Merchants of Doubt need to do the math

A feature-length documentary, based on the content of the Merchants of Doubt book by Naomi Oreskes and Erik Conway, went on general release at movie theatres in the USA this weekend. As Desmogbog.com points out, it has already attracted the attention of an odd mixture of ideologically-motivated deniers of the reality of anthropogenic climate disruption. I say “odd” because, as per the above link, those who prefer to see climate science as a conspiracy to raise taxes (and install worldwide Communist government via the united Nations, etc.) include both longstanding disputers of inconvenient science like Fred Singer (who questions whether the movie is defamatory) and self-confessed non-experts like James Delingpole. Both of the above would have done well to watch a recent BBC Four (television) programme – Climate Change by Numbers. In contrast to just about every other programme about climate change that you might have seen, this one is presented by three mathematicians. A 30-second trailer is inserted below but, if you have not seen the full 74-minute programme (opens in a new window), I really would recommend it. https://www.youtube.com/watch?v=cwtJbgH00Cw The programme focuses on three numbers: — 0.85 Celsius – the rise in average global surface temperatures since the 1880s. — 95% – the certainty of the scientific community that this is primarily human-caused. — 1 trillion tonnes – humanity’s carbon budget to avoid 0.85 increasing to 2 Celsius. Along the way, the programme highlights the early work of Svante Arrhenius – who determined that a halving of atmospheric CO2 could cause a 4 Celsius drop in temperature (and therefore that a doubling of CO2 will cause a 4 Celsius rise). With regard to the accuracy of computer models, the programme highlights the way in which this has been proven by their ability to predict the cooling effects of large volcanic eruptions. With regard to our carbon budget, the programme highlights the fact that humanity has already burnt 0.5 trillion tonnes and, unless radical changes are made to global trends, will burn the remaining 0.5 trillion tonnes within 30 years. It also points out that, as ongoing events might well suggest, even 2 Celsius could have severe and pervasive impacts (as the IPCC described them last year). All very inconvenient for libertarians everywhere, I guess. Addendum (17 March 2015): The final third of the programme includes a discussion of ‘extreme value analysis’ (EVA), which Wikipedia helpfully describes as “a branch of statistics… [that] seeks to assess… the probability of events that are more extreme than any previously observed”. Flood defences like the Woolwich Barrier on the Thames estuary were designed using EVA. However, crucially, EVA assumes that average parameter values do not change over time. Therefore, given that climate change invalidates this assumption, it is now accepted that London will need greater protection from flooding in the future. This is why I included a link to (my blog post about) the ‘Climate Departure’ reseach of Mora et al. (i.e. below), which estimates the regional variation in the date by which future climates will have departed from what has hitherto been considered normal. See also: https://anthropocenereality.wordpress.com/2013/11/19/greedy-lying-bar-stewards-guilty-of-crimes-against-humanity/ https://anthropocenereality.wordpress.com/2013/10/11/a-summary-of-the-climate-departure-research-of-mora-et-al/

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About Rick Altman

Possibly just another 'Climate Cassandra' crying 'Wolf' in cyberspace. However, the moral of the old children's story is that the Wolf eventually turned up!
This entry was posted in Climate Science, Cognitive Dissonance, Computer Models, Denial, Environment, Fossil Fuels, IPCC, James Delingpole, Merchants of Doubt, Politics and tagged , , , , , , , . Bookmark the permalink.

5 Responses to Merchants of Doubt need to do the math

  1. Good post, Rick, and one that I will republish over on Learning from Dogs later this week. Well done! Paul

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    • Rick Altman says:

      Thanks, Paul. There is one thing you might care to add (which I forgot to mention), which is this: The final third of the programme includes a discussion of ‘extreme value analysis’ (EVA), which Wikipedia helpfully describes as “a branch of statistics… [that] seeks to assess… the probability of events that are more extreme than any previously observed“. Flood defences like the Woolwich Barrier on the Thames estuary were designed using EVA. However, crucially, EVA assumes that average parameter values do not change over time. Therefore, given that climate change invalidates this assumption, it is now accepted that London will need greater protection from flooding in the future. Athough not explicit in my original post, this was why I included a link to the ‘Climate Departure’ reseach of Mora et al., which estimates the regional variation in the date by which future climates will have departed from what has hitherto been considered normal. Actually, I think I will just amend my original post…

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      • Rick, I’m just preparing tomorrow’s post built around your own. I will add that comment to the post now!

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      • Rick Altman says:

        Or you could just use the amended version of the post (as above)…? Whichever is easiest for you. Many thanks, once again, for bringing this BBC Four programme to the attention of a much wider audience.

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  2. Pingback: And human wisdom? | Learning from Dogs

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