RealClimate logo

Technical Note: Sorry for the recent unanticipated down-time, we had to perform some necessary updates. Please let us know if you have any problems.

Cold Case vs. CSI

Filed under: — gavin @ 14 February 2007 - (Slovenčina)

If you are a follower of TV crime shows, it is likely that you’ve come across one of the CSI offshoots (CSI stands for Crime Scene Investigation) and a slightly less well known show called ‘Cold Case‘. In both these shows, difficult crimes (usually murders) are solved using the most up-to-date forensic methods and incredible detective work. However, it will be obvious to even the most jaded TV watcher that the CSI crew get to have a lot more fun with the latest gadgets and methodologies. The reason for that is clear: with a fresh crime scene there is a lot more evidence around and a lot more techniques that can be brought to bear on the problem. In a ‘Cold Case’ (where the incident happened years before), options are much more limited.

Why bring this up here? Well it illustrates nicely how paleo-climate research fits in to our understanding of current changes. Let me explain….

For the last 30 years or so, the amount of information we have about the planet has gone up by a couple of orders of magnitude – mainly due to satellite information on atmospheric (radiation, temperature, humidty, rainfall, cloudiness, composition etc.), ocean surface (temperature, ice cover, windiness) and land properties (land cover, albedo) etc. Below the surface, we are now measuring much more of the ocean changes in heat content and carbon. This data, while still imperfect, has transformed our view of the climate such that the scientists studying it can seriously discuss details of problems that twenty years ago were not even thought of as issues. “CSI – Planet Earth” if you like.

Comparatively, the amount of information we have for any period in the past is less – hundreds (in some cases a few thousand) of records of climate ‘proxy’ data (i.e. records that are related to climate, such as tree rings ot isotope ratios, but that aren’t direct thermometers or rain gauges) that are not necessarily optimally spaced, nor necessarily well-dated, nor uncontaminated by non-climate influences. However, there is the great advantage of a much longer time period to work with, as well as a greater variety of changes to investigate. Think of the people that work on that as the ‘Cold Case’ crew.

The most prevalent reasonably scientific question about current climate changes is ‘how do we know that this isn’t natural variability?’. A number of versions of that question came up in the House hearing last week (a nice report from the proceedings can be found here). Some of those comments were serious, some were ridiculous, but all essentially pointed to the same issue. Kevin Trenberth and Richard Alley answered it best when they pointed out that the causes of ‘natural variability’ – whether the sun, volcanoes or ocean changes – should be detectable (but haven’t been), and that the anthropogenic ‘hypothesis’ should have consequences that are also detectable (which have). Add in the modelling studies which indicate that current conditions can’t be explained without including greenhouse gases and you have a pretty solid case that what is happening is in large part anthropogenic.

A rather more specious comment heard often (including at this hearing) is that ‘if it was warmer before, then the current warming must be natural’ or alternatively ‘if you can’t explain all of the past changes, how can you explain anything now?’. First of all, there are many periods in Earth history that are unequivocally accepted to be warmer than the present – the Pliocene (3 million years ago), the Eocene (50 million years ago) and the mid-Cretaceous (100 million years ago) for instance. Less clearly, the Eemian interglacial period or the Early Holocene may have been slightly warmer than today. Thus, if that logic were appropriate, no-one should bother worrying about climate change until sea levels start to approach mid-Cretaceous levels (about 100m above today’s level!).

However, the logic is fatally flawed. It is akin to a defense lawyer arguing that their client can’t possibly have committed a particular murder because other murders have happened in the past that were nothing to do with them. That would get short shrift in a courtroom, and the analgous point gets short shrift in the scientific community too. Of course, it is possible that our suspect was involved in previous murders too – but obviously the further back you go, the harder it is to pin it on them. And clearly, there will be past murders where they have a clear alibi.

A better tactic for the defense is obviously to try and pin it on someone else – and if that someone else has a record – then all the better. Therefore, ‘the sun did it’ is a frequent accusation, but as we have discussed here quite often, this time around the sun has an alibi and there are reliable witnesses to back him up.

Given the better information and resources available for the CSI crew, it is natural that their assessment of the current case will generally hold sway. Cold Cases (or paleo-climate) are of course of paramount interest: they provide a much wider set of conditions that set the stage for the modern analyses and provide plenty of test cases for us to hone our techniques (such as climate modelling). However arguments from paleo are extremely unlikely to trump the modern analyses – whether they refer to the medieval warm period or the Phanerozoic.

So to summarise, CSI-Planet Earth have a good case for pinning the latest warming on greenhouse gases. Cold Case has evidence that they were involved in some previous cases (the last glacial period for instance), though they’ve definitely ruled our suspect out for a few others (e.g. the 8.2kyr event). It would be hard to argue that our suspect should be acquitted because there have been some crimes they didn’t commit!

Update: I should have linked to this Newsday piece: Hot on their global trail by Bryn Nelson where I first tried out this analogy.

168 Responses to “Cold Case vs. CSI”

  1. 151

    False analogy. If either show used computer models to predict murder patterns 100 years in the future they would be broadcast on the Sci Fi channel.

  2. 152
    Hank Roberts says:

    Marco, 650,000 years is the record for ice core data. You write “It did not mention whether it caused mass extinction or other visible results at that time. I can only assume that they don’t know or the evidence doesn’t show this.”

    Well, okay.

  3. 153
    Steve Bloom says:

    Re #125: Dave D, you may already know about this, but go here and look at the several papers relating to ice bubbles. Who knows, it might even have what Sashka wants.

    Re #150: “The site seemed to be sponsored by environmental groups.” PMEL? Marco, that’s a NOAA lab. And you say a report issued by NSF, NOAA and USGS is “quite heavy on the environmental propaganda.” Do you have any idea what those organizations are? Maybe you should look then up. And if I were you I’d consider cutting back on those “X Files” reruns.

  4. 154
    Hank Roberts says:

    Geology; March 2003; v. 31; no. 3; p. 211-214

    Missing molluscs: Field testing taphonomic loss in the Mesozoic through early large-scale aragonite dissolution
    Paul Wright*,1, Lesley Cherns*,1 and Peter Hodges*,2

    1 Department of Earth Sciences, Cardiff University, Cardiff CF10 3YE, UK
    2 Department of Geology, National Museum of Wales, Cardiff CF10 3NP, UK

    It appears that major aragonite dissolution normally distorted both apparent diversity (65% decrease in bivalve diversity) and the trophic structure of the offshore facies, providing aragonite that probably sourced the diagenetic carbonates. We suggest that aragonitic shells were selectively dissolved in the upper sediment column in lower-energy settings, where high organic contents favored microbial decay and acidity; such early dissolution was absent from the higher-energy facies that originally had low organic contents. Taphonomic loss through early skeletal aragonite dissolution was an equally important process in Mesozoic offshore shelf environments, and although still leaving depleted molluscan-dominated faunas, resulted in a massive distortion of diversity.

  5. 155
    Lynn Vincentnathan says:

    RE #151, well, actually the analogy breaks into reality at that point, because that’s what we’re doing through anthropogenic global warming & its harms, killing future people. That’s the whole point.

    And I don’t base my predictions using computer models, but from looking at past GW events, such as those 55 & 215 mya. Only this time, we’re the ones triggering this major extinction level event, with nature due to take over in emitting GHGs (& failing to absorb) in response to the warming we are now causing, on top of the reducing albedo effect. It’s a tough pill to swallow. Makes one want to believe the denialists, rather than own up to it and take responsibility.

    I also don’t need the denialists’ 99% certainty or the scientists’ 95% certainty to reduce my GHGs (which I started doing in 1990). The paradigm for thinking about this, 1st proposed by the father of statistics, Pascal, is: If GW is happening and we do nothing to mitigate it, we may be headed for a hellish world. If GW is not happening, and we reduce our GHGs thinking it is happening, we are headed for a much more efficient and productive economy.

    So what do you say? Come help us mitigate AGW. Reduce, reuse, recycle, use alternative energy when feasible. Every little bit helps. The future peoples will greatly thank you.

  6. 156
    Joseph O'Sullivan says:

    #16 Raypierre, your analogy is very interesting. It reminds me of how evidence is admitted into court.

    Normally past crimes can not be mentioned to a jury. Once the jury hears that the accused is a convicted criminal they tend to jump to the conclusion that he must also be guilty of the crime he is charged with now. To properly decide the jury must look at the evidence of the crime in question and not be misled or prejudiced.

    There is an exception to this rule. If there is a pattern that fits the current crime, a jury can hear about a prior conviction, but there has to be consistent pattern. Someone might have multiple convictions for drunk driving, but this is not a pattern that would show this same person is likely to be a bank robber. If the accused has multiple convictions for robbing banks it is telling if he is being charged with another bank robbery. There is a shown past pattern that can help answer the question at hand.

    For the comments discussing ocean acidification, there was a symposium on the effects of ocean acidification this past summer. The take-home message seemed to be that there is not enough known to draw firm conclusions, but the early evidence does not look good for the oceans.

    In the recently passed bill reauthorizing the Magnuson act, there is a directive for the National Research Council to examine the effects of ocean acidification. From the bill: NOAA will “request the National Research Council to conduct a study of the acidification of the oceans and how this process affects the United States”.

  7. 157
    Dave D says:

    Re #153 Thanks Steve. This is a great source. I’ll read more, but it does seem that the trap time can be long in low accumulation rate sites.

    In fact, I think the lag of CO2 concentration behind the temperature record is due to this integration time.
    Temperature is determined by hydrogen/deuterium ratio of the ice itself. This is instantaneous (delta function impulse response), as opposed to the air which is a running average (integrator). Think about how a running average responds to a small step function, then consider the real input CO2 signal as made of a bunch of small steps. You get a lag of the integration time.

    Someone has probably already thought of all this, but I have seen some discussions going back and forth on what the lag means for climate dynamics (CO2 vs. Temp … chicken or the egg). Maybe its a perfectly reasonable artifact of the system functions of the two processes.

  8. 158
    Hank Roberts says:

    > The take-home message seemed to be that there is not enough known to
    > draw firm conclusions, but the early evidence does not look good for the oceans.

    No, no, no. Great paper, but I disagree with the summary. Quoting a bit:

    “While much work remains toward answering the fundamental question: ‘How will marine calcification rates respond to increasing atmospheric CO2 concentrations,’ we need to begin investigations that look forward to answering the question: ‘What are the consequences of reduced calcification in both planktonic and benthic calcifying communities and ecosystems?’ We should not wait until we answer the former question before tackling the latter.

    “This report is intended as a guide to program managers and researchers toward designing research projects that address these important questions.”

    This is the _research_ proposal guide. It focuses on where research is needed. They know the situation overall:

    “There is clear evidence that the carbonate equilibrium of the oceans is shifting in response to increasing
    atmospheric CO2 concentrations….. dissolution rates of carbonates will increase in response to CO2 forcing. Even small changes in CO2 concentrations in surface waters may have large negative impacts on marine calcifiers and natural biogeochemical cycles of the ocean …

    “… example, a rapid volcanogenic increase in pCO2 at the Triassic-Jurassic boundary (Palfy, 2003)
    coincides with a major extinction event, a worldwide interruption of carbonate sedimentation, and an evolutionary replacement of aragonite with calcite (Palfy, 2003; Hautmann, 2004). Furthermore, there is evidence that groups of calcifying organisms have become more or less dominant over geologic time, depending on CO2 levels, and is likely linked to their utilization of dominant carbonate species in the ocean. For example, comparison of atmospheric CO2 fluctuation from the Cambrian through the Cenozoic, to dominance trends for cyanobacterial and algal calcifiers, demonstrate that cyanobacteria dominate during periods of high CO2 …”

    This is the issue: the species we rely on for cycling ocean CO2 can’t form their shells at ocean pH levels sure to occur in large parts of the oceans by 2100 — within this century the pteropods and other calcite- and aragonite-shell-forming species that currently dominate the oceans will be replaced. Question is, how?

    They go methodically through the denials:

    Misconception 1. Increasing atmospheric CO2 will increase rather than decrease pH of marine waters. This argument is based on an incorrect assumption …..
    “Misconception 2. CO2 fertilization of zooxanthellae will lead to an increase in coral calcification ….

    “Misconception 4. The effect of global warming on calcification will outweigh the effects of decreased saturation state…..”

    It’s a very good paper, I’m glad you point to it. I just don’t agree with your simple one line summary.

    The take-home message is — lacking research as proposed — we can only hope evolution may operate fast enough in selecting among marine plankton species that something will replace the pteropods.

    My one sentence summary:
    Right now we have only faith-based planning — a faith that some plankton species will promptly take over removing CO2 from the ocean this century — a faith that evolution is our friend, and will protect us.
    Seriously, read this paper. Don’t rely on any one line summary, look at their sources (cited in earlier posts here too).

  9. 159
    Chuck Booth says:

    Re #150 “The site seemed to be sponsored by environmental groups. It seemed to be light on the facts and figures, but quite heavy on the environmental propaganda.”

    Umm…Marco, which site are you talking about? Look at the URL ( better yet, visit the site and actually read the text: The site is maintained by the NOAA Pacific Marine Environmental Laboratory (pmel) in Seattle and highlights its Carbon Dioxide Program, which “conducts ocean carbon cycle research from ships and moorings in all of the major ocean basins in collaboration with AOML’s CO2 Program” (AOML = NOAA’s Atlantic Oceanographic and Meteorological Laboratory). The report was sponsored jointly by the U.S. National Science Foundation, the National Oceanic and Atmospheric Administration, and the U.S. Geological Survey. The scientists who authored the report are listed in the document. If you want to discredit the science, or the scientists, you are free to do so, but how about doing it based on scientific grounds – your comments quoted above make you look foolish.

    Moreover, you initial question misses the important point – there well may be no documented extinctions yet – that is beside the point: There is strong evidence that several taxa of marine calcifiers are at risk of extinction due to changes in carbonate solubilities with acidification- this is clearly explained in several of the reports I cited in my initial post (#142), and in those cited by Hank Roberts.

  10. 160
    Joseph O'Sullivan says:

    #158 Hank Roberts

    My understanding of the ocean acidification issue is that its harder to figure out what the effects will be than climate change. Short term changes like el nino are temperature changes that give clues to what a warmer ocean will do to ecology, but we have no recent change in ocean chemistry to compare the recent ocean acidification to.

    Yes, no one should accept my one sentence summary without doing more reading.

  11. 161
    Vincent says:

    So what does that mean, murders and global warming are both good for science & technology? This is a kind of James Glick ignorance of fundamental physics and thermodynamics. So institutional scientists use ever diminishing and accelerating methodological & technical means to try and understand ever increasing disorders and instability.

  12. 162
    Roger William Chamberlin says:

    I think that concentrating on whether global warming is man-made or natural is to miss the point completely… the facts appear to show that BOTH effects are combining and it matters not which is greater [although perhaps it is becoming clear that men are the major cause] …

    What matters to life on earth is how rapidly it changes and what is the peak … there is now substantial evidence that the RATE of change is too high for species to move North to be able to live at their optimal conditions , as much a four times too fast a change … we simply cannot afford to allow nature to die off in this fashion in the name of making our lives more ‘convenient’ for a while [because they will become very seriously inconvenient rather quickly as our food supply fails]

    There is equally rather obvious danger in letting the temperature go too high, people are already dying worldwide and having their way of life destroyed by climate change and teh CO” in teh atmosphere continues its work for centuries … there is a delay between taking action and the temperature stopping rising and we have not even begun to act to stop our insane adding to the problem for people and life in general in the future… the peak temperature is critical to the extent to which life survives on this earth, billions of human lives are at stake besides much of the ecosystem itself… and evry day we delay pushes the final peak critically higher besides increasing the rate… and the rate of rise is still increasing!

    It is time mankind came to its senses if it can express them at all, we need to stop the way we are living in teh West and sttop exporting it to the East too… that is a massive task that needs to start now if we are to have any hope of saving at lest some of life on this planet … we ahve walked blindly into a TRAP because of the insidiousness of the onset of the problem and the fact that even when te problem becomes obvious it takes many decades to even start addressing it and centuries for te world to recover…

  13. 163
    Marco Parigi says:

    re #158If you want to discredit the science, or the scientists, you are free to do so, but how about doing it based on scientific grounds – your comments quoted above make you look foolish.

    Well, I don’t really have a defence, but I was very frustrated by only being able to get the abstracts, and requiring subscription to get anymore. The homepage I was looking at appeared to my eyes as very propaganda-ish and biased. I have no qualms at pushing buttons. Thanks for the good links, and especially for the overviews and your own unbiased views.

  14. 164
    Hank Roberts says:

    > we have no recent change in ocean chemistry to compare

    Um, except what’s described in the literature. Some experiments you do not want to do outside a lab, because you can see in the geological strata what happens to your nice planet when you do them.

  15. 165
    Joseph O'Sulivan says:

    Me #156 The take-home message seemed to be that there is not enough known to draw firm conclusions, but the early evidence does not look good for the oceans
    Hank Roberts #158 No, no, no

    I will try to explain one more time, one more time, one more time ;) Hopefully the third time will be the charm.

    I have surveyed the literature on ocean acidification. For the effects on ecosystems and individual organisms the literature is light on the effects, both in lab experiments and open ocean measurements. The summary of the symposium about the effects of acidification on organisms and ecology sections stated repeatedly that early results of the few studies done on this show that there could be serious negative effects, but there is little specific data to go on. The big picture is that ocean acidification is bad, even catastrophic, but there are details that need to be worked out.

    Climate-induced changes in carbonate chemistry could diminish the abundance of microscopic open-ocean plants and animals that build calcium
    carbonate structures. Some of these highly abundant organisms influence ocean-atmosphere interactions, but our knowledge of this influence and these interactions is rudimentary, making it difficult to predict the consequences of any chemical changes.
    -Coastal and Marine Ecosystems and Global Climate Change p.51 Pew Center for Climate Change Aug. 2002

    Potential biological impacts of both passive invasion of anthropogenic CO2 into the surface ocean and active sequestration of carbon in the ocean are only poorly known.
    -The Ocean in a High CO2 World; Oceanography Sept. 2004

    Weakness of Royal Society report The report was weak on biology because very few relevant experiments have been conducted.
    We do not know what changing ocean chemistry will do to marine biota (other than some calcifiers) and especially we do not know what the long-term chronic effects will be on ecosystems
    -Ken Caldeira Comment #41 The Acid Ocean RC post

    Resonse to my comment (#39) World Wide Glacier Retreat post
    Response: You may also be interested in the article by Richard Feely and colleagues, Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans arguing that quite apart from any climate impact from atmospheric CO2, there is a much more direct impact from the dissolution of CO2 in the world’s oceans. Richard has said that the scientific community has dropped the ball on this one, and we should have been warning the public about this particular catastrophe a long time ago, when it was first suspected. Unfortunately, and despite the name calling we get, we scientists tend not to raise alarms until we are very sure. I think Richard is now very sure

    I will add that not enough research has been done by the scientists to warn the pubic.

  16. 166
    Lynn Vincentnathan says:

    #162, “I think that concentrating on whether global warming is man-made or natural is to miss the point completely… the facts appear to show that BOTH effects are combining and it matters not which is greater…”

    The way I look at it is that we humans only have some control over our own GHG emissions, not directly over nature’s emissions, so I take an anthropocentric approach (though climate scientists may tend to take your more geocentric view).

    Nature’s GHG emissions that can be attributed to the warming which we humans have caused by our GHG emissions, should also be attributed to humans, even though we did not directly emit them. Or, the total warming that our emissions cause should also include this positive feedback of warming-nature’s emissions-extra warming, to get a more accurate assessment of the ultimate warming & ultimate harms (& some benefits) our emissions cause — their direct & indirect consequences.

    While this may be near impossible to quantify due to lots of uncertainties and unknowns, esp into the long-term future (some of our CO2 may be in the atmosphere up to 100,000 years), at least we should have the model in our minds….that there’s more bang per bucket of our daily emissions than we’ve been assuming.

    And conversely our reductions will have a much greater positive impact (or avoidance of negative impacts) than we currently realize under a more linear, time-constrainted, positive-feeback-lacking mental model.

  17. 167
    Lynn Vincentnathan says:

    Re #156 & 158, I guess the view we as nonscientists-concerned-about-the-world and proactive-policy makers should probably take is not whether the science on ocean acidification is in beyond a reasonable doubt, but the actions that produce our GHG emissions have many negative impacts, which is all the more reason to reduce: GW, ocean acidification, acid rain (from SO2 & NOx), local pollution, wars to secure oil (and perhaps some 50+ other negative impacts, and 1,000+ negative reverberations from those negative impact, including farmer suicides due to droughts).

    Perhaps the analogy should shift to responsible parents taking the chemistry set away from Jr, when they come to know he’s building bombs. We don’t know if he really has the capability to do that, but we need to stop his experiment, to be on the safe side. Likewise we need to halt this ocean acidification & global warming experiment on the oceans and earth BEFORE the dangerous results can be confirmed at 95% confidence (or even 50% confidence).

    Let’s just never find out!

  18. 168
    Joseph O'Sullivan says:

    There has been a recent development in the news regarding ocean acidification. An environmental group, the Center for Biological Diversity (CBD) has petitioned (sued) to have CO2 listed as a pollutant under the Clean Water Act.

    This is different than the recent Supreme Court case which was about listing CO2 as a regulated pollutant under the Clean Air Act. Getting CO2 emissions regulated and reduced under the Clean Water Act may be easier, but in some ways may be harder. If there were more studies specifically about acidification’s effect on ecosystems there would be a stronger case.

    The Center for Biological Diversity was a participant in the recent petition to get polar bears review for endangered status and the petition getting corals in the Caribbean listed as endangered. For both anthropogenic climate change is a major threat.

    Here’s a news story and a press release:

    Yes this is off topic, but my comments on RealClimate usually are off topic.

Switch to our mobile site