The balance between ‘Natural Variability’ and ‘Man-Made Impacts’.
Posted by Jeff Id on September 22, 2010
Guest post by Roddy Campbell
Some comments on Judith Curry’s blog post on ‘Doubt’ explored what we know about the causes of ‘Natural Variability’, and hence whether we can predict it based upon that knowledge, or whether the null hypothesis of more of the same is the best and simplest option. Clearly without some assessment of likely natural variability, discerning man’s fingerprint becomes harder.
I have some personal experiences which I think can shed light on this question.
My wife’s moods have considerable natural variability. I am, of course, an ACC adherent, like any right-thinking man, if of a ‘lukecoldist’ persuasion, and I believe that my man-made impacts may well have had a cumulative effect on Gaia (my wife), which may at least in part explain a multi-decadal apparent cooling. The physical side of this is well-understood, most famously in ancient Hindu texts, with later studies in Vienna, and is beyond reasonable argument, although laboratory experiments are difficult as most of us only have one wife. (Apologies, if needed, to all women – I can write only from the husband’s point of view.)
I am however aware, and my therapist has been of use here, that distinguishing my fingerprint from natural variation and natural trends, and being specific about attributing changes in temperature, climate, and extreme weather events to my actions in the Campbell household is not easy. She has suggested that feelings of guilt may be at play here, the allocation of scarce time and resources, and the all-important impact that population explosion can have on the environment.
There is also the question of reliability of data – while I, perhaps through rose-tinted spectacles, recall past winters as being generally much warmer, especially in average night-time temperatures, there is a possibility of Youth Heat Island (YHI) effect, where historic data clearly shows nights as warmer in the past than the present, and extreme night-time events as more frequent. I have been back over the raw data, and if I adjust for YHI (more commonly known as ‘penny-in-the-jar’ syndrome), using adjustment methodology from the peer-reviewed literature (Kinsey et al 1948), it would appear there is considerably less evidence for a statistically significant trend. There is also, of course, the risk of false memory syndrome when extreme events are being recalled.
It is clear that natural variability is a strong cause of swings in household climate, and indeed causes extremely turbulent and stormy conditions from time to time, sometimes accompanied by floods, not to mention the kitchen, where I am often unable to stand the heat and have to stay out.
What causes natural variability, do we understand its causes, and is it predictable? I have to say no, we do not understand, and hence to pretend we can predict on the basis of knowledge is futile; nevertheless there is enough data of a repetitious nature that I am presumptuous enough to assume the null hypothesis; it will continue more or less on the same basis, with cycles of varying lengths from monthly to generational.
Our marriage counsellor, who I know as RC, always seems to have an answer, backed by intensive research, much peer-reviewed literature, and what he likes to call the consensus. Sometimes he seems plausible in his urgent recommendations of mitigation rather than adaptation, and I enjoyed his suggestions of geoengineering, which include the following:
- He suggested that an increased use of aerosols judiciously added to the atmosphere, especially during warmer months, might help.
- He suggested increased solar activity was important, but I have found this expensive, the effects temporary, and the unintended consequences perplexing (the Greek waiter on Rhodes being only the latest example).
- His persistent focus on the need to add more CO0 to the relationship was also useful, as it can persist in the atmosphere for some time, and there definitely was more CO0-ing in the early years.
- While essentially negative on clouds on the horizon, and their effects on feedback, he did say that giving them a silver lining showed promising results.
Sadly he lost me when he insisted that her recent behaviour was unprecedented, as even through my aforementioned rose-tinted glasses I can recall prior climatic conditions in reality equally difficult to adapt to, and impossible to have mitigated. This insistence of his led to a nasty scene, when he said I was unable to see what was obvious – ever-accelerating cooling, which would lead to a runaway ‘Neptune Effect’ on Gaia because of mechanisms of positive feedback. His best forcing examples were clouds which collect over the winter solstice – the ‘in-law’ effect – persisting through to mid-February – the ‘Cupid’ effect – and combining forces to cause climate disruption for the entire first half of the year).
His explanation for my blindness was ideological blinkers, in effect a deep unwillingness to accept that my life as I liked it had irreparably changed, apparently common in middle-aged middle-class men, and that I had changed Gaia through my over-consumption and absurd and unnecessary gas emissions. It was up to me. It was all my fault. That I could not see that, could not accept that natural variation in Gaia was minor compared to my man-made effects, made me feel beyond redemption.
At that point it was clear that he was stating that I was the cause of it all, and that if I wished to rediscover Gaia, and return her to the perfect and gorgeous equilibrium I so well recalled, it was up to me to change, drastically and unilaterally, my behaviour.
I conducted further research, of a paleo nature, in that I spoke to my father-in-law about Gaia’s mother, enquiring as to her nature on a multi-decadal timescale, and her mother also, his mother-in-law, looking for some measure of natural variation and apparent but false trends in the data on a multi-generational basis. He had no idea what I was talking about, and it was clear that, in his wisdom, the possibility of anything other than natural variation, coupled with sensible husbandry, concern for the environment, and eviction of his children from the house to prevent over-population, made no sense at all. When I asked his advice on whether I should, as RC advocated in the strongest possible terms (‘You must act, and act now, there is no time to lose’) make drastic and unilateral changes to my behaviour, he suggested that a round of golf and a couple of hours at the nineteenth hole would benefit both of us.
These suggested changes were clearly not acceptable to me, being very attached to my gas emissions and lifestyle. I also questioned what effect the changes might have, and what unintended consequences might accrue. So I asked Gaia her opinion.
Luckily she felt strongly resentful that the major and over-arching influence on her moods, behaviour, and temperature was being diagnosed as me – in her wilful way she thought it was possible she herself might have something to do with it (which is of course what I’d been telling her all along). She was clear that I was placing too much importance on my behaviour, and told me that I was not, as I seemed to believe under the influence of too much time, therapy, and counselling, the centre of the universe.
So Gaia and I sacked RC, decided that these questions had been asked and wondered about for centuries, and took the decision to adapt, and muddle along as best we can, in a glass half-full kind of way, usually pinot noir.
And I am happy to report that not only have average temperatures started to recover, especially those all important night-time ones, but there is much more CO0 in the atmosphere. I tried to discuss causation and correlation with her, but she told me to shut up.