a further 30 year SMA of the % difference.

Therefore the vertical axis is the % deviation from the 30 year mean, the y axis is time ascending.

Effectively, the zero base line represents the 30 year average up to (but not including) that year. The bars up and down represent each year's percentage deviation from the 30 year mean. The black line is the 30 year moving average of that difference.

The reason for this method was not to measure magnitude of change, but rather to visualise clusters of cold, and warm periods. It is a 'coincidence' that the black trend line apparently demonstrates global warming. What I find interesting is the cluster to the right which shows a sudden onset of large positive anomalies from the mean, gradually recinding. You should be aware that as the atmopshere warms you would expect the % deviation to rescind on the basis that a warmer atmosphere becomes the 30 year 'norm'

Interesting observation is that there are a high frequency of either positive or negative groups that come in threes; does anyone know of any reasoning that might explain triplet years (or thereabouts) of cold or warm years?

This graph forms no explanation, nor prediction of future events.

The data is available from the MetO website, and my methods are simple, and clear, and the graph is repeatable.

What d'you guys think?

Edited August 7, 2006 by Wilson

[parmenides3]

An interesting way to show the CET anomalies. But:

Effectively, the zero base line represents the 30 year average up to (but not including) that year. The bars up and down represent each year's percentage deviation from the 30 year mean. The black line is the 30 year moving average of that difference.

Doesn't this explain why the positive anomaly recedes over time? What does the CET look like if you use the 1945-1985 mean as your zero baseline (or is that not a characteristic series?)?

[VillagePlank]

An interesting way to show the CET anomalies. But:

Doesn't this explain why the positive anomaly recedes over time? What does the CET look like if you use the 1945-1985 mean as your zero baseline (or is that not a characteristic series?)?

I edited and added that point, I think, while you were writing this post

[Guest Viking141]

Hi Wilson

For the cerebrally challenged among us please explain what your graph means (or could mean)!!

[VillagePlank]

Hi Wilson

For the cerebrally challenged among us please explain what your graph means (or could mean)!!

Each bar represents the percentage difference of that years average temperature when compared to the average of that year's previous 30 years.

The recinding of magnitude of the cluster to the right 'should' mean that the climatic variation of the thirty years before it is now becoming the 30 year mean. Hence, the difference from the last 30 year climatic norm to tend towards zero (which it is, apparently, doing)

The most interesting thing, in my opinion, is the frequency of anomlies that appear in three year clusters. Does anyone have any ideas why this might be the case?

Edited August 7, 2006 by Wilson

[parmenides3]

Wilson, is it possible for you to do a graph of the absolute annual CETs for the past 100 years? :lol:

An interesting point that arises from your graph is the importance of the way in which information is a) calculated and :lol: displayed. Changes in the selection of mean data (and I have constant problems with different websites, where the selected means for the same information is different) make a difference in the way the graph looks. Slight differences in what information is being depicted can also make a lot of difference. A good example here is another of my interests, sea ice. Some graphics show sea ice cover, others show sea ice extent. They sound similar, but one measures the ice taking into account pools and gaps, and the other calculates the total area from the ice edge; not the same.

Presentation is important, too. The choice of scale on graphs can alter the appearance considerably, to such an extent that the 'meaning' of the graph can be deceptive. And this leads to the final point; perception. Many of us (I am one) tend to look at the pretty pictures, but don't always look carefully at what the picture is actually showing. Because there is a strong tendency towards the visual in our perception, we can easily get an impression from a graphic which creates a tendency to assume an 'attitude' to the written information. The point? What we show, and how we show it, especially in relation to matters of climate (this being a weather forum, after all, needs to be carefully considered. this isn't a criticism of you, as I know your graph was just a bit of fun, but it should raise important questions in the mind of anybody looking at climate statistics and trend data.

Please do some more graphs!

:lol:

[Gray-Wolf]

Sorry to be a moaning Minnie but I could have done with the years along the bottom so as to see the impact of things like major eruptions, global dimming/brightning on the series (if any).Is the last year 2005 then?

[VillagePlank]

Wilson, is it possible for you to do a graph of the absolute annual CETs for the past 100 years? :lol:

Yes it is :lol:

this isn't a criticism of you, as I know your graph was just a bit of fun, but it should raise important questions in the mind of anybody looking at climate statistics and trend data.

This was a cursory analysis; I am well aware of the pitfalls of using graphs - see my posts elsewhere :lol:

Please do some more graphs!

I intend to

Sorry to be a moaning Minnie but I could have done with the years along the bottom so as to see the impact of things like major eruptions, global dimming/brightning on the series (if any).Is the last year 2005 then?

I'm working on it, I'm working on it.

Mods; perhaps a new thread for CET graphs?

Edited August 7, 2006 by Wilson

[Devonian]

Sorry for swaying the topic, but here's my (very) cursory analysis of the last 100 years from the Hadley CET series:

I've left it unannotated, as it requires some explanation, so here were my methods:

(i) Average CET for each year

(ii) SMA (Simple moving average (mag 30) on data from (i)

(iii) % difference of (i) and (ii)

(iv) trendline is a further 30 year SMA of the % difference.

Therefore the vertical axis is the % deviation from the 30 year mean, the y axis is time ascending.

Effectively, the zero base line represents the 30 year average up to (but not including) that year. The bars up and down represent each year's percentage deviation from the 30 year mean. The black line is the 30 year moving average of that difference.

The reason for this method was not to measure magnitude of change, but rather to visualise clusters of cold, and warm periods. It is a 'coincidence' that the black trend line apparently demonstrates global warming. What I find interesting is the cluster to the right which shows a sudden onset of large positive anomalies from the mean, gradually recinding. You should be aware that as the atmopshere warms you would expect the % deviation to rescind on the basis that a warmer atmosphere becomes the 30 year 'norm'

Interesting observation is that there are a high frequency of either positive or negative groups that come in threes; does anyone know of any reasoning that might explain triplet years (or thereabouts) of cold or warm years?

This graph forms no explanation, nor prediction of future events.

The data is available from the MetO website, and my methods are simple, and clear, and the graph is repeatable.

What d'you guys think?

Wilson, I'm going to think aloud about you're graph.

First thought, that average depature from anomaly doesn't appear to have changed. But, since the average has risen then compring a year now with a year in the past with a lower CET using rolling CET is a bit odd since a year now would (rightly imo) appear warmer (it is) if compared with a 30 year mean from somewhere the past. So your graph has removed the warming trend from the CET and instead is compaing 'devationness' from the current mean. I'm not sure what that actually tells us, other than deviations form current means don't apeared to have changed much.

[VillagePlank]

Wilson, I'm going to think aloud about you're graph.

First thought, that average depature from anomaly doesn't appear to have changed. But, since the average has risen then compring a year now with a year in the past with a lower CET using rolling CET is a bit odd since a year now would (rightly imo) appear warmer (it is) if compared with a 30 year mean from somewhere the past. So your graph has removed the warming trend from the CET and instead is compaing 'devationness' from the current mean. I'm not sure what that actually tells us, other than deviations form current means don't apeared to have changed much.

No problems. This graph, as I've said before, is simply a cursory analysis. There are mistakes in the graph (mathematical ones) which I will correct fairly shortly.

You are incorrect in your analysis, though, mainly because you arrive at the table with a presumption. I can forgive that: but just this once . . . :lol:

[parmenides3]

Important notice for the record.

Re-reading my previous post, it could be interpreted as a commentary on Wilson's graph. If you read it as so, please erase this thought from your memory. Wilson's graph is a perfectly legitimate way of displaying the information. The thrust of my comment was intended to alert readers to the dangers of believing what they see without question.

My apologies to you, Wilson, for any misunderstanding. :lol:

By the way, I've no idea whatsoever why there are several triplets', unless its a function of the formula, but I can't work ourt how that could be the case either.

:lol:

[Gray-Wolf]

Things always come in 3's? ........It actually makes me dizzy just trying to best understand what we are not only trying to measure but also to explain. For example the temperature averages are just that, average temps for a year.But what brought in that average? Dominant H.P.'s over winter allowing increased night-time radiation and lower mins or H.P.'s dominant through the summer months leading to heatwaves? Dominant zonality?(or a mixture of both to bring a 'null') in effect it is a narrow 'slice' of the 'temperature' story but it could highlight some interesting quirks of nature .So why would/could there be a 3 year temp. trend anomally that looks so pronounced but hasn't been highlighted before?Almost like we had a 'long year' imprinted over the solar years. What could cause that then?

[parmenides3]

Things always come in 3's? ........It actually makes me dizzy just trying to best understand what we are not only trying to measure but also to explain. For example the temperature averages are just that, average temps for a year.But what brought in that average? Dominant H.P.'s over winter allowing increased night-time radiation and lower mins or H.P.'s dominant through the summer months leading to heatwaves? Dominant zonality?(or a mixture of both to bring a 'null') in effect it is a narrow 'slice' of the 'temperature' story but it could highlight some interesting quirks of nature .So why would/could there be a 3 year temp. trend anomally that looks so pronounced but hasn't been highlighted before?Almost like we had a 'long year' imprinted over the solar years. What could cause that then?

It might take a while to look into this, so, while you're waiting, I thought I'd throw a spanner in the works. :o

Here, I've copied the 'manifesto' of a GW 'nonconformist'. I hope he doesn't mind me using the term, likewise, I hope he doesn't mind me posting the material. There's a lot to get your teeth into here; the website is worth a visit.

Note how carefully each of the statements is phrased.

Main Conclusions

The Climate Science Weblog has clearly documented the following conclusions:

The needed focus for the study of climate change and variability is on the regional and local scales. Global and zonally-averaged climate metrics would only be important to the extent that they provide useful information on these space scales.

Global and zonally-averaged surface temperature trend assessments, besides having major difficulties in terms of how this metric is diagnosed and analyzed, do not provide significant information on climate change and variability on the regional and local scales.

Global warming is not equivalent to climate change. Significant, societally important climate change, due to both natural- and human- climate forcings, can occur without any global warming or cooling.

The spatial pattern of ocean heat content change is the appropriate metric to assess climate system heat changes including global warming.

In terms of climate change and variability on the regional and local scale, the IPCC Reports, the CCSP Report on surface and tropospheric temperature trends, and the U.S. National Assessment have overstated the role of the radiative effect of the anthropogenic increase of CO2 relative to the role of the diversity of other human climate climate forcing on global warming, and more generally, on climate variability and change.

Global and regional climate models have not demonstrated skill at predicting climate change and variability on multi-decadal time scales.

Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.

A vulnerability paradigm, focused on regional and local societal and environmental resources of importance, is a more inclusive, useful, and scientifically robust framework to interact with policymakers, than is the focus on global multi-decadal climate predictions which are downscaled to the regional and local scales. The vulnerability paradigm permits the evaluation of the entire spectrum of risks associated with different social and environmental threats, including climate variability and change.

Humans are significantly altering the global climate, but in a variety of diverse ways beyond the radiative effect of carbon dioxide. The IPCC assessments have been too conservative in recognizing the importance of these human climate forcings as they alter regional and global climate. These assessments have also not communicated the inability of the models to accurately forecast the spread of possibilities of future climate. The forecasts, therefore, do not provide any skill in quantifying the impact of different mitigation strategies on the actual climate response that would occur.

Weblog editors: Dallas Staley and Sloan Johnson

Material courtesy of Climate Science http://climatesci.atmos.colostate.edu/

The intention of this post is not to proselytise, or even imply agreement with, or support for the authors, merely to open up the GW debate to some more lively discussion.

Enjoy.

[Devonian]

No problems. This graph, as I've said before, is simply a cursory analysis. There are mistakes in the graph (mathematical ones) which I will correct fairly shortly.

You are incorrect in your analysis, though, mainly because you arrive at the table with a presumption. I can forgive that: but just this once . . . :o

You better explain which analysis, and what presumption, else I'll think it's you with the presumption

[VillagePlank]

Two more graphs for you guys to muse over.

Edited August 8, 2006 by Wilson

[VillagePlank]

You better explain which analysis, and what presumption, else I'll think it's you with the presumption

The presumption of incessant warming, of course. Read your parenthesised comments. You might indeed be correct, but as we're trying to start from first principles here (as much as we can - I can't get hold of weather station data without paying) so any presumption of warmth is summarily excluded :o

[Gray-Wolf]

The 'trend' that initially leaps out at me has to be the 2 'warming phases' (1902-1950 & 1992 to present) and the fact that 1 period of 0.5c rise took 50 yrs and one took 10yrs. Had the global dimming of the 40's,50's , 60's and 70's not intervened I feel we would not be engaging in such debates as this in 2006 but more of the 'where do we go from here' type conflab.

[VillagePlank]

Yes, GW, I agree. It is the rate of change rather than the magnitude of change that looks alarming, here. I'll have to do the whole series I have from c1700 to see if there has been any other period with the same rate of change.

There is a peculiar cooling period between 1960 and 1990, though (cool years against their 30 year mean, that is) which hints that 1930-1960 was a period of climatic cooling, not warming.

Has anyone got any ideas for a rolling CET mean. I chose 30 years because that's what everyone else seems to agree is a reasonable measure of climate; should we be looking at smaller cycles, or larger ones, for instance?

Edited August 8, 2006 by Wilson

[Devonian]

The presumption of incessant warming, of course. Read your parenthesised comments. You might indeed be correct, but as we're trying to start from first principles here (as much as we can - I can't get hold of weather station data without paying) so any presumption of warmth is summarily excluded

No I did not say that. I said 'it is' not 'it will' or (most certainly) 'incessantly' - Flippin' heck...

It is warming - end, period, finito (as in, to deduce it is warming you need a measure of time and over a reasonable measure of time it clearly IS warming (CET, globally, more or less where ever or whatever)) I take your comments in good faith and then I find you are misrepresenting me :o . I will say that if the running mean temps level off you could say what you did. That is not impossible, but seems unlikely given NH warmth this year.

Still, I see you don't dispute my reasoning So the graph does only show 'deviationess' from the current mean? I (sincerely) actually fail to see what that tells us ?

Thus, what does 'deviationess' from the current mean petrol price tell us about the real cost of petrol, it's relative cost??? Nowt. To know the reason why the rise in petrol prices has had little effect you need to know that, in real terms, it's still cheap.

[Gray-Wolf]

Thus, what does 'deviationess' from the current mean petrol price tell us about the real cost of petrol, it's relative cost??? Nowt. To know the reason why the rise in petrol prices has had little effect you need to know that, in real terms, it's still cheap.

Now that would depend on what you wanted wouldn't it? If it was a measure against inflation (whether it kept up with inflation or whether fiscal considerations were more important in it's pricing etc.) If you saw a pattern in prices which mean't that every 6 years you could make a killing you would also say it showed a lot. The rate of change away from the mean enables some climate functions to be highlighted (flip flops of positive/negative anomalies) and some of the 'changes' more visible. As I had posted earlier the measure is limited but can be used to investigate other influences on our climate further (the cool off after Pinatubo in the early 90's and eventual re-warm for instance).Apart from anything else it also provides us with a topic to maul!

EDIT it also makes you wonder whether we'd have made the 0.5c rise in the 10yrs had Pinatubo not blown its top!

Edited August 8, 2006 by Gray-Wolf

[VillagePlank]

It is warming - end, period, finito (as in, to deduce it is warming you need a measure of time and over a reasonable measure of time it clearly IS warming (CET, globally, more or less where ever or whatever)) I take your comments in good faith and then I find you are misrepresenting me . I will say that if the running mean temps level off you could say what you did. That is not impossible, but seems unlikely given NH warmth this year.

The running mean difference is tending towards zero in the last few years, and this supports your case of a warmer climate, not a cooler one.

I (sincerely) actually fail to see what that tells us ?

It tells us exactly what it says on the tin, doesn't it?

Thus, what does 'deviationess' from the current mean petrol price tell us about the real cost of petrol, it's relative cost??? Nowt. To know the reason why the rise in petrol prices has had little effect you need to know that, in real terms, it's still cheap.

I suggest you take that up with all of the major climate centres who regularly represent their data as differences against all sorts of averages. The hockey stick graph, whether you accept its findings or otherwise, is one such graph. :o Edited August 8, 2006 by Wilson

[Guest Viking141]

It might take a while to look into this, so, while you're waiting, I thought I'd throw a spanner in the works. :o

Here, I've copied the 'manifesto' of a GW 'nonconformist'. I hope he doesn't mind me using the term, likewise, I hope he doesn't mind me posting the material. There's a lot to get your teeth into here; the website is worth a visit.

Note how carefully each of the statements is phrased.

Material courtesy of Climate Science http://climatesci.atmos.colostate.edu/

The intention of this post is not to proselytise, or even imply agreement with, or support for the authors, merely to open up the GW debate to some more lively discussion.

Enjoy.

Thanyou Parmenides, I did enjoy. A lot in there that I agree with. The most telling point I think was the very last paragraph

"Humans are significantly altering the global climate, but in a variety of diverse ways beyond the radiative effect of carbon dioxide. The IPCC assessments have been too conservative in recognizing the importance of these human climate forcings as they alter regional and global climate. These assessments have also not communicated the inability of the models to accurately forecast the spread of possibilities of future climate. The forecasts, therefore, do not provide any skill in quantifying the impact of different mitigation strategies on the actual climate response that would occur."

Spot on as far as Im concerned regarding the fixation on CO2, the impact of human climate forcings and for me the absolutely key phrase "not communicated the inability of the models to accurately forecast the spread of possibilities of future climate" quite so.

[parmenides3]

EDIT it also makes you wonder whether we'd have made the 0.5c rise in the 10yrs had Pinatubo not blown its top!

Don't you mean it makes you wonder what the rise would have been if Pinatubo had not had a dampening effect?

I'm going to change the subject a bit. Not that the discussions of Wilson's graphs isn't interesting, but I've spent much of the past twelve hours looking at an important site which was new to me: The Arctic system in a Changing World; Second International Conference on Arctic Research Planning. You can find it on http://www.icarp.dk/

Particularly relevant to a discussion of GW is the material from Working group 9; modelling and predicting Arctic weather and climate.

The conference took place last November and the proceedings were published this year, so its about as up-to-date as we can hope for.

There are discussions about the NAO/AO and PNA, the thermohaline circulation, natural vs. anthropogenic forcings. The focus is on first order feedback and forcing mechanisms over the coming 100 years. Much of this relates directly to discussions of GW scenarios and GCMs.

I hate to admit it, but it demonstrates that, in my case at least, a little knowledge is a dangerous thing. I am now less sure about several of the observations I have made here about thermohaline circulation shutoff in particular, and more aware of the plausibilty of a rapid 'switch' in conditions. It is a bit dry in parts, but worth persevering with.

Back to the subject of graphs: what strikes me about all of Wison's graphs is that the measured temperature upturn is still clearly visible in all of them. Another possible inference that could be made is that there is some degree of recent stabilisation in the rate of acceleration of warming (I think that's right). Having tried to make my own graphic (with pathetic results) has made me more aware of his sterling efforts in the cause.

Indeed, Viking! Is it possible that the political (and media) concentration on CO2 is a deliberate over-simplification with a cynical, manipulative agenda?

I'm not sure it's entirely fair to blame the IPCC for this fixation, though.

:o

Edited August 8, 2006 by parmenides3

[Devonian]

I suggest you take that up with all of the major climate centres who regularly represent their data as differences against all sorts of averages. The hockey stick graph, whether you accept its findings or otherwise, is one such graph. B)

But, the 'hockey stick' doesn't compare aginst running 30 year means, indeed I can't think of any graph anywhere that does? Not against running means? I just think comparing aginst running mean adds confusion (I'm certainly getting confused ), because you're not comparing years to the same base line. So to me it's rather (though I take GW's point about inflation) rather like comparing present petrol prices with the mean of the present and past petrol proces with the mean of the past. To get at real petrol prices excluding inflation you exclued infalation and measure against a base. Likewise with temperature if you want to get a warming due to one factor you exclude uhi, and the rest and measure against a baseline.

So, I still don't really get what this graph shows that's helpful?