Overstretching Climate Change Attribution

Says Camille Parmesan and others, “The biological world is responding rapidly to a changing climate, but attempts to attribute individual impacts to rising greenhouse gases are ill-advised” (from the first issue of Nature: Climate Change).

With everything after the “but” I heartily agree. However, à la Bill Clinton, the truth of the entire sentence depends on what the meaning of “is” is. More of that in a moment. First, let us celebrate that a few members of the Consensus had the guts to say “Slow down!” in print.

Climate change is made of toads and snails and puppy-dogs’ tails. I mean, if there isn’t already, then there soon will be peer-reviewed papers that threaten plagues of toads, surfeits of poisonous snails, and unexpected shortenings of puppy-dog’s tails, all caused by that great maleficence of our time, climate change. “It is the organiser of half that is evil and nearly all that is undetected in this great [world].” It is the Moriarty of sciences.

All know this. Yet Parmesan was brave and said, “It is rarely possible to attribute specific responses of individual wild species to human-induced climate change.” And then came the Holmesian logic:

This is partly because human forcing of the climate is only detectable on large spatial scales, yet organisms experience local climate. Moreover, in any given region, species’ responses to climate change are idiosyncratic, owing to basic differences in their biology. A further complication is that responses to climate are inextricably intertwined with reactions to other human modifications of the environment. Even where climate is a clear driver of change, little insight is gained by asking what proportion of the overall trend is due to greenhouse gases versus solar activity.

The IPCC, however, cognizant of its role of spiritual leader and grants justifier, insists biologists begin “assessing the extent to which observed biological changes are being driven by greenhouse-gas-induced climate change versus natural climate variability.” The debate is over, warming is caused by humans, now show us how all biological changes are due to human activity! (Only bad changes, please; those changes that are good are in spite of climate change, not because of it.)

But Parmesan counters, “the probability of successfully attributing climatic trends to greenhouse gases declines sharply at spatial scales smaller than 106 km2 and at temporal scales shorter than 50 years”, so “it is inappropriate to attribute single events to anthropogenic climate change.”

In other words (my words), the risk of falsely asserting a biological change is due to human activity is large. Charge people to attribute untoward shifts in biological system to humans guarantees they will discover such attributions, whether they are true or not. Even the diciest “attribution” will find its way to print, because the subject will be deemed too important to ignore and because of the eternal reason, “Just in case.”

What makes it worse is that each time an attribution reaches the press, it will taken as more evidence that climate change is here and out to get us. An organism that changes its behavior (in a statistical sense) is only indirect evidence that climate changed. This is because biological changes, rapid or slow, can be caused by things other than climate.

For example, this statement from Parmesan is false, “As biological impacts provide evidence of climate change independently of temperature measurements, they have successfully bolstered ‘detection’, strengthening the scientific consensus that Earth is warming.”

To determine climate change, all we need is a thermometer and a rain gauge (or their equivalents, etc.). We do not need to examine the spoor of Moose or the chemical composition of prairie grass. The evidence of biological changes is not independent of the evidence we have from thermometers (and satellites, etc.). Further, it is silly to use Moose poop or tree rings when you could have used a thermometer.1

This is widely misunderstood. People hear that arctic thermometers register an increase and then hear that ice near that thermometer melted. There is only one piece of evidence here, not two. Ice melting is an effect of the temperature increase. It is not independent evidence of the increase. If we also measure an increase in abundance of some warmth-loving organism by the thermometer, we have not added independent evidence of temperature increase. Ice melting and organisms thriving are what happens when it gets hot out. We do not have three pieces of evidence, we still have just one.2

Thus, all the reports of fuzzy animals suffering, or of bad animals, bugs, and bacteria thriving, are not independent evidence of climate change. And the chance that changes in these beasties can be put down as caused by human activity is small. But there is little hope that Parmesan’s warning will be heeded. The temptations to “discover” attributions are too large and lucrative.

Update To clarify: if we can only say with low probability a given meteorological event is caused (indirectly) by man through climate change, the uncertainty in asserting that changes to an organism that is influenced by the meteorological event is vastly greater. This uncertainty is like multiplying probabilities: the result must be less than either probability.


1If no thermometer exists, then proxies can be used. However, click the “Stats/Climate” link at the top of the page for where this can and has gone wrong.

2It is an entirely different question what caused the temperature increase. An increase is evidence for man-made global warming; but it is also evidence for other theories of climate change (most of which you have not heard of, the press being as busy as it is). Which is the best theory remains unknown.


  1. Ken

    I bet that if some enterprising, and patient, person were to dredge up the old Nazi research papers on eugenics they merely substitute a few nouns here & there & have an instant climate change paper. Similar logic & all were at play…and people still use the same nonsensical tactics for whatever label is du jour.

  2. Ray

    I still remember that in the 1970s we were all going to die from global cooling. There were even computer programs that foretold our doom. There were going to be massive crop failures and millions would starve in the 1980s. That didn’t work out so then we were all going to die from global warming. That doesn’t seem to be happening, so now the disaster du jour is that we will all die from climate change.

  3. Speed

    Canaries are no longer used as proxies for gas in coal mines. Machines are more sensitive and reliable.

  4. DAV

    To determine climate change, all we need is a thermometer and a rain gauge ? I had heard that studying the entrails of the Green Treehugger also works but, while more satisfying perhaps, a thermometer and rain gauge are undoubtedly simpler to use and less messy to boot.

    OK. Melting ice is more corroborative than independent evidence. I’ve always thought that was the intent in these contexts and goes to the reliability of the temperature measurement. The real problem is the melting ice thing happens every year and does little to lend support that average temperatures are rising over time.

    It (the amount of ice as a temperature indicator) makes the bad assumption that ice volume is related to temperature. An example as to why it’s bad: there is likely more ice on your driveway in January than in August but how much depends on precipitation. One would be very hard pressed to show that the amount has anything to do with some global average temperature.

  5. Bruce Foutch

    It just keeps getting better. This just in:

    ‘UN document would give ‘Mother Earth’ same rights as humans’


    I can see it now… “Mr. Briggs. You have been found guilty of crimes against Mother Earth for your callous act of walking off the path in Central Park in June of last year. Your punishment will be commensurate with the size of your carbon footprint as determined by Greenpeace.”

  6. Omedalus

    “People hear that arctic thermometers register an increase and then hear that ice near that thermometer melted.”

    To be fair, seeing secondary evidence that you would expect to correlate with an increasing temperature is, in fact, a useful heuristic by which to establish that your thermometer is still functioning. After all, we need to recognize that our measuring equipment can be flawed. While these secondary phenomena don’t add any evidence that the thermometer itself wouldn’t otherwise provide, it does in fact increase our confidence in the thermometer’s readings in the first place.

  7. mt

    She’s changed her tune from 5 years ago:

    “The consensus is that, with proper attention to sampling and other statistical issues and through the use of scientific inference, studies of observed biological changes can provide rigorous tests of climate-change hypotheses. In particular, independent syntheses of studies worldwide have provided a clear, globally coherent conclusion: Twentieth-century anthropogenic global warming has already affected Earth’s


  8. John M

    Well, I don’t know about the length of puppy dog tails, but since global warming makes fleas last longer…


    And fleas make dogs chase their tails


    Then, ipso facto, global warming causes dogs to chase their tails.

    Of course, it could just be junk food, the other curse of modern living.


  9. obiwankenobi

    “The philosophy of the classroom in one generation will be the philosophy of government in the next.” Abe Lincoln

  10. Omedalus:
    While ‘temperature increase’ can surely melt ice, the same temperature increase can result in increased ice as well.

    Then how is it an intuitive guide which informs us that our thermometers are working?

  11. klem

    “In other words (my words), the risk of falsely asserting a biological change is due to human activity is large. ”

    That fact has never stopped them in the past. Remember climate change is responsilbe for everything today, at least everything bad, if it’s good then something else was the cause. Predictions of the effects of ACC cover just about every situation imaginable now. All angles and events are covered, from volcanic eruptions to teenage acne are now claimed to be caused by climate change. When it rains too much it is climate change, when it is too dry climate change, too warm climate change, too cold climate change, too windy, too calm, too dusty, too clear, everything is due to climate change. The earthquake and tsunami in JApan was caused by ACC, and in a few months the peer reviewed papers will appear to prove it. Virtually every actual climate related event has been predicted and all predictions are therefore found to be correct. This makes the theory of ACC infallible. There are no infallible theories.

    When a theory becomes infallible it ceases being a theory and becomes a faith.

  12. Bob Ludwick

    Climate change comes to VA.

    First background, then data.

    Purple Martins are migratory. They feed on flying insects. No flying insects, no food. Insects fly when the weather is warm; when it is cold, they hunker down in front of the fireplace and wait for warm. Therefore, Martins need warm to eat. Every year, in the process of migrating northward, the Martins send out scouts in front of the main herd to ensure that food will be available as it presses northward.

    There are several organizations of Martin enthusiasts who eagerly await the first spring arrival of the Martin scouts, so that they can report same to Martin Headquarters and get their name on the list of Martin scout sighters and get a gold star, or something. One such individual (who I have never met or corresponded with) lives about four miles from my house and has been reporting on Martin scout arrivals for several years. I know this because I heard that Martins eat carpenter bees, of which, being a log home owner, I have in cubic yard quantities, and went on the internet to get advice on how to get me some Martins. As many as possible. As a byproduct of my search, I learned about the Martin scouts and the scout reporting network.

    Now for data, which is the arrival date in my part of VA for the first observed scouts:

    2007 13 March
    2008 19 March
    2009 24 March
    2010 31 March
    2011 4 April

    What does it mean? Not a clue. But you can bet that if the date sequence were inverted it would be proof positive that not only was the climate changing at a blinding rate but that it was all our fault.

  13. Nomen Nescio

    Unless you consider energy a measure of climate state, in which case the ice melting would be a second piece of evidence. Not only did enough energy come into the climate system to raise the temperature, but also the energy required to melt a quantity of ice also came into the climate.

  14. Roger Drew Williams

    It is one thing (valid scientific process) to perform experiments/collect data to test a hypothesis. It is something altogether different (fraud) to look for data sets which would corroborate a hypothesis whilst knowingly ignoring all evidence which fails to support, or which contradicts, a preordained outcome. When (supposed) scientists are LOOKING for data specifically to validate the AGW theory, the political bias of such a large percentage of the grant-awarding system, would seem to encourage exactly the type of disengenuous behavior that has caused credibility issues with previous data interpretation, ie, ignoring data to fit presupposed outcomes, using mathematical factors unevenly across data sets, falsification of information, disregard of weather stations not fitting desired outcomes, and unfairly weighting evidence (two ready examples are the moving of ALL of CA’s temperature recording stations to coastal areas, which effectively made the Sierra Nevadas a non-entity temperature-wise, and the almost total disregard of all of Northern Canada in collecting temperarure readings to be “averaged” into that nation’s readings). Not only is this a total waste of money, it is being used as justification for the necessity of huge amounts of further government spending and vast new layers of bureaucracy in a country that already has the highest tax rates on business in the world.

Leave a Reply

Your email address will not be published. Required fields are marked *