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: http://www.spc.noaa.gov/wcm/#data ] 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: http://en.wikipedia.org/wiki/NEXRAD#Deployment] 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 http://iopscience.iop.org/1748-9326/9/2/024018/article ] 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."

Climate Alarmist Bingo

How to play: If you are ever caught in a room where a climatist is droning on about the doom that is sure to come if we don't stop burning fossil fuels, take out this handy bingo card. Climate Alarmist Bingo (TM) turns an otherwise tedious situation into fun for you and your friends. Check off each square as it is mentioned. Shout "BINGO!" the moment a vertical, horizontal, or diagonal row of 5 is completed. If you want to shout a different two-syllable B word, well, who am I to tell you what to do?

It randomly regenerates with each reload of the page. There are 11,420,609,241,913,781,691,285,504,000,000 different cards!

Wait! Wait! Looks like we're coming in to some more turbulence!

Credit: Gary Larson, "The Far Side"

Fasten your seat belts. If your peanuts scatter and your coffee spills and heavy baggage threatens to burst from the overhead compartment while you jet across "the pond" between the US and Britain, you now have permission to blame anthropogenic climate change. According to simulations of a doubled carbon dioxide concentration carried out by Paul D. Williams and Manoj M. Joshi, of the Universities of Reading and East Anglia, respectively, and published in the April 8, 2013 issue of Nature Climate Change, average turbulence along transatlantic is projected to increase 10 - 40 percent, and the incidence of moderate to severe turbulence 40 - 170 percent. They write, "Our results suggest that climate change will lead to bumpier transatlantic flights by the middle of this century. Journey times may lengthen and fuel consumption and emissions may increase."

Unlike the turbulence associated with storms, landforms, and aircraft wakes, clear air turbulence (CAT) is notoriously difficult to detect in advance, offering little in the way of a radar signature, and little warning for pilots. Injuries are rare, and affect almost exclusively unbuckled passengers and crew.

Over the North Atlantic, the conditions that favor clear air turbulence are the eddies that form along the edges of a the jet stream. Williams and Joshi predict that the jet stream will become stronger, and move northward to affect more of the transatlantic air traffic. Their predictions are entirely model-based. Some historical measurements of the conditions that favor turbulence over the North Atlantic since 1980, during which time carbon dioxide has increased about 15%, have increased over the North Atlantic, but decreased over the Pacific. Historical conditions that favor turbulence do not correlate as well with carbon dioxide as with the North Atlantic Oscillation, according to a 2007 study by Jaeger and Sprenger in JGR. They concluded, "The interannual variability of CAT is significant as indicated by the CAT indicators and can be correlated with the two phases of the North Atlantic Oscillation as well as with the Pacific/North American flow pattern. The interannual variations of the TI and PV patterns are consistent with the variation of the jet position associated with the NAO, whereas the Ri and, especially, the N2 patterns are not markedly influenced by the jet stream position. During positive phases of the NAO, generally larger turbulence frequencies occur, which might be due to stronger jets, and associated with that, more frequent instabilities."

Williams and Joshi make no mention of the North Atlantic Oscillation in their report. It is a part of our climate, but not a part of their model simulation. Perhaps the rise in carbon dioxide will cause more turbulence for flight simulators than for actual flights. It is all part of the rush to supply the IPCC AR5 with alarmist fodder prior to the March 15, 2013 publication acceptance deadline. Expect many more reports of the hazards of carbon dioxide in the coming months.

Trends in Northern Hemisphere Snow Cover

Having recently returned from three days of skiing in New Hampshire, I was interested to learn that according to the Rutgers University Global Snow Lab, last week marked the largest Northern Hemisphere snow extent since 1978 (a year that left an indelible mark on the memory of residents of the Boston area like me). On the day we returned home, my kids and I built an 11' Snowman Of Unusual Size (SOUS) from the wet snow that fell the night before we returned.

The excellent climate science blog of Anthony Watts, http://wattsupwiththat.com, recently had a guest post by Steven Goddard calling attention to the trends in Northern Hemisphere snow cover, as recorded by scientists at Rutgers University. I taught myself enough advanced Microsoft Excel skills to make these charts from the Rutgers data:

The first chart shows that since 1965 the Winter extent of northern snow cover varies widely around a fairly steady average of about 45 million square kilometers, while the Summer extent varies less, and has been decreasing by an average of 41 thousand square kilometers per year, which is about 1% per year.

The second chart shows how 2009-10 compares with the weekly average snow cover plus or minus 2 standard deviations, or a 95% confidence interval. Note that of the last 59 weeks of data, only the last point, week #7 of 2010, is "unusual" in the sense of falling outside the 2-sigma channel.

Mr. Goddard makes the excellent point that climate models used by the purveyors of the anthropogenic global warming (AGW) theory predicted that Winter snow extents would be decreasing for the past 20 years, rather than holding steady, and perhaps slightly increasing. I don't agree with Mr. Goddard that the recent apparent increases in Winter snow cover represent a significant trend, but there certainly is no suggestion of a decrease.

The Rutgers snow data supports the theory that the Northern Hemisphere is getting as much if not more snow than ever on average, but that it is dirtier due to anthropogenic soot which darkens the snow and is very potent at making it melt faster when exposed to the sun. If true, this would remove any need to invoke a warming climate explanation for the downward trend in Summer snow extent. However, the leading AGW proponent at NASA, James Hansen, with his coauthor advanced the claim in 2003 that sooty snow could itself contribute to AGW by decreasing the albedo of snow. It seems to me that the albedo of snow, given its high latitude, is far less important than the albedo of the tropical oceans, which is very sensitive to changes in cloud cover, and may be modulated by the interaction of the solar magnetosphere with cosmic rays.

Global Warming is NOT People!

Sometimes I feel like Charlton Heston at the end of Soylent Green, but instead of declaring "Soylent Green is People!", I'm saying "Global Warming is NOT People!"

For the past year or so I have been following the science and politics of Anthropogenic Global Warming (AGW), which is now supposed to be called "Climate Change," because those who seek political and economic power based on the control of carbon dioxide, in order to "Save the World", do not want to be impeded by the observation that the world has gotten cooler in recent years. In the process of following this science, I have accumulated and digested and enormous library of literature, some of which I hope to eventually post here.

A competing theory of why the Earth has, on average, warmed over the past century is based in variations in the Sun's activity. Solar-driven climate change has a great deal of evidence and theory behind it, and many well-qualified scientific proponents. I am convinced that it is the far better theory and have been sharing my conclusions with anyone who will listen.

Scientific arguments for the reality of AGW do exist, as exemplified by the IPCC's Fourth Assessment Report. However, most of what passes for argument against carbon dioxide emission in the public sphere is much more a religious or political stand than an assertion of science, especially when Albert Gore, and others, proclaim that the science is "settled," debate should stop, and bold action needs to be taken. This is to be expected, as Mr. Gore comes from the political world where debate is decided by voting, and the purpose of voting is to silence debate. Scientific debate is never decided by voting. It is decided by demonstrating that your theory succeeds where others fail. Even then the debate is not silenced. It is only a provisional truth, susceptible to revision or replacement by something better. Scientists, or anyone with a duty to the truth, do not defend their theories by condemning those who raise questions as counter-revolutionaries.

For many passionate anti-carbon dioxide activists, anthropogenic global warming is nothing less than the theology of original sin, with a church that regards the breath of human life itself as a taint on a fallen Eden, and a theocracy that would sell indulgences in the form of carbon credits, and tax all production.

The debate has taken on a new significance and urgency, because just as the governments of the world seem to be on the verge of capitulating to the global anti-carbon jihad, the world is cooling and the Sun is going through a lull in sunspot activity that is unprecedented in modern times. The current solar cycle's long slide to an ever-lower minimum resembles nothing more than the end of Solar Cycle 4, which led into the Dalton Minimum, a period of cooler temperatures punctuated by the disastrous "Year Without Summer" in 1816, following the eruption of Tambora. Several blogs have taken up the discussion of the controversy. I highly recommend ScienceBits by Israeli physicist, Nir J. Shaviv.

The popular science press has noted the recent drop in sunspot activity, and occasionally connected it to past solar minima and the associated cooling periods. Some have even raised the question of whether the decrease in the sun's activity will "offset" global warming, as if the overall increase in solar activity from 1850 to 2001 were a completely separate phenomenon.

The central controversy, in broad terms, is over how sensitive the climate is to small changes in heat flux. Increased greenhouse gases that trap solar heat contribute a positive heat flux. Increased clouds that reflect light contribute a negative heat flux. Variation in CO2 by itself, at relevant concentrations, traps far too little heat to account for the change that IPCC attributes to it. It requires a "multiplier" and water vapor is offered as the principal multiplier. Working Group 1 of the IPCC's Fourth Assessment Report adopts a model with high sensitivity, based on the fact that the most significant greenhouse gas is not CO2, but rather H2O, and that warmer air contains more moisture, providing a source of positive feedback. Variation in CO2 by itself, at relevant concentrations, traps far too little heat directly to account for the change that IPCC attributes to it.

One criticism of the IPCC's model it that it is unstable, being so sensitive to fluctuations in temperature that past CO2 fluctuations would have "run away" in a positive feedback loop many thousands of years ago, which is obviously not seen in the record. Another criticism is one that the IPCC itself calls the largest uncertainty in their model, which is the potential negative feedback effects of low clouds.

Since 1997, Henrik Svensmark has been arguing that most of the historical climate record, both ancient and recent, is explainable in terms of the modulating effects of the solar cycle on cosmic ray flux in the atmosphere. (See Svensmark H. Cosmoclimatology: a new theory emerges. Astronomy & Geophysics 48 (1): 1.18–1.24. A number of scientists, including Willie Soon of the Harvard-Smithsonian center for astrophysics, have produced research that confirms the solar cycle, particularly as it is recorded in proxies for cosmic ray flux, like Beryllium-10 and Carbon-14, is statistically a far better explanation for global temperature changes than is carbon dioxide.

As with carbon dioxide, the variation in the total solar irradiance by itself is far too small to directly explain the observed temperature changes. It too needs a "multiplier", which according to Svensmark comes in the form of the portion of the sun's output that deflects cosmic rays away from Earth. This varies by much more than the 0.1% of total solar irradiance. The part of the atmosphere that would be most sensitive to cloud formation due to increased cosmic ray ionization of the air is exactly the part to which the IPCC uses to amplify the small effects of man-made carbon dioxide, namely the moisture-laden air over warm tropical oceans. But for lack of nucleii for droplet formation, clouds would readily form. Ions produced by cosmic rays are said to form these nuclei.

Arnold Wolfendale of Durham University was recently quoted under the headline "Natural causes" not responsible for global warming, as stating that solar variation could not be responsible for more than 14% of the warming seen since 1956. As can bee seen in some of the attached figures, there is mischief in the choice of 1956 as the baseline, which was one year before the modern solar maximum's crescendo. 1956, 1957, 1958, and 1959 were the 12th, 1st, 2nd and 3rd most active solar years in the last 260 years of records. It is a little like saying that New Orleans is not sinking, because the average water level has not risen when compared to the peak of Hurricane Katrina.

The view of the man-made global warming skeptics, which appears sensible, is that the climate is less sensitive, and more stable than the IPCC models, and that this stability is manifest in the historical record, which includes periods that are both much warmer and much colder, and with much more CO2 than today. However, this relative stability can still be powerfully influenced by solar modulation of cosmic-ray seeded cloud formation.

The cruel joke that Nature appears to have played on climate scientists is that the Sun has been in a period of very high activity that rose from the Dalton minimum in the 1800s to a great crescendo in 1957, and has only recently started to subside. That this rising solar activity almost exactly parallels the Industrial Revolution and the increasing burning of fossil fuels has probably led many people astray in ascribing cause and effect. It is looking more and more like the sun is the driver, carbon dioxide is mostly just an effect of warming oceans (as warm soda goes flat), and anthropogenic global warming will join cold fusion and Lysenkoism on the ash heap of scientific history.

Now that we are in a period of very unusual solar quiet, the solar wind is at its lowest recorded level, and cosmic ray flux is at its highest. This not only has significance for climate, but also space exploration, as manned missions outside the Earth's protective magnetic field will be exposed to radiation from galactic cosmic rays at an all-time high, as will electronic components which can not be effectively shielded from these super-high energy particles.

I expect the coming decade will sort out who is right about climate, especially if the Sun persists in its current quiet ways. I hope our politicians don't cripple the global economy further in the name of reducing the output carbon dioxide, which is not a pollutant, and only weakly influential on climate. Although it is less than 0.05% of the atmosphere, carbon dioxide is a most precious resource. Every bit of carbon in our bodies was once CO2 in the atmosphere which nourished a plant, and then eventually us.