Last August I posted a comment at this blog titled ‘The Troposphere is Warming’, in which I explained that, in accordance with global warming models, and according to a series of papers in the journal Science, the lower troposphere was warming.
Yesterday Vincent Grey sent me the following graph from the oh-so-not confidential IPCC report on the physical basis for global warming, as reviewed in a recent volume of Nature but not to be published until February next year, click here for a background briefing.
Vincent Grey interpretes this graph as showing no evidence of warming. As posted yesterday he has commented that:
“The satellite measurements show no temperature change between 1979 and 1997, but is then followed by a large sharp peak in 1998 because of the El Nino ocean event of that year, and since 2001 has shown a modest warm spell.”
What is also interesting is that the two cool periods follow volcanic activity – El Chichon in 1982 and Pinatubo in 1991.
I wonder if any volcanos are likely to erupt in the next few years?
I find the graph fascinating.
It doesn’t suggest to me a really close correlation between atmospheric carbon dioxide levels that have been showing a consistent rising trend over this time period, and the temperature in the lower troposphere?
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
And even if there was a “correlation” – it does not imply “causation”. It is a complex mess, this whole climate modelling business. At this point I am still up in the air about exactly what is happening and how much is really man-made.
However, to hedge my bets – I am offsetting carbon emissions over at CarbonFund.org (an non-profit). In fact, if you or your readers link back to my blog I will offset one ton of carbon emissions.
By the way – volcanos emit about 200 million tons of carbon a year vs. about 24 billion tons by man. I am still not convinced that is the whole picture, but part of the puzzle…
I don’t quite understand “offsets” as emissions are near 1:1 corellated with wealth. The big ole nasty US is “responsible” for 24% of emissions and 22% of wealth for but one obvious instance. “Buying back” is the same as wealth redistribution is it not?
jennifer, here is a better rendering from your illustration
http://www.john-daly.com/nasa.gif
Re Eric’s comment about volcanoes.
Its not the volcano CO2 but the particulates and albedo effects thats more relevant I’d suggest.
Maybe thats what Eric is driving at though.
Points of note:
1. Until recently, the satellite data was used by most skeptics (including other members of the IPA*) as proof that global warming wasn’t occurring. Now that the data has been corrected after vigorous debate, and we have more data due to the passing of time, the data show warming that is consistent with climate models, and yet it has suddenly become problematic, and is another source of proof to be attacked.
I agree that this short temperature trend ALONE is not sufficient to conclude that the globe is warming, but I think the whole process highlights the poor intellectual form of those who had previously used this small, hotly debated data set as proof that global warming was not occurring.
2. The longer temperature trend from surface measurements shows warming over a longer period.
* I have read a few times where Alan Moran has referred to the satellite data as ‘the only reliable record’ of global temperatures. I wonder if he still feels this way?
http://onlineopinion.com.au/view.asp?article=1907
Jennifer – apart from the ethical considerations that Mr Grey seems to feel that he is released from this is a prime example of cherry-picking.
This report is embargoed from publication despite what the US government has done. When you get your password I assume that you agree to the terms that the password is issued under. The fact that someone else breaks that rule is NO opening of the floodgates releasing you from the obligation that you signed up for. I am absolutely sure that you would be really annoyed and calling for lawyers if a book or publication that you had written was pre-released before you approved it. I would ask you to stop publishing bits of the report in isolation until the whole report is released.
Anyway the problem is that this is one dataset of the whole evidence for global warming. The MSU satellites are 30 years old and the instruments were not originally designed for the measurements that they are doing now. The fact that they show any warming at all is an indication that there is something happening. Higher resolution satellites are needed with instruments that are tailored for measuring the upper troposphere.
The current warming shown by these satelites are in line with modelling and consistant with the vast amounts of other data that support AGW.
This is pretty much the definition of cherry picking, seizing on one of many empirical observations trying hard to support a pre-conceived conclusion.
If you wish to disregard the satellite records, the following diverse and numerous empirical observations also lead us to the unequivocal conclusion that the earth is warming:
CRU temperature trend:
http://www.cru.uea.ac.uk/cru/info/warming/
NASA GISS temperature trend:
http://data.giss.nasa.gov/gistemp/
Radiosondes:
http://cdiac.esd.ornl.gov/trends/temp/angell/angell.html
Borehole analysis:
http://www.ncdc.noaa.gov/paleo/globalwarming/pollack.html
Glacial melt observations:
http://nsidc.org/sotc/glacier_balance.html
http://www.realclimate.org/index.php?p=129
Sea ice melt:
http://nsidc.org/news/press/20050928_trendscontinue.html
Sea level rise:
http://sealevel.colorado.edu/
Proxy Reconstructions:
http://www.ncdc.noaa.gov/paleo/globalwarming/paleolast.html
Permafrost thawing:
http://www.newscientist.com/channel/earth/mg18725124.500
All of these completely independent analyses of widely varied aspects of the climate system lead to the same conclusion: the Earth is undergoing a rapid and large warming trend.
Ender, Cody,
On cherry picking:
1. A blog, by its very nature, is about picking bits of information – often the most interesting which often involves cherry picking. In contrast, if I was writing a book I might be expected to deal with all issues at once?
2. I acknowledge that there is warming. I’m particularly interested in the relative contribution of greenhouse gases. And I would have thought that if these gases were the significant factor then this might be evident by more significant warming in the troposhere relative to say at the Arctic?
coby,
but is the warming unprecedented?
Europe in the last 2 centuries:
http://home.casema.nl/errenwijlens/co2/centraleuropetempupd.gif
The climate of holland in the last 3 centuries:
http://home.casema.nl/errenwijlens/co2/labrijnkoeppen.gif
the alpine Aletsh glacier in the last 2000 years:
http://www.klimanotizen.de/assets/images/2003.10.25_aletschgletscher_2000_1.gif
sorry, all waffle
Hi Jennifer,
(The name is “Coby” btw, not Cody.)
Cherry picking is a kind of deception so I do not agree that it is in the nature of a blog. Yes, we all point out things we find interesting, but hopefully not all of us do it with the intention to mislead.
I’m happy you accept that there is warming, forgive me if I can’t always tell given the information and commentary you chose to highlight.
AFAIUI, polar amplification in the arctic is in line with predictions and the troposphere is expected to warm only slightly more than the surface, also according to theory. The tropospheric observations remain inconclusive due to the short time they have been available. I think the fairest characterization is that we have enough data to conclude there is no apparent contradiction but not really enough to say there is very good agreement. The very hot off the press USCCSP report has concluded:
“there is no longer a discrepancy in the rate
of global average temperature increase for the
surface compared with higher levels in the
atmosphere. This discrepancy had previously been
used to challenge the validity of climate models
used to detect and attribute the causes of
observed climate change. This is an important
revision to and update of the conclusions of
earlier reports from the U.S. National Research
Council and the Intergovernmental Panel on
Climate Change”
http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm
In terms of the “is there, isn’t there” AGW debate the only interesting thing about the satellite readings is the lengths some people (Vincent Gray obviously included) will go to to spin it into agreement with non-scientific preconceptions.
The Earth’s variable climate has certainly warmed up since the LIA, otherwise we would still be in the LIA, although we are still within the bounds of normal variability for the Holocene. There isn’t a good correlation with CO2. Roger Pielke Senior has recently calculated the fraction of ‘global warming’ that is due to the radiative forcing of increased atmospheric CO2, with generous use of the IPCC perspective on climate forcings. The result is 26.5%
http://climatesci.atmos.colostate.edu/2006/04/27/what-fraction-of-global-warming-is-due-to-the-radiative-forcing-of-increased-atmospheric-concentrations-of-co2/
About half the estimated 0.6C rise occurred before any significant increase in CO2. 26.5% of 0.3C is 0.08C.
I think Shaviv and Veizer have the answer to two-thirds of the cause of climate change – Cosmic Ray Flux modulated by solar wind and the 11-year solar cycle:
Brighter sun – enhanced thermal flux + solar wind – muted cosmic ray flux – less low-level clouds – less albedo – warmer climate.
There is even evidence from ‘cloud chamber’ experiments.
Coby,
Your great at quoting what the expert or institution has concluded …and this can provide interesting and useful information.
In contrast, Vincent Grey seems to like to make up his own mind, provide his own interpretation based on his own prejudices.
I would be really interested to know what you, as an individual with some knowledge of climate change, think about the above graph.
What does it say to you?
This is in answer to your comment on the Pell thread, Jennifer.
I am sure that Coby feels compelled to quote authoritative sources as an antidote to people lazily quoting uninformed sources. Perhaps if he makes it easy for us to get good information we will read it even if it is more arduous than quoting the latest science fantasy masquerading as fact.
As you say to Coby, may I say to you: “I would be really interested to know what you, as an individual (after you have better) knowledge of climate change (by reading material such as Coby persistently points you to), think about the above graph.”
If you want easier reading, RealClimate has recently reviewed three books: Eugene Linden’s The Winds of Change, Elizabeth Kolbert’s Field Notes from a Catastrophe and Tim Flannery’s The Weather Makers. I personally haven’t got round to reading them yet as I have time to get my information from the horse’s mouth.
Understanding global warming is a bit like identifying the eucalypts, you can’t just take one feature and jump to conclusions. As an Australian with a professed interest in our water supply I would think that a more holistic knowledge of this subject would be useful to you.
Hans,
Yes, the warming is likely unprecedented in the Holocene period very likely unprecedented in the last 2000 years. You have to distinguish between between regional climate change and the global one we are in the midst of.
Please have a look at NOAA’s paleoclimate pages:
http://www.ncdc.noaa.gov/paleo/paleo.html
It is a big mistake to look at european history and extrapolate global trends from that. The studies you can find in the above link are global and state of the art, it is the best knowledge of past climate that we have at the moment.
Jennifer,
I agree with your characterization of what Vincent Grey does. It is a difficult thing to carefully remove one’s prejudices from ones conclusions, even in science it is perhaps ultimately impossible to do so completely except for the most trivial of empirical observations. I suppose we can’t fault Grey too much for not even trying.
What the graph above says to me is that in one particular analysis of satellite microwave data, the troposphere is showing a warming of around .3oC over the 27 year length of its record. It looks like warming is more pronounced in the latter part. The record is too short to be definitive. It seems to confirm very nicely the expected cooling effect from Pinatubo and it shows a very pronounced El Nino signal.
Personally, knowing a little about how hard it is to determine this temperature trend from the actual data and the history of errors that have plagued it, I am not very interested in this line of GW evidence. Now that the models have proved more reliable than these measurements several times in a row and considering the complexity involved, I think this record will simply be analysed and corrected and reworked until it agrees very well with the model predictions and then people will stop examining it. We will not know if all the errors have been found though.
Better ways to measure tropospheric temperature may be found or may be underway at the moment, but we will be back to year one with no reliable trend for decades to come. I prefer to look at all the other more reliable evidence such as I offered above.
Coby
I haven’t noticed Vincent to show any more or less prejudice than you.
What I have observed is that some people see the glass half full, others see it half empty and some people search for what fits an accepted pattern, while others notice what doesn’t match.
The one’s that see what doesn’t match can be very useful.
At school I was sometimes accused of being a “trouble maker” because I could see what didn’t fit the explaination from the teacher. I wasn’t trying to make trouble when I pointed out such inconveniences … I was simply wanting to understand why.
Jennifer – a “bad” girl eh?
Now it all makes sense…….
Ian K,
I am surprised you accuse me of not reading the blog Real Climate … I do. And I’ve already read Gavin’s review of the three books. And I’ve already read Flannery’s book ‘The Weather Makers’. If you do a search at this blog you’ll probably find some reference to it.
You really do jump very quickly to wrong conclusions about what I do, and do not know, and do and do not read?
Jim,
Now you’ve reminded me of grade 8 and those false accusations.
It is interesting how different cultures at different organisations and institutions deal with ‘curiosity’.
Interestingly I never found university as ‘open minded’ as I thought it would be. Think tanks tend to love new ideas and an argument in pursuit of knowledge … so I feel quite at home at the IPA.
At UQ (’82 – ,84 and again in ’86) I found very little intellectual freedom or genuinely open debate.
Orientation Week seemed more designed to shock than inform.
The Rec Club was the place I enjoyed the most!!
Please. Poor show Jennifer. I was considered a troublemaker too for some teachers at least. I always questioned what I was told both when it came to school rules and academics. Save the back handed ad hominems and instead address the arguments and support your points with evidence, not concuring opinions.
To date you have not done so, so I reject your accusations about my objectivity as the distraction they are.
Now Coby, you are often suggesting I have some hidden motive for picking the information that I choose to post. I’m just explaining … that I’m curious by nature, not trying to be deceptive as you suggested in a comment above and at other threads.
This post is about a graph – a rather fascinating graph in my opinion.
And I quoted Vincent Grey as he seemed to do a reasonable job of describing it. … I went on to comment that I would have expected a better correlation with CO2 levels given the presumed importance of the troposphere, and in particular greenhouse gases in the troposhere, as a driver of warming. That’s about it.
I don’t think your description was as good as Vincents … you wandered from the evidence at hand.
I wonder what others think of what Vincent describes as the “modest warm spell”?
Jennifer – “I went on to comment that I would have expected a better correlation with CO2 levels given the presumed importance of the troposphere, and in particular greenhouse gases in the troposhere, as a driver of warming”
The troposhere extends from the surface to to roughly 17km –
http://www.globalchange.umich.edu/globalchange2/current/lectures/ozone_deplete/ozone_deplete.html
“The troposphere is the lowest layer of the atmosphere, extending from the ground to roughly 10 – 17 km altitude. The vertical extent of the troposphere varies with latitude and season. With the most intense heating (and subsequent convection) occurring at the Earth’s equator year-round, it is not unusual to find the troposphere extending to ~ 17 km. Near the winter pole, the air is cold and dense and the troposphere may only extend to 9 or 10 km. The temperature in the troposphere decreases with height. That is, as you go higher in altitude, the temperature decreases. If you consider an air parcel that rises in the troposphere, it encounter air parcels having temperatures colder that itself. Since hot air (less dense air) rises, it will continue to rise. The troposphere is a zone of rapid vertical mixing in addition to horizontal winds.”
The surface temperature records which extend for 100 years or more shows significant warming so the troposphere at the lowest level is warming. As both Coby and Gavin have explained in posts to this blog there is a lag in atmospheric heating due to the heatsink effect of the oceans. The 30 year record of the troposhere at a higher level is showing warming. However as I said before the instruments that record this temperature are not ideal for this sort of measurement and there could be signficant warming that we are not seeing.
Thanks Ender.
So what do you make of the “modest warm spell”?
The ‘pattern’ seems to have changed post 1998?
Jennifer,
Discerning a trend out of noisy data requires smoothing. When you do this smoothing in the surface record it thereby greatly reduces the anomalous high of 1998. This record hot year was a full .2oC above the actual trend.
When you do this smoothing you clearly see that there has been no cessation of warming whatsoever.
Have a look at this graph from NASA GISS:
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2_lrg.gif
The red line represents five year averaged smoothing, ie each point is an average of 2 years previous to two year following. We will not actually know where the trend is in 2005 until 2007. Anyone with a science background who ever tries to draw a conclusion about climate much less climate trends by drawing a straight line from one anomalous high or low year to any other point is trying to fool you (ie Bob “warming stopped in 1998” Carter).
Likewise, trying to prove a point with the satellite record alone, ignoring all other evidence is incorrect and if it is coming from an educated scientist, it is a deception.
Why do recommend the data be smoothed? Why is it appropriate here? And sometimes to understand the potential contribution of a single component … it is necessary to disregard the overall pattern.
Jennifer – “So what do you make of the “modest warm spell”?
The ‘pattern’ seems to have changed post 1998?”
No the pattern is pretty consistant. 1998 was a el- nino year. Warming recently is without this effect. The slight cooling observed still leaves temperatures higher that before.
Just eyeballing the whole chart, there’s probably a very slight uptrend. 1998 was obviously a standout. Not sure why 2005 isn’t higher, wasn’t it supposed to be a very hot year? Probably the data needs “calibrating”.
The trend since 2001 looks pretty flat. Of course the correlation with atmospheric CO2 doesn’t exactly smack you in the eye.
Although we won’t know where the trend of the GISS numbers is in 2005 until the December 2007 average has been posted, it is possible to say now that it is unlikely that the 5-year moving average centred on 2005 will be as high as the monthly average for 2005.
The monthly average for the first 4 months of 2006 averaged 0.53 deg. C, which was below the corresponding averages in each of the preceding four years, and was 0.19 deg. C below the highest monthly temperature anomaly during the period (0.72 deg. C).
For the 5-year moving average centred on 2005 to reach the 2005 average level, it would now be necessary for the next 20 monthly averages to exceed 0.76 deg. C. Given the considerable variability in the monthly series, this would be a rather surprising outcome.
In my opinion, the 5-year moving average is rather a crude procedure for this series. While the calculating of a trend is necessary to avoid giving excessive weight to the latest monthly figure, it is an overcorrection to give the most recent monthly averages no more weight than the averages five years earlier.
The more technically correct procedure, I think, is to give the highest weight to the latest monthly average, somewhat less to the previous month and so on, tapering back to a nil weight over a period of five years (or perhaps more).
There is a tension between, on the one hand, quickly picking up changes in trend and, on the other, avoiding the ‘predicting 7 of the last 3 recessions’ syndrome. So the weight to be given to the latest month, and the rate and period of taper, should be determined by statisticians after examination of the characteristics of the series.
The movement of a 5-year moving average from one month to the next depends upon both the latest month’s average and the monthly average 5 years ago that ‘dropped out’ of the calculation. This introduces an arbitrary element which can be avoided by using a tapering formula (because when (say) May 2001 drops out of the average of 5 years ending in May 2006, it would already have had a minuscule weight and so the final dropping out has a imperceptible effect on the series).
Thanks Ian. So what do you think? Was there a change in the ‘pattern’ after the spike?
I think it was perhaps premature of Vincent to describe the last few years as a “modest warm spell”. How would you describe the graph as it is posted above?
I’m just curious to read your thoughts. …and also Cathy’s, if she is out there.
Coby could reasonably ask why I’ve focused so closely on the short-term temperature trend when I’ve argued on another thread that the focus of climate policy in the coming decades should be on enhancing human welfare, especially in developing countries. Let me try and explain.
According to a paper in the conference volume from which I quoted in the earlier discussion, ‘James Hansen et al’ estimated in 1986 that the potential rate of warming that might result from increased GHG concentrations in the rest of the TWENTIETH CENTURY – i.e., within a period of ~15 years – was a 1 deg. C (1.8 deg F) increase in global temperature (‘The Greenhouse Effect: Projections of Global Climate Change’, in ‘Effects of Changes in Stratospheric Ozone and Global Climate’, J G Titus ed., US EPA and UNEP, Washington, DC., August 1986: cited in Kenneth P Linder and Michael J Gibbs, ‘The Potential Impacts of Climate Change on Electric Utilities: Project Summary’ in the October 1987 conference volume I’ve already referenced). The EPA/UNEP volume is not available online or in any library to which I have access, so I’ve been unable to confirm that Dr. Hansen has been correctly quoted.
Anyway the point I want to make is that IF the temperature had been increasing at the rate of 0.7 deg C/decade since the mid-1980s, as apparently estimated by Hansen in 1986, rather than at the rate of 0.15 deg C/decade which Hansen et al (2005) cite as the observed rate of mean temperature increase in recent decades, the decisive upward trend would be much more apparent in the GISS monthly temperature series. For example, it would be expected that the mean temperature in the most recent year in a 5-year moving average would be 0.3 deg. C higher than the first year in that average. With such a trend, the probability of four successive months having a lower average temperature than the corresponding four months in EACH of the previous four years would be virtually nil.
Coby characterised my position as meaning ‘that if we accumulate enough wealth we will be able to deal with very severe climate change’, but this isn’t my position at all. I am arguing that, if climate science is right and if projections of climate change are based on realistic projections of emissions rather than the fanciful IPCC storylines, climate change will NOT be ‘very severe’. Hansen et al (2005) project that the temperature change in the 21st century under the B1 scenario (which I believe to be on the high side) the increase in temperature by 2100 will be 1.1 deg. C (much of which Hansen et al estimate will occur anyway, whatever happens to emissions). If temperature had increased by 1.0 deg C in the last decade-and-a-half of the twentieth century and was projected on reasonable assumptions to continue to increase at this rate or even higher, I’d be the first to agree on the seriousness of the climate change problem and the need for a different balance in the response as between adaptation and mitigation to that implied in my prescription.
Jennifer please forgive this long and tardy response: this seems a busy thread. I apologise if I have picked up an erroneous impression of you from the few threads I have read on your blog ( I am a slow reader is my only excuse). I stand corrected. My original reference to “sloth” was only meant to apply to the Pell thread. It seemed so beautifully morally anachronistic that I couldn’t resist using it in that context. Then when I read this thread where you seemed to be chiding Coby for quoting authoritative documents, in contrast to your quoting Michael Crichton I just couldn’t help myself. Looking around a bit I can see that he IS rather prolific and tends to rush in a bit. I forgive him, I suppose, because from my point of view his heart is in the right place.
If you are up on the subject Jennifer as you infer, I would appreciate any counterview you may have to the following.
I really do not put much weight upon this graph of what seems such noisy data from an unreliable source. I think you have said before that one right scientist can trump a hundred who are wrong. To me one or two facts about climate science cut through thickets of graphs and trump noisy data and sophisticated interpretation thereof.
As far as I am aware, laboratory experiments over a long period have clearly established that CO2 absorbs infrared radiation. If this is the case (and I am aware, at least in general terms, of the saturation of absorption lines, their smearing with temperature and pressure, logarithmic falloff, etc.) then how can it not play this role in the atmosphere as well? It also seems obvious to me that rising temperatures due to CO2 increases will lead to positive water vapour feedback effects.
Now it also seems commonsense to me that negative feedback effects such as convection, cloud formation, etc cannot completely counteract the effects of the increases of these two gases in the atmosphere. As, unfortunately, I hold these facts to be obvious I would appreciate any views that you may have to counteract them. Believe you me I find a belief in global warming burdensome and a pain in the butt!
One outcome of global warming could be dramatic cooling of Britain and northern Europe.
Scientists now have evidence that changes are occuring in the Gulf Stream, the warm and powerful Ocean current that tempers the western European climate.
Ice melting in Greenland could cause a weakening of the Gulf Stream, which means less heat is reaching northern Europe.
http://edition.cnn.com/2005/TECH/science/05/10/gulfstream/index.html
Ian K,
Just because I quote Crichton or Pell or Grey doesn’t mean I subscribe to their view. But does usually mean that I consider their view interesting or noteworthy.
Now you espouse a generally accepted theory above, and I shall accept it. But tell me, what do you think of the above graph in the context of this theory?
Ian K, Your analysis seems correct to me. It is in line with Garth Paltridge’s statement that:
‘Whatever is the total feedback factor in the real world, the temperature change is always going to be positive. In this restricted sense the bald statement that ‘the science of greenhouse warming is proven’ is indeed acceptable. Increasing CO2 will almost certainly lead to higher temperatures. What is NOT acceptable is the corollary implied by those who loudly use the statement in public – namely, that the rise in temperature will be so large as to be disastrous (or even so large as to be noticeable!).”
Now that Gavin has said on RC that there is no difficulty calculating the feedbacks in each of the models used by the IPCC, I don’t understand why someone doesn’t just do it.
What you’ve said is also completely in line with Richard Lindzen’s position, as stated in his written submission to the Lords Committee:
“… few would fundamentally disagree with the following:
“2. CO2 is a greenhouse gas and its increase should contribute to warming.
“3. There is good evidence that man has been responsible for the recent increase in CO2 …”
Lindzen refers to these propositions (and some others) as the ‘basic agreement’, and says that ‘To this extent, and no further, it is legitimate to speak of a scientific consensus.’
From the standpoint of what the policy response should be, the problem is that the basic agreement does not get us very far.
Jennifer, I’ll reply later to your question.
Jennifer,
“Why do recommend the data be smoothed? Why is it appropriate here? And sometimes
to understand the potential contribution of a single component … it is necessary
to disregard the overall pattern.”
The reason lies in the difference between weather and climate. Climate *is* the pattern and that is what we are worried about so it can never make sense to “disregard the overall pattern”. Any single point in time is weather only. Smoothing removes the noise of weather and exposes the pattern of climate. That is precisely why one can not say that Katrina was caused by global warming, you can only say (maybe, this remains controversial) that Katrina type storms will become more common with global warming. 1998 is not significant to the overall trend, but it may be significant in determining a change in El Nino patterns.
Ian K,
Thanks for the “heart in the right place” comment 🙂 I sincerely want to keep my head in the right place too, and I really dislike the us vs them nature of climate science discussions so please if you see me “rush in” and overstate or misrepresent something, tell me and we will all learn more.
If I am too prolific here it is only because there seems to be alot of basic information missing in the climate science category and also because I appreciate that this blog has a better level of discourse than most (that’s a hat tip to you, Jennifer).
Ian Castles, I would be extremely surprised if the prediction of 1oC in 15 years you attribute to Hansen were correct, this is an order of magnitude faster than any other prediction I have ever seen attributed to him. It is also far higher than his extreme scenario prediction presented to the US Senate in 1988. If he had ever said such a thing it would be being put to use in the media attacks of recent months rather than recycling the Patrick Michaels 1998 lie to congress about aforementioned testimony.
http://illconsidered.blogspot.com/2006/04/hansen-has-been-wrong-before.html
I don’t think there is any useful information whatsoever for climate, let alone climate trends, in month to month comparisons. I would say this even if there were no seasonal cycle but there is and while I know it is summer in the south when it is winter in the north, there is still a global seasonal cycle dominated by the N Hemisphere. The very short term changes you are focussing on are weather, not climate.
Re B1, this entails emissions starting to decline by 2040. Isn’t China supposed to surpass the US by around 2030? How will world emissions stop growing by that time without dedicated effort? Anyway, with B1 I see close to 2oC more as the most likey rise with a high end range at 2.5oC not the 1.1 you quoted. It is not at all clear to me that this is not very problematic.
http://www.grida.no/climate/ipcc_tar/wg1/figspm-5.htm
It is a big mistake to mentally compare a 1, 2 or 3 degree rise in global average temperature to the day to day variation of sometime 10’s of degrees. When you put these numbers in historic context and examine the effects of similar changes in geological history you do not find that this is no big deal.
Wew! I am glad we all seem heading in the same direction and are just haggling over the price! Do we agree basically on IPCC sensitivities then?
I guess my take upon the graph is that, firstly, I am quite happy to take the advice of the experts and wait for the next report of the IPCC! I think there are so many uncertainties with its derivation and quality that I despair at forming an opinion.
However if I am to dare to place my own interpretation, I would first say that, being earthbound myself, I place much more faith in good old terrestrial thermometers. Second I would say that I agree with Ender on the significance of the heat sink effect and inertia of the oceans. The only extra point that I would add is that if Grey is to explain away the peak of 1998 as El Nino then that only goes to show how small changes in the warming of the oceans can mask a general warming trend in non El Nino years. Equally though less forcefully I would say that if particulates from two transitory volcanic events are having such an impact (as seems somewhat borne out) then perhaps anthropogenic aerosols are also a significant masking factor?
Ian Castles I appreciate your input. As you note, if Gavin thinks feedback factors are so easy why hasn’t it been done? If this is the case though it seems to cut both ways. Perhaps what Tom Fiddaman says at item 18 of that thread is the reason: “However, it’s ridiculous to suggest that a list of feedback factors combined with intuition would somehow be an improvement over the models themselves.”
Tom’s remarks and Mike Atkinson’s (at item 14) seemed useful to me in the context of the models. It is a pity that Gavin is so terse about it, but he usually seems to be.
Coby I didn’t wish to imply that you overstate or misrepresent anything. I appreciate your inputs.
Ian K, Thanks for your comments. In response to your question about whether we agree basically on IPCC sensitivities, let me haggle a little.
At the high-profile ‘Greenhouse 1988’ conference in Australia 18 years ago, Professor Ian Lowe, now President of the Australian Conservation Foundation, reviewed the various predictions of near-term climate change that had been presented and concluded:
‘My younger son is 35 years younger than I am; by the time he is my age, it is likely that the temperature will have increased by about three degrees’ (Living in the Greenhouse, p. 40).
We’re now at the half-way mark of Ian Lowe’s 35-year prediction. The ‘point-to-point’ increase in global temperatures between 1988 and 2005 is 0.36 deg C according to the GISS series and (I think) 0.19 deg C according to the MSU series. 1988 was, and I believe that 2005 will prove to be, above the 5-year moving average centred on the year concerned.
Adjustment for trend could not have more than a marginal effect on the prima facie conclusion that the observed warming has been proceeding at only a fraction of the rate that was widely expected in 1988. Why?
You suggest that anthropogenic aerosols may be a significant masking factor. They may well have masked some of the warming that might otherwise have occurred since the pre-industrial period, but this doesn’t seem to be true of the period since 1990. If anything, there’s apparently been some re-brightening of the earlier ‘dimming’ (though not everywhere) in this period.
This wasn’t anticipated so I suspect (I’m open to correction) that the gap between the model projections of the late 1980s and the trend in observations over the past decade-and-a-half would be even greater than is implied in the above figuring. Again, and given the fact that there’s be no significant change in the reported range of climate sensitivity, why?
Coby, It is trivially easy to produce seasonally adjusted and trend data corresponding to the crude monthly GISS and MSU temperature numbers. I’m surprised the producers don’t do this as a matter of course.
Compared with the problems of trading day, public holiday and Easter corrections which must be addressed in the reporting of economic data,
I don’t believe that these climate series are particularly difficult to interpret.
Day to day variations have nothing to do with it, and the prospective rises in global temperature of which you speak may or may not be realised.
The very short term changes that I focused on were a response to your claim that we won’t know the trend figure for 2005 for nearly two years.
We won’t know the PRECISE figure (assuming the observations are accurate) until then, but that doesn’t preclude earlier estimation – which shouldn’t require the sort of figuring into which I was forced by the lack of available data to assist interpretation.
I was surprised to see a recent posting to RC about the change in the Mauna Lao concentrations between March and April 2006, and how this compared with the corresponding movements between the same two months over the past ~50 years. This sort of speculation should be unnecessary.
Your comments about B1 effectively challenge the SRES projections. The team were explicitly required under their terms of reference to assume that no climate policies would be adopted, yet you are asking me how world emissions will ‘stop growing [by 2040] without dedicated effort.’
When Castles & Henderson offered a reasoned criticism of the SRES projections the IPCC accused us of spreading disinformation and of being ‘so-called’ independent commentators. Why should your unsupported doubts be taken more seriously?
The 1.1 deg C increase that I quoted for B1 came from Hansen et al (2005). The fact that you cite the IPCC as giving a 2 or 2.5 deg C increase for the same scenario is further evidence of the need for the kind of model comparisons I am suggesting.
My apologies Coby, my last comments addressed to you were cantankerous and go against the spirit of convergence (in views) which had been developing on this thread.
You are correct that achieving the B1 emissions profile requires ‘dedicated effort’, but by assumption that effort is directed to expanded R&D efforts to improve energy efficiency, agricultural productivity etc. in ways that will reduce emissions, NOT policies to reduce emissions that would have no justification other than climate policy.
On the issue of the response of temperatures to the B1 profile of emissions, Hansen et al (2005) come up with a much lower temperature increase this century than the IPCC TAR. Hansen et al are also much lower for A2 (increase of 2.7 deg. C in temperature). This is a puzzle and requires explanation.
Ian Castles, I heartily agree that Ian Lowe’s statement compressed the timetable of climate change alarmingly. I confess that I don’t yet know sufficient of the history of climate change science for that period to excuse or contextualize it.
If I can however put it in the context of his book (which I think I started reading at the time but never finished. Perhaps I was naïve but he didn’t manage to galvanise me!) Now, pages 40-41 also include tables giving changes in temperatures for Australia and the world on the assumption of doubling of CO2. It seems to me that these are pretty much in line with currently estimated sensitivities.
So his error, I can only assume, stem from the emissions scenarios of the time, not from climate science. Reviewing this, now historical document, only tends to make me trust the models more! This seems to me to undercut Garth Paltridge’s assumption that the modelers have unconsciously built a bias into their models over recent years. The models may well be converging but I don’t see a convergence to scarier predictions.
But I really think that we shouldn’t be too concerned about these atmospherics! I wish I had figures at hand for the respective heat capacities of the oceans, landmasses, cryosphere and atmosphere (though of course their lapse rates, mixing ratios, etc would need to be taken into account). I think such comparisons would be salutary. Perhaps if we changed “global warming” to “global heating” and said where the heat was going rather than what are the temperature changes we would have a better feel for the problem.
BTW you said on the thread concerned with AR4 that “in 1987, Richard Morgenstern alleged there was ‘an emerging concensus (sic) that the global warming could result in a rise in sea level on the order of two to seven feet (61-213 cm) by 2100’, and cited multi-authored books that had appeared in 1983, 1985 and 1987.
Ian Lowe, at page 44 of Living in the Greenhouse, states that : “The favoured scenario quotes the most common 1987 view, which was that the best estimate of the increase was 80 cm, but that the possible error was 60 cm in either direction.” My view, for what it is worth, is that an “emerging consensus” is only a TREND towards that happy state of affairs and that Morgenstern could have been referring only to an emerging consensus as to the range of MAXIMUM sea level rises, rather than minimum-maximum ranges. I really do not think such an interpretation is as bizarre as it may seem to you.
Ian C,
Re tone: Don’t worry about it! As for Hansen’s lower than IPCC projection with scenario B1 and A2, I will go out on a limb by not trying to find out and instead just suggest he may be including some of his other mitigation measures such as soot and methane reductions that he often talks about.
As for higher predictions before I think Ian K is probably right that this came from the extremity of the scenarios not high sensitivities. This highlights your issue with identifying realistic scenarios, and I would argue that as the models agree more and more on climate’s sensitivty to CO2, it becomes a higher priority to nail down the scenarios.
There is an update on Mauna Loa, March 2006 was anomalously low compared to 2004 and 2005. April is average.
http://home.casema.nl/errenwijlens/co2/co2_200420052006_compare_01.gif
full thread on:
http://www.ukweatherworld.co.uk/forum/forums/thread-view.asp?tid=899