AGW in Austin? (II)

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I said this in “AGW in Austin?“:

There’s a rise in temperatures [in Austin] between the 1850s and the early 1890s, consistent with the gradual warming that followed the Little Ice Age. The gap between the early 1890s and mid-19naughts seems to have been marked by lower temperatures. It’s possible to find several mini-trends between the mid-19naughts and 1977, but the most obvious “trend” is a flat line for the entire period….

Following the sudden jump between 1977 and 1980, the “trend” remains almost flat through 1997, albeit at a slightly higher level….

The sharpest upward trend really began after the very strong (and naturally warming) El Niño of 1997-1998….

Oh, wait! It turns out that Austin’s sort-of hot-spell from 1998 to the present coincides with the “pause” in global warming….

The rapid increase in Austin’s population since 2000 probably has caused an acceleration of the urban heat-island (UHI) effect. This is known to inflate city temperatures above those in the surrounding countryside by several degrees.

What about drought? In Austin, the drought of recent years is far less severe than the drought of the 1950s, but temperatures have risen more in recent years than they did in the 1950s….

Why? Because Austin’s population is now six times greater than it was in the 1950s. The UHI effect has magnified the drought effect.

Conclusion: Austin’s recent hot weather has nothing to do with AGW.

Now, I’ll quantify the relationship between temperature, precipitation, and population. Here are a few notes about the analysis:

  • I have annual population estimates for Austin from 1960 to the present. However, to tilt the scale in favor of AGW, I used values for 1968-2015, because the average temperature in 1968 was the lowest recorded since 1924.
  • I reduced the official population figures for 1998-2015 to reflect a major annexation in 1998 that significantly increased Austin’s population. The statistical effect of that adjustment is to reduce the apparent effect of population on temperature — thus further tilting the scale in favor of AGW.
  • The official National Weather Service station moved from Mueller Airport (near I-35) to Camp Mabry (near Texas Loop 1) in 1999. I ran the regression for 1968-2015 with a dummy variable for location, but that variable is statistically insignificant.

Here’s the regression equation for 1968-2015:

T = -0.049R + 5.57E-06P + 67.8

Where,

T = average annual temperature (degrees Fahrenheit)

R = annual precipitation (inches)

P = mid-year population (adjusted, as discussed above)

The r-squared of the equation is 0.538, which is considerably better than the r-squared for a simple time trend (see the first graph below). Also, the standard error is 1.01 degrees; F = 2.96E-08; and the p-values on the variables and intercept are highly significant at 0.00313, 2.19E-08, and 7.34E-55, respectively.

Here’s a graph of actual vs. predicted temperatures:

Actual vs predicted average annual temperatures in Austin

The residuals are randomly distributed with respect to time and the estimated values of T, so there’s no question (in my mind) about having omitted a significant variable:

Average annual temperatures_residuals vs. year

Average annual temperaturs_residuals vs. estimates of T

Austin’s average annual temperature rose by 3.6 degrees F between 1968 and 2015, that is, from 66.2 degrees to 69.8 degrees. According to the regression equation, the rise in Austin’s population from 234,000 in 1968 to 853,000 (adjusted) in 2015 accounts for essentially all of the increase — 3.5 degrees of it, to be precise. That’s well within the range of urban heat-island effects for big cities, and it’s obvious that Austin became a big city between 1968 and 2015. It also agrees with the estimated effect of Austin’s population increase, as derived from the equation for North American cities in T.R. Oke’s “City Size and the Urban Heat Island.” The equation (simplified for ease of reproduction) is

T’ = 2.96 log P – 6.41

Where,

T’ = change in temperature, degrees C

P = population, holding area constant

The author reports r-squared = 0.92 and SE = 0.7 degrees C (1.26 degrees F).

The estimated UHI effect of Austin’s population growth from 1968 to 2015 is 2.99 degrees F. Given the standard error of the estimate, the estimate of 2.99 degrees isn’t significantly different from my estimate of 3.5 degrees or from the actual increase of 3.6 degrees.

I therefore dismiss the possibility that population is a proxy for the effects of CO2 emissions, which — if they significantly affect temperature (a big “if”) — do so because of their prevalence in the atmosphere, not because of their concentration in particular areas. And Austin’s hottest years occurred during the “pause” in global warming after 1998. There was no “pause” in Austin because its population continued to grow rapidly; thus:

12-month average temperatures in Austin_1903-2016

Bottom line: Austin’s temperature can be accounted for by precipitation and population. AGW will have to find another place in which to work its evil magic.

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Related reading:
U.S. climate page at WUWT
Articles about UHI at WUWT
David Evans, “There Is No Evidence,” Science Speak, June 16, 2009
Roy W. Spencer, “Global Urban Heat Island Effect Study – An Update,” WUWT, March 10, 2010
David M.W. Evans, “The Skeptic’s Case,” Science Speak, August 16, 2012
Anthony Watts, “UHI – Worse Than We Thought?,” WUWT, August 20, 2014
Christopher Monckton of Brenchley, “The Great Pause Lengthens Again,” WUWT, January 3, 2015
Anthony Watts, “Two New Papers Suggest Solar Activity Is a ‘Climate Pacemaker‘,” WUWT, January 9, 2015
John Hinderaker, “Was 2014 Really the Warmest Year Ever?,” PowerLine, January 16, 2015
Roy W. Spencer, John R. Christy, and William D. Braswell, “Version 6.0 of the UAH Temperature Dataset Released: New LT Trend = +0.11 C/decade,” DrRoySpencer.com, April 28, 2015
Bob Tisdale, “New UAH Lower Troposphere Temperature Data Show No Global Warming for More Than 18 Years,” WUWT, April 29, 2015
Patrick J. Michaels and Charles C. Knappenberger, “You Ought to Have a Look: Science Round Up—Less Warming, Little Ice Melt, Lack of Imagination,” Cato at Liberty, May 1, 2015
Mike Brakey, “151 Degrees Of Fudging…Energy Physicist Unveils NOAA’s “Massive Rewrite” Of Maine Climate History,” NoTricksZone, May 2, 2015 (see also David Archibald, “A Prediction Coming True?,” WUWT, May 4, 2015)
Christopher Monckton of Brenchley, “El Niño Has Not Yet Paused the Pause,” WUWT, May 4, 2015
Anthony J. Sadar and JoAnn Truchan, “Saul Alinsky, Climate Scientist,” American Thinker, May 4, 2015
Clyde Spencer, “Anthropogenic Global Warming and Its Causes,” WUWT, May 5, 2015
Roy W. Spencer, “Nearly 3,500 Days since Major Hurricane Strike … Despite Record CO2,” DrRoySpencer.com, May 8, 2015

Related posts:
AGW: The Death Knell (with many links to related readings and earlier posts)
Not-So-Random Thoughts (XIV) (second item)
AGW in Austin?
Understanding Probability: Pascal’s Wager and Catastrophic Global Warming
The Precautionary Principle and Pascal’s Wager

The Precautionary Principle and Pascal’s Wager

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Reduced to its essence, the precautionary principle (PP) is this: Avert calamity regardless of the cost of doing so.

The thinking person, as opposed the the extreme environmentalist or global-warming zealot, will immediately and carefully pose these questions about the PP: What, specifically, is the calamity to be averted? How might it be averted? With what degree of certainty? What are the opportunity and monetary costs of the options?

Take death, for example. Most persons who are in good health (and even many who are in declining health) consider death to be a calamity. So, too, do their loved ones (usually). How, then, might death be averted, with what degree of certainty, and at what cost?

Death can be averted only temporarily. That is, death often can sometimes be postponed, but never defeated. So the question is how can it be postponed, and at what cost. Let’s take an extreme case of a man dying of a virulent cancer (confirmed by extensive tests and procedures) for which there is no known treatment, other than palliative care. What good will it do that man (or his heirs) to spend his fortune in search of cure for his disease? He will almost certainly die before a possible cure is identified and can be supplied to him. But in funding the search for a cure he would have followed the PP by doing his utmost to avoid the calamity of death, without regard for the calamity thereby visited upon upon his heirs.

In sum, the PP shouldn’t be followed in cases where:

  • there is nothing that human beings can do to avert the calamity, or
  • the cost of ameliorating the calamity is itself calamitous.

Extreme environmentalists and global-warming zealots are guilty of sub-optimizing. They focus on particular calamities, not on the big picture of human flourishing. Take global warming. It has been said many times that warming has many advantages, such as a longer growing season and a lower death rate (cold is a bigger killer than heat). It has also been shown that warming hasn’t been occurring as fast as projected. The over-estimation of warming is probably due to (a) overstatement of the effects of CO2 emissions on temperatures and (b) inadequate modeling that omits key factors. But the zealots remain undeterred by such considerations.

The only thing that’s saving humanity from total impoverishment at the hands of global-warming zealots is the ridiculously high cost of (probably futile) efforts to combat global warming. Shutting down coal mines is bad enough, though tolerable given the advances that have been made in the extraction of natural gas and oil. But there is little taste (except among well-fed elites) for shutting down factories, forcing everyone to drive battery-powered cars, shifting to high-cost and unreliable sources of energy (solar, wind, and hydro), forcing people to live in densely populated cities, and so on. And if all of those things were to happen, what difference would it make? Almost none.

Moreover, there is nothing unusual about the rising temperatures of recent decades, neither in rapidity nor level. As Bob Tisdale observes, during three global warming periods — 1916-1946, 1964-1993, and 1986-2015 —

there were similar observed changes in global surface temperatures. It’s tough to claim that the recent global warming is unprecedented when surface temperatures rose at a comparable rate over a 30-year timespan that ended about 70 years ago.

Second, climate models are not simulating climate as it existed in the past or present.  The model mean of the climate models produced for the IPCC’s 5th Assessment Report simulates observed warming trends for one of the three periods shown in this post. Specifically, during the three global warming periods discussed in this post, climate models simulated three very different rates of warming (+0.050 deg C/decade for 1916-1946, +0.155 deg C/decade for 1964-1993, and +0.255 deg C/decade for 1986-2015), yet the data from GISS indicated the warming trends were very similar at +0.16 deg C/decade and +0.166 deg C/decade. If climate models can’t simulate global surface temperatures in the past or present, why should anyone have any confidence in their prognostications of future surface temperatures?

Third, the models’ failure to simulate the rate of the observed early 20th Century warming from 1916-1945 indicates that there are naturally occurring processes that can cause global surfaces to warm over multi-decadal periods above and beyond the computer-simulated warming from the forcings used to drive the climate models [emphasis added].  That of course raises the question, how much of the recent warming is also natural?

Fourth, for the most-recent 30-year period (1986-2015), climate models are overestimating the warming by a noticeable amount. This, along with their failure to simulate warming from 1916-1945, suggests climate models are too sensitive to greenhouse gases and that their projections of future global warming are too high.

Fifth, logically, the fact that the models seem to simulate the correct global-warming rate for one of the three periods discussed [1964-1993] does not mean the climate models are performing properly during the one “good” period.

Despite such reasonableness, global-warming-zealot proponents of the PP are not to be deflected. For theirs is a religion, which seems to take Pascal’s wager seriously. Here’s Robert Tracinski on the subject:

Do you freaking love science? Then you might be a big enough sucker to fall for a claim like this one: “Across the span of their lives, the average American is more than five times likelier to die during a human-extinction event than in a car crash.” Which was actually made by an environmentalist group called the Global Challenges Foundation and reported with a straight face in The Atlantic….

There is something that sounded familiar to me about this argument, and I realized that it borrows the basic form of Pascal’s Wager, an old and spectacularly unconvincing argument for belief in God. (Go here if you want to give the idea more thought than it probably deserves.) Blaise Pascal’s argument was that even if the existence of God is only a very small probability, the consequences are so spectacularly huge — eternal life if you follow the rules, eternal punishment if you don’t — that it makes even a very small probability seem overwhelmingly important. In effect, Pascal realized that you can make anything look big if you multiply it by infinity. Similarly, this new environmentalist argument assumes that you can make anything look big if you multiply it by extinction….

If Pascal’s probabilistic argument works for Christianity, then it also works for Islam, or for secular versions like Roko’s Basilisk. (And yes, an “all-seeing artificial intelligence” is included in this report as a catastrophic possibility, which gives you an idea of how seriously you should take it.) Or it works for global warming, which is exactly how it’s being used here.

Pascal was a great mathematician, but this was an awful abuse of the nascent science of probabilities. (I suspect it’s no great shakes from a religious perspective, either.) First of all, a “probability” is not just anything that you sort of think might happen. Imagination and speculation are not probability. In any mathematical or scientific sense of the word, a probability is something for which you have a real basis to measure its likelihood. Saying you are “95 percent certain” about a scientific theory, as global warming alarmists are apt to do, might make for an eye-catching turn of phrase in press headlines. But it is not an actual number that measures something.

Indeed.

Tracinski later hits a verbal home run with this:

This kind of Pascal’s-Wager-for-global-warming is part of a larger environmentalist program: a perverse attempt to take our sense of the actual risks and benefits for human life and turn it upside down.

If we’re concerned about the actual dangers to human life, we don’t have to assume a bunch of bizarre probabilities. The big dangers are known quantities: poverty, squalor, disease, famine, dictatorship, war. And the solutions are also known quantities: technology, industrialization, economic growth, freedom.

Global-warming zealots are usually leftists, and leftists claim to be upholders of science. Yet they cling to two anti-scientific dogmas: the precautionary principle and Pascal’s Wager. As Tracinski says, “global warming has become a religion with a veneer of science.”

Understanding Probability: Pascal’s Wager and Catastrophic Global Warming

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I love it when someone issues a well-constructed argument that supports my position on an issue. (It happens often, of course.) The latest case in point is a post by Robert Tracinski, “Pascal’s Wager for the Global Warming Religion” (The Federalist, May 3, 2016). Tracinski address this claim by some global-warming zealots:

Across the span of their lives, the average American is more than five times likelier to die during a human-extinction event than in a car crash.

There’s a lot more wrong with that statement than the egregious use of plural (“their lives”) and singular (“is”) constructions with respect to “the average American” (singular). Here’s what’s really wrong, in Tracinski’s words:

There is something that sounded familiar to me about this argument, and I realized that it borrows the basic form of Pascal’s Wager, an old and spectacularly unconvincing argument for belief in God. (Go here if you want to give the idea more thought than it probably deserves.) Blaise Pascal’s argument was that even if the existence of God is only a very small probability, the consequences are so spectacularly huge — eternal life if you follow the rules, eternal punishment if you don’t — that it makes even a very small probability seem overwhelmingly important. In effect, Pascal realized that you can make anything look big if you multiply it by infinity. Similarly, this new environmentalist argument assumes that you can make anything look big if you multiply it by extinction….

If Pascal’s probabilistic argument works for Christianity, then it also works for Islam, or for secular versions like Roko’s Basilisk. (And yes, an “all-seeing artificial intelligence” is included in this report as a catastrophic possibility, which gives you an idea of how seriously you should take it.) Or it works for global warming, which is exactly how it’s being used here.

Pascal was a great mathematician, but this was an awful abuse of the nascent science of probabilities. (I suspect it’s no great shakes from a religious perspective, either.) First of all, a “probability” is not just anything that you sort of think might happen. Imagination and speculation are not probability. In any mathematical or scientific sense of the word, a probability is something for which you have a real basis to measure its likelihood. Saying you are “95 percent certain” about a scientific theory, as global warming alarmists are apt to do, might make for an eye-catching turn of phrase in press headlines. But it is not an actual number that measures something.

Indeed.

Tracinski later hits a verbal home run with this:

This kind of Pascal’s-Wager-for-global-warming is part of a larger environmentalist program: a perverse attempt to take our sense of the actual risks and benefits for human life and turn it upside down.

If we’re concerned about the actual dangers to human life, we don’t have to assume a bunch of bizarre probabilities. The big dangers are known quantities: poverty, squalor, disease, famine, dictatorship, war. And the solutions are also known quantities: technology, industrialization, economic growth, freedom.

Repeat after me:

A probability is a statement about a very large number of like events, each of which has an unpredictable (random) outcome. Probability, properly understood, says nothing about the outcome of an individual event. It certainly says nothing about what will happen next.

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Related posts:

Pascal’s Wager, Morality, and the State

Some Thoughts about Probability

My War on the Misuse of Probability