The Signal, The Noise and Climate Change

8 May 2014

“Nate Silver is probably the world’s only rock-star statistician”, says The Economist. [i] But Silver earned his acclaim through some remarkably accurate forecasts. His remarkably accurate forecasts result from some very careful thinking about the nature of information and its communication.

In essence, there are two problems: First, the amount of raw data being generated each day is enormous and growing, likely exponentially — a torrent of data, most of which is meaningless noise, from which a meaningful signal needs be gleaned. Second, that signal must be interpreted and contextualized as useful information. Statistics provides powerful tools for separating signal from noise. The interpretation and contextualization bits, however, require very human intervention.

Recently, the U.N. Intergovernmental Panel on Climate Change (IPCC) released a detailed set of findings on the potential future effects of Climate Change. As I write this, the U.S. government released its third National Climate Assessment, which itemizes specific climate risks in this country. So, the matter of Climate Change and its effects are much in the news, with the interpretation and contextualization that “in the news” conveys.

Here is another look at Nate Silver’s take on Climate Change. I still find it both comprehensible and remarkably dispassionate.

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Nate Silver, Forecasting and Climate Change

From 21 March 2013

Since the beginning of President Obama’s second term, Climate Change has re-emerged as a major policy issue. As an issue, Climate Change remains politically polarized. One side sees Climate Change as a dire emergency, resulting primarily from human activities, which requires immediate and extensive (and expensive) remedial actions. The other side regards Climate Change as, at worst, a natural phenomenon, about which, like the weather, there is little to be done.

Much of the public discourse on Climate Change is based in partisan or ideological positions. I was pleased to find a comprehensible, dispassionate view by Nate Silver that might be useful to anyone whose mind isn’t completely closed. Nate Silver is a statistician and a forecaster who has become one of Time magazine’s 100 most influential people, most notably for his work on forecasting the future success of professional baseball prospects and his almost unbelievably accurate forecasts of the 2008 and 2012 national elections.

Silver’s book, The Signal and the Noise,[ii] discusses the world of statistically – based prediction in a clear, engaging and useful manner. It certainly is not a textbook on statistics. Chapter 12 of Silver’s book, titled A Climate of Healthy Skepticism, addresses Climate Change. Silver proposes that “We should examine the evidence and articulate what might be thought of as a healthy skepticism toward climate predictions. As you will see, this kind of skepticism does not resemble the type that is common in blogs or in political arguments over global warming.” Silver does as he proposes.

Silver distinguishes among Greenhouse Effect, Global Warming and Climate Change, three terms that are often used interchangeably in common discourse. Silver’s findings and comments on each of these are of the essence:

The Greenhouse Effect >> Silver agrees with the International Panel on Climate Change [iii]  that “There is a natural greenhouse effect that keeps the Earth warmer than it would otherwise be”. The greenhouse effect is due to concentrations of certain atmospheric gases, especially water vapor and CO2. Silver points out that the Greenhouse Effect was first demonstrated in the laboratory over 150 years ago.

Global Warming >> Silver also agrees with IPCC that: (a) the concentration of greenhouse gases (especially CO2) in the atmosphere are increasing; (b) that increases in the concentration of greenhouse gases in the atmosphere can result in increases in the average temperature of the Earth’s surface; and (c) that the concentration of water vapor in the atmosphere can increase as the temperature of the atmosphere increases. Part (a) of this statement reflects actual measurements over the period 1959 – today. Part (b) rests on laboratory demonstration. Part (c) is a fundamental principle of weather science.

Returning to part (a): Silver also notes that the observed increase in the concentration of CO2 in the atmosphere can be largely attributed to human activity, especially widespread combustion of fossil fuels, of which CO2 is a primary by-product. This Silver accepts as “a matter of simple observation”.

Global Temperature ChartSilver also examines the actual data on global temperature trends, where he finds an increase of about 0.8o C over the course of the 20th century, with more than half of that increase occurring over the years 1975 – 2000. Since the concentration of CO2 in the atmosphere is measurably increasing, the rate of temperature increase might reasonably be expected to be increasing. So, taking the apparent rate of temperature increase over the last quarter (1975 – 2000) — about 2.0o C per century — as a basis for extrapolation might seem reasonable. Except for the inconvenient fact that the global temperature did not raise at all — nada — in the first decade of this century (2000 – 2010). As everyone who has studied statistical techniques like SQC or SPC knows, it is important to be careful with sampling and sample sizes.

Climate Change >> The existence of the Greenhouse Effect, the observation that the average global temperature demonstrates an increasing trend, and the general correlation of CO2 concentration in the atmosphere with increasing temperature are all, in my view, readily verifiable and beyond reasonable dispute. The term Climate Change, however, refers to a matter of prediction — a matter of future effects rather than of present causes. Prediction of these effects relies on computer models of the behavior of the global climate. And the global climate is a large, complex and dynamic system. Large, complex and dynamic systems can be expected to respond to changes in a non-linear manner. Realistically, modeling global climate as a system is not a simple matter. Silver points out several areas where a healthy skepticism is entirely appropriate.

At best, well constructed computer models might be expected to predict general trends over sufficiently long periods of time. Regardless of how large the effects of global warming may prove to be, computer models cannot be expected to predict the specific character, magnitude, timing of these effects with sufficient confidence to realistically act on them [iv] .

What This Means for Smaller Manufacturers:

Recently, the President asked Congress to pass legislation to substantially reduce emissions of “greenhouse gases”, principally carbon dioxide (CO2) from the combustion of fossil fuels. The President also stated that he would take administrative actions, in the (likely) event that legislation acceptable to the President not be enacted. Either way — through legislation or by administrative actions (through EPA and other channels) — almost all manufacturers will be increasingly affected by the direct or collateral consequences of reducing CO2 emissions.

Happily, reducing CO2 emissions means reducing energy consumption by improving energy utilization efficiency. And reducing energy consumption reduces costs. So, don’t argue about whether Global Warming and Climate Change are real or not. Instead, focus on reducing your energy consumption.

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Jera LogoThoughtful comments and experience reports are always appreciated.

…  Chuck Harrington (Chuck@JeraSustainableDevelopment.com)

P.S: Contact me when your organization is serious about pursuing Sustainability … CH

This blog and associated website (www.JeraSustainableDevelopment.com) are intended as a resource for smaller manufacturers in the pursuit of Sustainability. While editorial focus is on smaller manufacturers, all interested readers are welcome. New blog posts are published on Wednesday evenings.


 [i] The Economist, May 3rd – 9th issue, page 50

 

[ii] Silver, Nate, The Signal and The Noise, Penguin Press, New York (2012), especially Chapter12:  A Climate of Healthy Skepticism, pages 370 – 411

 

[iii] From the First Assessment Report of the United Nations’ International Panel on Climate Change, issued in 1990.

 

[iv] This last statement is, in part, paraphrased from comments by Professor John Steinbruner at the World Affairs Council Summit on Climate Change earlier this month (March 2013), as reported in Top Ten Effects of Global Warming on Business (www.triplepundit.com/2013/03/top-ten-effects-global-warming-business/). The article is timely and worth reading. I have no idea where the 6.0o C projection comes from.