Saturday, November 29, 2014

Torture of Tornado Data in the United States is Increasing

In the October 17, 2014 issue of Science, Brooks et al publish the claim that tornadoes, while not increasing in frequency, are increasingly “concentrated” among fewer, more intense days. [Ref: H.E. Brooks, G.W. Carbin, P.T.Marsh. Science, 346, 349-352 (2014).] This claim is based on analysis of EF1 or greater tornadoes in the NOAA Severe Weather Database files [Ref: ] for the 60 years 1954 - 2013.

It is well known that increased population and improved doppler weather radar systems has allowed weaker and more remote tornadoes that previously would have gone undetected to be counted. It is also well known that strong EF3+ tornadoes have been declining over this period. So, I suspected that this report of increasingly “concentrated” tornado days, much like the reports of increased rainfall intensity, in the absence of increasing precipitation overall, was an exercise in data torture and failure to recognize biased data. As you will see, I was not disappointed.

Let's begin with the last 60 years of tornado data, collected by year and by intensity on the enhancedFujita scale of EF0-EF5
Figure 1: Annual count of US tornadoes by enhanced Fujita scale classification reveals a sharp rise in the detection of weak tornadoes after 1990.

It is immediately evident that the annual number of recorded US tornadoes is rising, and that this increase appears to be driven by EF0 tornadoes, after 1990. This is not surprising, because 1990-1997 were the years that the national NEXRAD doppler radar network was deployed. [Ref:] To the eye, the EF1 and EF2 numbers do not appear to be biased by a similar sharp increase. But, let's look a little closer. First, we know that weaker tornadoes occur more frequently than stronger tornadoes, but we assume that the ratio of weak to strong tornado frequencies should not change very much over time. This is consistent with the theoretical and observed power law, or 1/f law, governing the relative frequencies of storms of different energies. [Ref: J B Elsner et al 2014 Environ. Res. Lett. 9 024018 ] Therefore we can examine how much more frequently EF0, EF1, and EF2 tornadoes are observed relative to EF3+ tornadoes. While it is very difficult to quantify exactly how much detection bias contaminates the tornado frequency data, we can approximate it by assuming that EF3, 4 and 5 tornadoes are unlikely to have been missed in any of the last six decades.

Figure 2: Frequency of EF0-2 tornadoes in the US relative to EF3+ tornadoes, 1954 – 2013.

Viewed in this way, the contamination of both EF0 and EF1 frequency data by detection bias is clear. In the 1960s and 1970s, EF1 tornadoes were recorded 4-5 times as frequently as EF3+ tornadoes, but since 2000, they have been detected about 8 times as frequently. There is no physical basis for this to be the case, which violates the approximate power law behavior of tornadoes [Ref: J B Elsner et al 2014 Environ. Res. Lett. 9 024018]. It is also clear that the EF2 data is not similarly biased, maintaining a flat frequency that is about 3 times that of the EF3+ tornadoes for the last 60 years, which is consistent with value of 2.8 taken from the observations of Elsner et al.

Brooks et al produced this figure, showing the number of days with EF1+ tornadoes, along with the number of days with over 30 EF1+ tornadoes:

Figure 3: (Brooks et al 2014 Fig. 4) used to claim that EF1+ tornadoes are increasingly clustered.

Using the NOAA source data and the OpenOffice spreadsheet program, I was able to reproduce essentially the same figure:
Figure 4: The number of days with observed EF1+ tornadoes is trending down, but the number of days per year with more than 30 observed EF1+ tornadoes (right side scale) has increased.

If the method of Brooks et al is applied in the same way to EF2+ tornadoes, while accounting for the fact that EF2+ tornadoes are about one-third as frequent, and adjusting the clustering threshold to >10 EF2+ tornadoes per day, figure 5 is obtained:

Figure 5: The number of days per year with observed EF2+ tornadoes is decreasing, but the number of those days with more than 10 observed EF2+ tornadoes (right side scale) remains flat at about 2.7 days per year.

Finally, if we restrict ourselves to the most destructive tornadoes, those of EF3 or greater, it is obvious that the frequency of EF3+ tornadoes in the United States is decreasing, and that there is no increased “clustering” of days with more than three:
Figure 6: Declining frequency of EF3+ tornadoes 1954 – 2013, and number of days with more than three (right side scale).

I was disappointed to see this misleading abuse of statistics reported so uncritically in Science. It is unfortunate that the Science reviewers were not able to see what someone with an undergraduate understanding of statistics should readily see. As demonstrated in the above figures, there is no reason to believe the perceived increase in days with large numbers of tornadoes claimed by Brooks et al is anything other than another artifact of detection bias, because it only applies to weak tornadoes that could have escaped detection in the past, and disappears when restricted to EF2+ or EF3+ tornadoes. This seems to be part of a trend towards credulity by reviewers, and lack of rigor by authors of papers that support public concern about climate change. One never sees this in the medical literature on new cancer treatments, although 30 or 40 years ago, one did.

I understand the frustration of global warming activists who want to be able to claim that destructive weather phenomena, like tornadoes, are becoming worse in some way, when the data says the opposite. Rather than following the data wherever it leads, Brooks et al have chosen to torture the data until it confesses. As the Scottish poet, Andrew Lang said in 1910, "He uses statistics in the same way that a drunk uses a lamp post, for support rather than illumination."

Sunday, June 8, 2014

Anyone who calls carbon dioxide "carbon pollution" is trying to fool you. Part I.

People who use the term "carbon pollution" are dishonest, and deserve your contempt, just as anyone who is trying to deceive you earns your contempt. Ordinary people know what carbon pollution is. It is soot, the black stuff in smoke, or the exhaust of an old diesel engine. It is dirty, and full of cancer-causing polyaromatic hydrocarbons. Responsible producers of energy work hard to minimize the emission of pollution. Since the passage of the Clean Air Act, enormous progress has been made in doing so. Carbon dioxide is none of those things. It is clean, invisible, and essential for life.

Carbon dioxide is the gas we exhale in exchange for oxygen. It is what all plants need to grow. Carbon dioxide is the main raw material that living things use to produce all of our food, our clothing, and even homes, if they are made of wood (cellulose) or cement (limestone). The fact that plants can breathe this trace gas, and use it to grow, despite it being only 0.03 - 0.04% of our atmosphere is nothing short of a miracle. To accomplish this miracle, plants use the energy of the sun to separate the carbon from the oxygen, and build large molecules with it, like cellulose and oils. Animals harvest this energy by recombining the carbon in these large molecules with oxygen to make carbon dioxide.

Fossil fuel is the fossilized remains of plants. So, in a sense, it is fossilized solar energy. When we burn fossil fuels, we release that energy, and return the carbon dioxide to the atmosphere. If we are responsible, we do our best to minimize the dirty parts of burning fuel, like soot, and sulphates, and release mostly clean, odorless, colorless carbon dioxide.

You are by necessity very familiar with the feedback mechanism that keeps the right amount of carbon dioxide dissolved in your body. It is called breathing. If you breathe too slowly, or hold your breath, dissolved carbon dioxide builds up in your body. That creates the urge to breathe. Breathing blows out carbon dioxide. If you intentionally hyperventilate, then your body loses too much carbon dioxide, the pH of your blood gets too high, your urge to breathe decreases, you feel numbness and tingly around your lips, hands, and feet, lightheaded, and you might even pass out. The speed of your breathing is constantly regulating the amount of carbon dioxide in your body, through negative feedback, so that it stays close to the right amount, not too much, not too little. To stay healthy, you need about 1,400 times as much carbon dioxide dissolved in your body as there is in the same volume of air around you. Even though oxygen is the main thing we need to get from the air, it is little more than a bystander in the process of regulating our breathing under ordinary conditions.

The fact that we need a fair amount of carbon dioxide in our bodies to survive is a clue that it is not pollution, any more than water is pollution. Sure, you can have too much of it, just as you can drown in too much water, but it can't be called pollution.

Yet, the political newspeak of our time has adopted the term "carbon pollution" to refer to carbon dioxide. This debasement of language is intended to muddy your understanding of carbon dioxide, and make you think of it as something dirty. As readers of George Orwell's 1984 know, it is the job of politics to debase the language. That's how the people get fooled, and harmful policies that benefit only a select few get passed. If language loses its meaning, we lose our ability to communicate and evaluate ideas. It is your job to see through that debasement, and push back.

They want you to believe that a global catastrophe will result from carbon dioxide rising much beyond its current level. When you ask them why, they talk about climate models. When you ask them how well the climate models have done prospectively modeling the climate, they will tell you, not very well, but since we are very unsure of the future, we should be cautious and not raise carbon dioxide much above recent levels. The term "carbon pollution" is also a kind of social signaling among those who would like to force a reduction in the use of fossil fuels. It is one of their gang signs.
Since the beginning of the industrial age, the burning of fossil fuels, and to a lesser extent the outgassing of warming seas recovering from the Little Ice Age, have caused carbon dioxide to be returned to the atmosphere faster than it is absorbed from it.

There are legitimate questions to be asked about the effects of rising carbon dioxide in our atmosphere. The best and most well known record of atmospheric carbon dioxide comes from the observatory at Mauna Loa, called the Keeling curve, after the late Prof. Charles David Keeling, of UCSD, who supervised the initial work of the observatory in 1958. In March 1958, the level was 316 ppm, and in March 2014 it was 400 ppm, a 26.6% increase. That is a significant amount, and potentially a cause for concern. People with a sincere interest in addressing this concern do not debase the meaning of words, because that undermines the clarity needed for serious investigation.

(to be continued in Part II)

Saturday, April 5, 2014

The new Captain America movie is an allegory for our time.

I saw the new Captain America movie with my daughter last night. I liked it much more than I expected, in part because it explores themes that are currently in the headlines, and in my social media feed. I had feared the movie would be an exercise in jingoistic flag-waving as the super-human embodiment of American values and virtues battles evil alien forces. Instead, it is a thoughtful exploration of the eternal questions of liberty versus security, trust versus suspicion, and obedience versus resistance. Also, Scarlett Johanssen gets lots of screen time. (Caution: moderate spoilers ahead.) The movie centers on a plan to impose peace and order on the world through an algorithm that analyzes a person's propensity to cause problems for society, or for the government, by processing the entirety of the world's digital traffic, public and private. Those people are then killed using a new technology that there is no need to reveal here. It is calculated that by eliminating just 20 million people, life for the remaining 7 billion will be orderly and peaceful. The phrase "final solution" might come to mind.

Meanwhile, in the headlines, we read the ongoing revelations from Edward Snowden's whistleblowing of the NSA, the utilization of the IRS to target politically unfavored groups for "special scrutiny", the latest Supreme Court decision (McCutcheon v FEC) overturning the aggregate limits on contributions to multiple campaigns, and most recently, the forcing out of Mozilla's CEO.

Brendan Eich, the Mozilla co-founder, and inventor of Javascript, was forced out of his recent CEO appointment because of a $1,000 contribution he made on behalf of California's 2008 Proposition 8, opposing same-sex marriage. As far as we know, Mr. Eich did not say or do anything in any of his roles at Mozilla, including CEO, that could be construed as anti-gay. He affirmed his support of Mozilla's very liberal health benefits for same-sex partners, and expressed no interest in treating LGBT people any differently with respect to hiring, promotions, or benefits. Outside of this one campaign donation in 2008, he seemed the very model of a modern liberal CEO.

(Ironically, in 2008, presidential candidate Senator Barack Obama, gave far more support to California's Proposition 8 than did Mr. Eich, directly by making his opposition to same-sex marriage part of his presidential campaign, and indirectly by organizing a very effective get-out-the-vote campaign in communities that were far more hostile to gay marriage than was the average Californian. I have yet to see an organized campaign from the opponents of Proposition 8 to hound him out of office for it.)

Furthermore, Proposition 8 was dead, and rightfully so. After winning in California's election booths in 2008 by 52% to 48%, the law was ruled unconstitutional in a California court in 2010, and the United States Supreme Court chose to let that ruling stand in 2013. Nevertheless, somebody saw fit to comb the records of that now dead campaign, discover Brendan Eich's contribution there, and target him to be purged. In light of this, the campaign to oust Eich seems much more like a vindictive exercise of power than a defense of civil rights too long denied.

In Captain America: The Winter Soldier, one of the villians attempts to stop Natasha Romanov by asking her if she is prepared to have her dark past exposed on the Internet.

This new algorithm for analyzing the digital record, using it to identify "problem people", and targeting them to be purged from their jobs, their careers, their schools, or their homes, should have us all concerned. You will increasingly be judged by your life's worst moments, or the moments that can be cast in the most negative light. Everyone is now subject to career-ending character assassination at all times. Even if the accusations are false, it does not matter. Mark Twain's lie that once got halfway around the world while the truth was pulling on its shoes, now goes around the world thousands of times, spawns memes, reaction vlog videos, and outraged articles in the Huffington Post, in the same time.

At the same time that our lives are increasingly exposed to digital inspection, the explosion of the regulatory state means that we are all guilty of some violation, or as Harvey Silverglate writes, we commit on average "Three Felonies a Day." The job of law enforcement is less one of bringing justice to those who break the law, and more one of selecting whom to prosecute. Those with unpopular opinions, or unpopular occupations, of course. The prosecutions that will get you elected mayor, or governor. Right, Mr. Guliani? Right, Mr. Spitzer?

In reference to the Mozilla affair, a friend of mine who immigrated to the US from the Soviet Union recently observed, "There is no freedom of speech, except for those with nothing to lose." If that is true, then free, democratic society is doomed. It is the precise opposite of the principle of "skin in the game," advocated by Nassim Nicholas Taleb as a guiding ethical heuristic to reduce catastrophic outcomes. If the only voices we empower are the ones who pay no price for being wrong, we are sure to go wrong very quickly.

What will life be like under this new constant threat of being purged? Should we accept it as the new normal? Will there be a mechanism to purchase indulgences that protect you from being targeted? Can the American values that worked in the pre-digital age survive Total Information Awareness?

A free, tolerant, pluralistic, democratic republic can only survive if we can live and work side-by-side with people who have very different ideas than we do about how to live. Live and let live is the rule of a civil society. People who fancy themselves as champions of "diversity" might imagine that a generalization of draconian campus speech codes to society at large will promote harmony. However, it is becoming more plain that what it promotes is witch hunts.

Our culture is changing. People have so much choice in their sources of information, entertainment, and recreation that they consciously or unconsciously silo themselves in comfortable echo chambers of like-minded people. It does not help that the recent economic downturn also makes people feel squeezed and insecure. Opinions are hardened and people more socially retrenched. Decreasingly able or willing to engage with challenging views, we become more tribal. Our gang signs are the things we "like", the words we use.

In this new culture, the first approach to disagreement is to silence the opposing view. Social media facilitates this, while at the same time being a gain medium for comforting lies and half-truths that are shared at internet speed, and that serve to further polarize opinion. Why try to understand why someone seems to harbor such horrible opinions when it is easier to "unfriend" them?

It will take an ever-increasing amount of effort to find and engage people of divergent views with humility and respect, but it might be the most import social activity there is. Charles Murray, in "Coming Apart", has written eloquently about how small minority of people who make the major political, economic, and cultural decisions in our society are becoming more and more isolated from the vast majority of people who have to live with the consequence of those decisions. They have less and less "skin in the game". This is a trend that can only end in catastrophe.

The theme of the Avengers movies is that each super hero has their own special abilities, but also bears the physical and psychological scars of their past. None of us are perfect, and all of us are a little broken. The guy that invented Javascript also voted against marriage equality. If we judge each other by our worst moments, we will never get the good stuff.