The Copenhagen diagnosis

The big climate conference in Copenhagen last December has resulted in a disappointment. Although it can be argued that US president Obama is working very hard to address the climate issue and is making progress, Copenhagen came at a bad moment for the US administration.

Nevertheless, the stakes remain incredibly high. This becomes clear when one reads the Copenhagen Diagnosis, an update on the state of the science of global warming that has been issued by leading climate scientists, independently from the IPCC assessments that are issued every four years. Although the report has been made available already last December (obviously to coincide with the Copenhagen conference), I think it is important enough to call attention to even if I am a bit late to the party. It is freely available from For the impatient, I have copied the Executive Summary below.

The most significant recent climate change findings are:

Surging greenhouse gas emissions: Global carbon dioxide emissions from fossil fuels in 2008 were 40% higher than those in 1990. Even if global emission rates are stabilized at present-day levels, just 20 more years of emissions would give a 25% probability that warming exceeds 2°C, even with zero emissions after 2030. Every year of delayed action increases the chances of exceeding 2°C warming.

Recent global temperatures demonstrate human-induced warming: Over the past 25 years temperatures have  increased at a rate of 0.19°C per decade, in very good agreement with predictions based on greenhouse gas increases. Even over the past ten years, despite a decrease in solar forcing, the trend continues to be one of warming. Natural, short-term fluctuations are occurring as usual, but there have been no significant changes in the underlying warming trend.

Acceleration of melting of ice-sheets, glaciers and ice-caps: A wide array of satellite and ice measurements now demonstrate beyond doubt that both the Greenland and Antarctic ice-sheets are losing mass at an increasing rate. Melting of glaciers and ice-caps in other parts of the world has also accelerated since 1990.

Rapid Arctic sea-ice decline: Summer-time melting of Arctic sea-ice has accelerated far beyond the expectations of climate models. The area of summertime sea-ice melt during 2007-2009 was about 40% less than the average prediction from IPCC AR4 climate models.

Current sea-level rise underestimated: Satellites show recent global average sea-level rise (3.4 mm/yr over the past 15 years) to be ~80% above past IPCC predictions. This acceleration in sea-level rise is consistent with a doubling in contribution from melting of glaciers, ice caps, and the Greenland and West-Antarctic ice-sheets.

Sea-level predictions revised: By 2100, global sea-level is likely to rise at least twice as much as projected by Working Group 1 of the IPCC AR4; for unmitigated emissions it may well exceed 1 meter. The upper limit has been estimated as ~ 2 meters sea level rise by 2100. Sea level will continue to rise for centuries after global temperatures have been stabilized, and several meters of sea level rise must be expected over the next few centuries.

Delay in action risks irreversible damage: Several vulnerable elements in the climate system (e.g. continental ice-sheets, Amazon rainforest, West African monsoon and others) could be pushed towards abrupt or irreversible change if warming continues in a business-as-usual way throughout this century. The risk of transgressing critical thresholds (“tipping points”) increases strongly with ongoing climate change. Thus waiting for higher levels of scientific certainty could mean that some tipping points will be crossed before they are recognized.

The turning point must come soon: If global warming is to be limited to a maximum of 2 °C above pre-industrial values, global emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilize climate, a decarbonized global society –with near-zero emissions of CO2 and other long-lived greenhouse gases – needs to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050. This is 80-95% below the per-capita emissions in developed nations in 2000.

I highly recommend reading the report itself. It is only 64 pages, including clear graphs and a number of gorgeous pictures (and lots of citations of scientific papers for further reading, for those who share my luck of having internet access to peer-reviewed journals). It also very specifically addresses and debunks a number of layman arguments that have often been put forth against climate change (“CO2 increase historically trails temperature increase and therefore it still does now”, etc).

In my opinion the report is an example of scientific outreach at its best. The climate debate has become heavily politicized (the public debate, that is. Although there exists a fierce and lively scientific debate about the details, the genuinely scientific debate on the reality of man-made global warming is long over. The basics of man-made global warming have been firmly established using the same scientific principles that are found in other natural sciences, like my own field of astrophysics). Whatever climate scientists do, it will be held against them: if they don’t invest time and energy in outreach they will be painted as stuck in their ivory towers and out of touch, and if they do, they will be labelled activists. The Copenhagen diagnosis presents a very strong case that outreach from active climate scientists is crucial to the public conversation. And someone who tells a disturbing truth is not by definition an activist.

3 Responses to The Copenhagen diagnosis

  1. rogerthesurf says:

    There might be global warming or cooling but the important issue is whether we, as a human race, can do anything about it.

    There are a host of porkies and not very much truth barraging us everyday so its difficult to know what to believe.

    I think I have simplified the issue in an entertaining way on my blog which includes some issues connected with climategate and “embarrassing” evidence.

    In the pipeline is an analysis of the economic effects of the proposed emission reductions. Watch this space or should I say Blog

    Please feel welcome to visit and leave a comment.



    PS The term “porky” is listed in the Australian Dictionary of Slang.( So I’m told.)

    Dear Roger,

    thank you for being the first to comment on this newly started weblog. However, although I have a clear sense of wonder, I lack a clear sense of humour, for I did not find your website very `entertaining’. Most of it is devoted to insulting people. I don’t want my blog to become that vicious and will mark similar posts as spam from now on.

    For other readers: he starts off with a frontal assault insinuating conspiracies, corruption and incompetence of the usual suspects, including Rajendra Kumar Pachauri, the chair of the Intergovernmental Panel on Climate Changes (IPCC) who is blamed for not being a climate scientist but having a joint Ph.D. in Industrial Engineering and Economics instead.

    I’ve read this criticism before and it makes no sense to me. There are three working groups in the IPCC:
    – Working Group I: The Science of Climate Change (which is where the climate science stuff is assessed)
    – Working Group II: Impacts, adaptation and vulnerability (which covers a lot of economical issues as well)
    – Working Group III: Mitigation of climate change (a lot of economics and engineering, obviously)
    Two out of three isn’t that bad, is it? And as far as the working group on the science is concerned, like every group it has its own chairs as well and in this case they are prof. Thomas Stocker and dr. Qin Dahe. Naturally, both Stocker and Dahe have impressive resumes in climate science (Stocker’s here and Dahe’s here).

    Then we get a lot of noise about the medieval warm period (MWP), which was a local phenomena and not a global one as is asserted on the site. Globally, the planet was actually cooler than under current conditions. For a discussion of this see here, where you’ll also find a further link to a proper scientific paper on the subject.

    Then we get shown a plot by a biologist called Nasif Nahle (a biologist? so now climate science credentials all of a sudden no longer matter?), showing temperature variability in the holocene epoch. Note that nowhere in the plot we see the unprecedented large change in global temperature over a timespan of a mere century. Other than that, yes circumstances were different a gazillion years ago. I have it on good authority from my fellow astronomers that at a point in time before that, the earth actually consisted of a cloud of dust grains floating around a young sun. So? I hope it is not seriously suggested by Roger that the physical processes shaping the holocene are ignored by climate scientists, because understanding and including solar variability, changes in earth orbit etc. etc. is what climate science is all about. The newly arisen anthropogenic component is merely the tip of the iceberg, or in other words, the straw that will break the camel’s back. Of course, if Nasif Nahle has a serious point to make, I suggest he writes it up and gets it published in a scientific journal. Whatever his work is may be shocking enough for Nature or Science if it can withstand scrutiny, but he can also try other journals like EOS.

    Anyway, this is turning out to become a long and tedious response. The link to Roger’s site is in his comment above, so be my guest. You’ll know what to expect.

  2. rogerthesurf says:

    Sorry you didnt enjoy the satire of my site. Not sure why it was offensive though, presidents and royalty get worse than that:)

    Well one thing you may have noticed about my blog is that every fact had a source quoted which seems to be missing from your comments and tragically the IPCC sources are not standing up too well lately.

    I was under the impression that I actually DID provide sources, given the fact that I explicitly link to information about the chairs of the IPCC Working Group I (the one about the science) and to a discussion plus scientific paper on the Medieval Warming Period. The summary of the paper (Mann et al. Science (2009) vol 326, page 1256), is the following:

    Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally. This period is marked by a tendency for La Nina-like conditions in the tropical Pacific. The coldest temperatures of the Little Ice Age are observed over the interval 1400 to 1700 C.E., with greatest cooling over the extratropical Northern Hemisphere continents. The patterns of temperature change imply dynamical responses of climate to natural radiative forcing changes involving El Nino and the North Atlantic Oscillation-Arctic Oscillation.

    No matter what ones view on Global Warming may be, one fact remains and that is that the Anthropogenic CO2 – Global Warming hypothesis, is simply that – a hypothesis. There is no way of proving it without killing civilisation and there are a good number of facts that disprove it. Some you may have noted in my blog.

    A scientific hypothesis is more than just an idea, and should be taken more seriously the more it is confirmed. Besides, there is no single global warming hypothesis. If you would want to define a single statement, or most essential hypothesis, it would probably be along the lines of the current anthropogenic radiative forcings (i.e. CO2 levels etc. caused by man) have a net impact on global surface temperature, ocean heat content, total glacier mass, winter sea ice thickness etc. that currently exceeds (or is at least comparable and adds up noticeably to) that of any natural radiative forcing. But there are many other hypotheses that are connected to this one. Global warming will spell the end of civilisation is an extreme example, and not a hypothesis actually considered by climate scientists. Global warming spells disaster for agriculture and may therefore be indirectly responsible for people dying is yet another one, one to take a lot more serious if you’re a policy maker. Another hypothesis, which would probably disprove or at least seriously impact the main AGW theory if falsified, would be the average global surface temperatures over the next decade will be significantly higher than that of, say, the 1930’s. Let’s keep an eye on that one, shall we?.

    I hope you read where the IPCC 1990 report Fig 7.1 c1990 report Fig 7.1 c is shown, then how it was later replaced by the “Hockey Stick” graph and then you see the “scientists” in the climategate emails discussing how to explain this away.

    Most people would smell a rat at this stage.

    Oh by the way the Medieval Warm period coolings show up in historical records from Greenland to China and many warmings including the Medieval and Holocene are even apparent in Antarctic Ice Core analysis.

    See above. Note that the paper about the MWP that I quoted above is from 2009. The discussion on pages 468-470 of the IPCC 4th assessment report, working group I also links to many papers from after 1990. Published in 2007 (i.e. before the 2009 paper) it concludes

    The evidence currently [emphasis mine, hveerten] available indicates that NH [northern hemisphere, hveerten] mean temperatures during medieval times (950-1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn and Briffa, 2006). However, the evidence is not sufficient to support a conclusion that hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval tines (Jones et al., 2001; Bradley et al., 2003a,b; Osborn and Briffa, 2006).

    I see no inconsistencies here, and in the plots you present. The hacked e-mail shows scientists concerned that an illustrative (note the absence of error bars) plot, drawn at a time when less was known about the MWP, is being misused by people who wilfully ignore that it shows only trends and has been superseded by more accurate plots, like the ‘hockeystick curve’, which actually is a presentation of data and not just an illustrative plot (note now the grey error bar zone). Anyway, the precise temperature during the MWP is a single (but interesting) detail in the whole of AGW science, and even back in 1990, when it was less well understood, it did not undermine the sad conclusion that anthropogenic global warming was and is occurring.

    I find your assertions about scientists trying to change history (“scary stuff!”) a bit silly. The old IPCC reports can still be found in the libraries, it’s not as if George Soros is buying all copies and burning them… wait, did I just hear a black helicopter circling above my house?

    Here is a link to the most recent report in Antarctica. They sound disappointed its true and I wonder that they stick to their predictions.


    You are always welcome to leave a message on my site because 1. I welcome all reasonable and supported points of view 2. I am not afraid of dissenting opinions because my mind is always open.



    Oh and please watch for my economic analysis of the effects of the emission reductions that are on the IPCC agenda. I think thats the most frightening thing.

  3. rogerthesurf says:

    I prefer you answer nay comments instead of editing answers.

    Then this must be very irritating to you… let me ponder this. Am I trying to keep the conversation focussed or am I interrupting? I may decide to change how I do this in the future.

    First of all, the IPCC is increasingly showing to be unreliable in its reporting and misinformation. If one wants to refer to anything, its no use refering to their literature for the truth. There is however plenty of unbiased literature around, especially historic records and archaelogical findings which are difficult to twist out of shape. Which is why I concentrate on such in my blog.

    The IPCC working group I report (the scientific basis) holds up just fine under scrutiny. You may be referring to something like the glacier error in working group II report (impacts, adaptation & vulnerability), where they repeated a typo from some ‘grey’ literature that they cite (‘grey’ being non peer-reviewed, they occasionally cite such sources along with peer-reviewed papers, which is completely conform their stated conventions). However, we’re not talking about the scientific basis report but about one of the others written by non-climate scientists, people who indeed really should have consulted the actual scientists even if they were in a hurry because of deadlines. Still, the extremely low number of actual errors of this type in a series of reports that are thousands of pages long is to me more impressive than embarrassing. Leaving aside the error with the reference to the grey literature, my little quote alone from the IPCC report contained a lot (five) of cites of peer-reviewed papers, which should actually have made you very happy.

    You seem to have trouble understanding what a hypothesis is. [1] And it is an incontravertible fact the the hypothesis that “Human induced CO2 in the atmosphere causes climate change”, is a hypothesis that is unproven because it is impossible to prove. Its no use building weather models with the hypothesis as an assumption and saying this proves the hypothesis.
    However the fact that the earth commonly has warm periods and cool periods in the absence of any correlation with CO2 in the past, most certainly disproves the hypothesis.The medieval warm period was of course simply the most recent. The holocene maximum for instance was even warmer and at that time the Sahara was lush and fertile.

    When the CO2 forcing is not completely dominant, no clear cut correlation appears. The fact that there is one now is extremely troubling. The effect of the CO2 forcing at historical times is not absent however, and is actually used as ingredient in climate modelling. We’ve been over what a hypothesis means in my previous response and I stand by that.

    If you cant read in the climate gate emails how the “scientists” are discussing ways to explain away their publishing of the graph showing the medieval warm period in their 1990 report Fig 7.1 c then you are selectively blind. [2]

    Here is the link about the lack of antarctic warming. I know they make some predictions that it will start warming there soon, but I prefer to stick with the facts, not speculation.

    I recommend everyone to check out this link and see what it actually says. Roger appears to have an optimistic intepretation of key point 1 of the summary:

    1. Hole in ozone layer has shielded most of Antarctica from global warming
    The ozone hole has delayed the impact of greenhouse gas increases on the climate of the continent. Consequently south polar winds (the polar vortex), have intensified and affected Antarctic weather patterns. Westerly winds over the Southern Ocean that surrounds Antarctica have increased by around 15%. The stronger winds have effectively isolated Antarctica from the warming elsewhere on the planet. As a result during the past 30 years there has been little change in surface temperature over much of the vast Antarctic continent, although West Antarctica has warmed slightly. An important exception is the eastern coast of the Antarctic Peninsula, which has seen rapid summer warming. This warming is caused by stronger westerly winds bringing warm, wet air into the region from the ocean.

    Even this point alone doesn’t seem all that reassuring to me, and that’s even before reading other key findings like point 2, 3, 4:

    2. Warming of the Southern Ocean will cause changes in Antarctic ecosystem
    The largest ocean current on Earth (the Antarctic Circumpolar Current) has warmed faster than the global ocean as a whole. The Southern Ocean is one of the major sinks of atmospheric CO2, but increasing westerly winds have affected the ocean’s ability to absorb CO2 by causing the upwelling of CO2 rich water. If temperatures continue to rise ‘alien’ species may migrate into the region, competing with and replacing original Antarctic inhabitants. Key species in the food chain like planktonic snails could suffer from ocean acidification. Changes in the food regime are likely to decrease the rich Antarctic seabed biodiversity.

    3. Rapid increase in plant communities across Antarctic Peninsula
    Rapid warming has been seen along the western Antarctic Peninsula, along with a switch from snowfall to rain during summer, resulting in expansion of plant, animal and microbial communities in newly available land. Humans have also inadvertently introduced ‘alien’ organisms such as grasses, flies and bacteria.

    4. Rapid ice loss in parts of the Antarctic
    The West Antarctic Ice Sheet has significantly thinned particularly around the Amundsen Sea Embayment as a result of warmer ocean temperatures. Regional warming caused by intensification of the westerly winds (due to the ozone hole) is melting ice shelves along the eastern Antarctic Peninsula (e.g. Larsen B Ice Shelf). Overall, 90% of the Peninsula’s glaciers have retreated in recent decades. However, the bulk of the Antarctic ice sheet has shown little change.

    Anyway, go read it everyone.

    Here is another link if you have enough guts to have your faith threatened.[3] Allow over an hour though because it is a good exhaustive doco.

    After you have honestly [4] watched it I will be interested to hear your critique.

    That’s a coincidence, watching that joke of a documentary when it appeared on Dutch television a few years ago was actually one of the things that got me worked up about climate in the first place. I was triggered by the unfounded accusation that climate scientists were ignoring the sun’s role, but after watching the documentary I had a feeling there were more things amiss than I spotted directly, so I did some googling. If even the scientists who appear in the documentary are pissed of by how their words are twisted, you should, in your words, ‘smell a rat’:

    By its placement in the film, it appears that I am saying that since carbon dioxide exists in the ocean in such large quantities, human influence must not be very important—diametrically opposite to the point I was making—which is that global warming is both real and threatening.”
    “Durkin [the producer, hveerten] “clearly quite deliberately understood my point of view but set out to imply, through the way he uses me in the film, the reverse of what I was trying to say”

    That was Carl Wunsch the oceanographer, and he himself elaborates further here. Even Eigil Friis-Christensen was not amused (quote from here):

    We have concerns regarding the use of a graph featured in the documentary titled ‘Temp & Solar Activity 400 Years’. Firstly, we have reason to believe that parts of the graph were made up of fabricated data that were presented as genuine. The inclusion of the artificial data is both misleading and pointless. Secondly, although the narrator commentary during the presentation of the graph is consistent with the conclusions of the paper from which the figure originates, it incorrectly rules out a contribution by anthropogenic greenhouse gases

    Producer Durkin’s response to criticism (from someone else than EF-C) about the plot leave little to the imagination: You’re a big daft cock and Never mind a bit of irresponsible film-making. Go and fuck yourself. Now THAT’s who you should be calling a porky, Roger!



    Note the little black numbers, Roger? You’re one strike over the limit and you’re out. Anyone incapable of a civil conversation will be banned.

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