Summary: This is the second post looking at statistician Nassim Nicholas Taleb’s insights about “ruin” risks, and what they tell us about climate change. Here we look at his warning about climate change and two factors he ignores: the duration of the climate risk window and the odds of a climate disaster. The danger is real but the stories that we face certain doom are wild exaggerations, which make rational preparation more difficult. The previous post was Nassim Nicholas Taleb looks at the risks threatening humanity.
Yesterday’s post examined a methodology developed by a team including Nassim Nicholas Taleb for identifying “ruin” risks, where the result is non-recoverable for global civilization — or even the biosphere (described in “Mathematical Foundations for the Precautionary Principle“).
They wrote a note applying their method to one of the major risk debates of our time: “Climate models and precautionary measures” in Science and Technology, in press. The authors are brilliant, and it states with unusual clarity common arguments for radical and immediate action to fight climate change. Here’s the core of their analysis (it’s worth reading in full).
“Those who contend that models make accurate predictions argue for specific policies to stem the foreseen damaging effects; those who doubt their accuracy cite a lack of reliable evidence of harm to warrant policy action. These two alternatives are not exhaustive. One can sidestep the “skepticism” of those who question existing climate-models, by framing risk in the most straight-forward possible terms, at the global scale. That is, we should ask ‘what would the correct policy be if we had no reliable models?’
“We have only one planet. This fact radically constrains the kinds of risks that are appropriate to take at a large-scale. Even a risk with a very low probability becomes unacceptable when it affects all of us –– there is no reversing mistakes of that magnitude.
“…While some amount of pollution is inevitable, high quantities of any pollutant put us at a rapidly increasing risk of destabilizing the climate, a system that is integral to the biosphere. Ergo, we should build down CO2 emissions, even regardless of what climate-models tell us.
“…This leads to the following asymmetry in climate policy. The scale of the effect must be demonstrated tube large enough to have impact. Once this is shown, and it has been, the burden of proof of absence of harm icon those who would deny it.”
Summary: How to deal with risks dominates our headlines, usually driven by single-interest groups that see only their favorite threat. Statistician Nassim Nicholas Taleb’s latest work offers a way to identify the most serious threats facing us, and determine how much we should spend to fight each of them. It has received much attention. Is it useful? Part one of two.
A series of papers by Nassim Nicholas Taleb et al made a large contribution to our understanding of risk: The Precautionary Principle within the statistical and probabilistic structure of “ruin” problems. The main paper is “The Precautionary Principle (with Application to the Genetic Modification of Organisms)“, well-worth reading for anyone interested in GMOs or risk analysis. I will not attempt to summarize it. I will point out one aspect of relevance to many of the key challenges of our time: how should policy-makers allocate funds to prevent or mitigate shockwave threats — potentially disastrous but of low or certain probabilities?
Excerpt: What is a “ruin” scenario, and how should we respond to them?
“We believe that the PP should be evoked only in extreme situations: when the potential harm is systemic (rather than localized) and the consequences can involve total irreversible ruin, such as the extinction of human beings or all life on the planet.
“A ruin problem is one where outcomes of risks have a non-zero probability of resulting in unrecoverable losses. …In biology, an example would be a species that has gone extinct. For nature, ‘ruin’ is ecocide: an irreversible termination of life at some scale, which could be planetwide.
“…Our concern is with public policy. …Policy makers have a responsibility to avoid catastrophic harm for society as a whole; the focus is on the aggregate, not at the level of single individuals, and on global-systemic, not idiosyncratic, harm. This is the domain of collective ‘ruin’ problems.
“…For example, for humanity global devastation cannot be measured on a scale in which harm is proportional to level of devastation. The harm due to complete destruction is not the same as 10 times the destruction of 1/10 of the system. As the percentage of destruction approaches 100%, the assessment of harm diverges to infinity (instead of converging to a particular number) due to the value placed on a future that ceases to exist.
Summary: Journalists live by the rule “if it bleeds, it leads”, sound business advice which buries important good news. Such as the new data from the EIA about US CO2 emissions. It’s another small step away from CAGW, especially the coal-driven RCP8.5 climate nightmare scenario. It’s one of many such during the past few years — with the potential for even better news in the future.
“This is not the end, it is not even the beginning of the end, but it is perhaps the end of the beginning.”
— Speech by Churchill on 10 November 1942 after a key defeat of the Africa Corps by Britain.
“Adjusted for inflation, the economy in 2015 was 15% larger than it was in 2005, but the U.S. energy intensities and carbon intensities have both declined. On a per-dollar of gross domestic product (GDP) basis, in 2015, the United States used 15% less energy per unit of GDP and produced 23% fewer energy-related CO2 emissions per unit of GDP, compared with the energy and emissions per dollar of GDP in 2005.”
The big driver of this change is the shift from coal to natural gas (per the EIA). Coal use peaked in 2008, and declined 32% by 2015 (per the EIA), resulting from the collapse in natural gas prices (fracking!) — predating any effects from the Clean Power Plan.