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Global warming is turning The Big Easy into The Big Sweaty.

Temperature data collected in NOLA by Harley Winer

Temperature data in NOLA evaluated by kong-term resident Harley Winer.

by Len Bahr, Ph.D.

On June 3 New Orleans resident and coastal hydrologist and engineer Harley Winer, Ph.D., circulated the above graph of warming temperatures in New Orleans to friends and colleagues. The graph is based on a regression analysis that Winer carried out, using three decades of data collected at the Louis Armstrong Airport during March of each year. Harley’s thoughts about the sobering implications of this temperature trend are presented here, slightly edited and condensed for clarity.

For those of you who doubt that climate change is happening I offer the following evidence that I abstracted from data available from the National Climatic Data Center ( First a little background is in order. 

When we first moved into our house in New Orleans in 1991 I ambitiously tried to control our electric bill by delaying turning on the A/C each year until the beginning of June, which became an increasingly uncomfortable and unrealistic exercise. This past spring during the latter part of March I was trying to avoid turning on the A/C one day and decided to investigate the local annual rate of temperature rise. The NCDC had a plot showing the average hourly temperature over the thirty years from 1980 to 2010. On this plot (not displayed here) the average daily high temperature first got into the 70s at the end of March, whereas in March 2017 the daily overnight low had climbed to just below the 70s.

I downloaded the data for thirty years, so as to determine the average March monthly temperature (i.e., the average of all hourly temperature readings) and to carry out a linear regression to determine the slope of the line. This regression (based on the data shown below) showed a slope of 0.148 degrees Fahrenheit per year, which is an extremely high number (14.8 degrees in 100 years if the same trend continued). The data show a lot of scatter depending on the frequency of cold fronts but the pattern is quite revealing. Another way to look at the data is to look at the average, minimum and maximum for the first ten years, the second ten years and the last ten years. The average for the past ten years was 64.22, compared to 61.52 for the first ten years for which I obtained monthly averages.

On June 12, Harley sent out the following additional comments:

In the e-mail I sent last week I listed the subject as “Climate Change,” when I should have used the term “Global Warming.” It is not climate change that is causing warmer temperatures; rather it is global warming that is driving climate change. This harks back to the Confucian concept of the rectification of names: “A parent should be a parent; a son should be a son; a king should be a king and a tyrant should not be called a king.”

The vested interests that want to ignore the “inconvenient truth” about the implications of increasing atmospheric CO2 concentrations, from an expanding population and increased industrialization powered by fossil fuels, have succeeded in framing the issue in the less threatening terminology of “climate change” rather than the more explicit phrase “global warming.” Words are important.

This reminds me of a situation that occurred when I was working for the Corps of Engineers. The vast majority of reports generated by the local Corps districts eventually go up to Congress, either for an authorization or for an appropriation. I was one of the first at the New Orleans District to report on relative sea level rise and how it would impact a project under discussion. If you go to the Bonnet Carre Spillway and look on the river side of the structure on the south end, you will see a very nice tile staff gage embedded in the structure. However, this staff gauge is now more than two feet off, because the land has subsided significantly over the last 86 years since construction. 

I don’t remember the specific project or the name of its manager but my evaluation, which included the controversial phrase ‘relative sea level rise,’ went up the line and when it came back I was advised to change “relative sea level rise” to “relative sea level change.” I was incredulous because the relative sea level change was obviously only in one direction. I asked who suggested this change and why, but all I could get out of the project manager was that it came from headquarters. I didn’t make the change but I would bet that he did before sending it back up the line.

What I surmise happened was related to the political climate at headquarters in Washington. Congress has the power of the purse and will frequently remind the generals at Corps headquarters of that fact, which induces self-censorship. Headquarters does not want to ruffle Congressional feathers with talk of sea level rise, even though relative sea level rise in southern Louisiana is 90% due to the land going down (subsiding).*

So to get back to global warming, most of the warming projections of 10 or 20 years ago have been exceeded. We are venturing into uncharted waters. We don’t fully understand the feedback loops. And frankly I am quite worried.

Three decades of March temperature data recorded at the New Orleans Louis Armstrong Airport

1988: 61.05, 1989: 62.28, 1990: 62.80, 1991: 64.16, 1992: 58.26, 1993: 58.73, 1994: 61.57, 1995: 62.90, 1996: 56.72, 1997: 66.79, 1998: 61.05, 1999: 61.95, 2000: 66.14, 2001: 59.74, 2002: 62.64, 2003: 62.34, 2004: 65.42, 2005: 61.06, 2006: 66.03, 2007: 65.46, 2008: 62.61, 2009: 65.30, 2010: 58.32, 2011: 66.72, 2012: 69.90, 2013: 59.47, 2014: 59.34, 2015: 65.47, 2016: 68.23, 2017 66.85

*Editor’s note: On June 14 | The Times-Picayune published a report by Mark Schleifstein on a new study carried out at Tulane University showing that coastal subsidence rates in coastal Louisiana are double previous estimates. Here’s a quote:

The new study measures only the sinking of ground and not the sea level rise of an additional 3 millimeters, or one 10th of an inch, says Torbjorn Tornqvist, a geology professor at Tulane and one of the authors of the study. The combination of subsidence and sea level rise is called “relative sea level,” which in this case would average 12 millimeters across the coast and 15 millimeters, approaching two thirds of an inch, in areas with the fastest subsidence.

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  1. Judging by the way you write, you seem like a professional writer…’;~

  2. Edward Bodker says:

    I find the following quote very interesting as a question regarding partisan politics and climate change. It seems to be asking the question of whether or not unlimited economic growth is bumping into ecological limits and if this will be a growing problem. The answer may be used as the fundamental reasoning to argue for or against Climate warming. If the projections of climate warming are close to the truth then it seems a steady-state economy is not only desirable but essential. But those who believe in unlimited growth economics will challenge the scientific method, if it is used to project a scenario that unlimited growth has limits.

    “The world’s mounting ecological problems have brought about a widening interest in the concept of a steady-state economy. Critics of the steady-state economy usually object to it by arguing that resource decoupling, technological development, and the unrestrained operation of market mechanisms are fully capable of overcoming any resource scarcity, any rampant pollution or any overpopulation ever to be encountered on Earth. Proponents of the steady-state economy, on the other hand, rebut that these objections remain insubstantial and mistaken — and that the case for a steady-state economy is gaining leverage every day.”(Wickapedia)

  3. Kelly Haggar says:

    A few quick points, in no particular order of importance . . . .

    1. Ran into a “luker” recently; someone who reads this blog but never posts. Enjoys the threads and requested I resume commenting here. OK; will do. Or will do at least one more time.

    2. Years ago, but after Katrina, Kathy was a guest speaker (on Goose Point near Lacombe) at the New Orleans chapter of a national geology-related society. At my table, there was interest in the Corps’ possible liability for levee failure. I never met the late Fred Chatry (d.1997) but I know people who knew him well and they speak highly of him. (Those of you who need a quick history of his tough call from 1985 should try: I played “What if?” at that table for a few minutes. Instead of the Regional Planning Commission being the only agency outside the Corps to be told of what became Zilkoski and Reese in Nov of 1986 [Subsidence in the Vicinity of New Orleans as Indicated by Analysis of Geodetic Leveling Data; NOAA Technical Report NOS 120 NGS 38, National Oceanic and Atmospherics Administration, Rockville, MD; 111 pgs], suppose Chatry and/or the Corps had gone the other way. Suppose he/they had gotten some private chats with the mayor, local big wigs, a few city council members . . . suppose he had been able to get those audiences . . . suppose he had been able to make his case . . . suppose they had decided to get on board, say with a bond issue for the 25% local match to raise the finished levees to the correct height and keep the new ones at those correct heights; suppose all that had come together . . . do any of you believe such a bond issue would have passed in Orleans Parish in, say, Nov of 1987? Nope. Not a person there thought it would have passed. My 2 cents was that the people of Orleans were denied the opportunity to choose. They could have sold at a loss, or moved to higher ground, or flood proofed, or bought more insurance, or even tried to talk their neighbors into voting “Yes.” Of course, as law worked itself out – – despite a few missteps along the way – – the overall correct legal answer was eventually found. The Corps was not liable for the failure of the levees, which I believe is the correct answer.

    3. But the policy choices behind budgeting and risk tolerance are more value judgments than they are either legal or engineering questions. Which brings me to a little essay by a (semi-) Green think tank troop who grew up to be a law prof. In 2007, Jonathan H. Adler wrote a book review (“Devaluing Science”) in The New Atlantis of The Honest Broker: Making Sense of Science in Policy and Politics, by Roger A. Pielke, Jr., Cambridge, 2007, 188 pp; available at: I believe just about everyone in the climate wars would be better off, as would the country, if we all looked for more Pielke type IVs and heard less from type IIIs.

    4. Finally, here’s the text of one of my slides when I speak to groups as varied as the local chapter of the Sierra Club and Gulf Coast Association of Geological Societies:

    SCIENCE is about “What’s a fact?”

    LAW is about “Which facts matter?”

    ECONOMICS is about “What do people want most?”

    POLITICS is about “What do most people want?”

    • Kelly Haggar says:

      Got a puzzlement on the four types of scientists. Pielke does not use Roman numerals; Adler’s original uses italics. Here’s the four types:

      [Pielke] lists four “idealized roles” scientists can adopt, each of which reflects assumptions about the nature of science and democratic policymaking.

      The first, the pure scientist [Kelly’s “type I”], is concerned with science for its own sake and seeks only to uncover scientific truths, regardless of their policy implications. Such a scientist has no direct connection with the policymaking process; he is content to remain cloistered in his lab while others hash out policy.

      The second idealized role for scientists in policymaking is less detached: the science arbiter [Kelly’s “type II”} is a bit more engaged with the practical world, providing answers to policymakers’ scientific questions. He wants to ensure that science is relevant to policymaking, but in a disinterested way. He does not wish to influence the direction of policy; it is enough to know that policymakers will make decisions informed by accurate scientific assessments.

      The third role in Pielke’s typology is the issue advocate [Kelly’s “type III”], who pays more direct attention to policy, using science as a tool to move it in the direction he prefers. He may work for an overt advocacy organization, such as a think tank, trade association, or environmental activist group, or his advocacy may be more covert. In either case, he seeks to marshal scientific evidence and arguments in support of a specific cause.

      Finally, the honest broker [Kelly’s “type IV”] is attentive to policy alternatives but seeks to inform policy, not direct it. “The defining characteristic of the honest broker of policy alternatives,” Pielke explains, “is an effort to expand (or at least clarify) the scope of choice for decision-making in a way that allows for the decision-maker to reduce choice based on his or her own preferences and values.” The honest broker’s aim is not to dictate policy outcomes but to ensure that policy choices are made with an understanding of the likely consequences and relevant tradeoffs. Like the issue advocate, the honest broker explicitly engages in the decision-making process, but unlike the issue advocate, the honest broker has no stake or stated interest in the outcome.

  4. Not Important says:

    This is the kind of article that makes the public annoyed with climate change. Most people realize and agree that climate is changing. But when a naïve article like this mixes “weather” and “climate” it makes people confused and lose faith in scientists. When you overstate your case, it makes you look desperate and makes you lose credibility. My 2 cents.

    • Not Important-
      You’re way off base, my friend.
      1) The public should be alarmed, not just annoyed with climate change.
      2) About 60% of Americans agree that climate is changing but fewer than 50% recognize its anthropogenic roots.
      3) This post represents an intriguing piece of data-based evidence consistent with the testable hypothesis that global warming is well underway, not just in the abstract Arctic but right here in our backyard.
      4) This post documents a consistent thirty year increase in temperature at one geographic site, which proves nothing but serves as a useful proxy for a frightening global phenomenon.
      5) The text never uses the term ‘weather,’ although it acknowledges signal noise from cold front passage, as noted by the author.
      6) The author and I both count ourselves as credible authorities on the topic under discussion, with opinions based on serious academic training, decades of real world experience in coastal engineering and coastal ecology, respectively. We also share deeply held concerns about the fate of our grandchildren, absent a global reduction in greenhouse gas emissions.
      You, on the other hand, don’t have the courage to identify yourself, let alone justify your intellectual standing to dismiss as naive a post that you don’t seem to comprehend.
      Len Bahr

      • Anonymous says:

        Is the true “scientific method” applicable to a system that defies verifiable conclusions?

        • Anonymous-
          1) I’m not sure what you mean by the TRUE scientific method, which implies the existence of a FALSE scientific method.
          2) Neither do I understand what you mean by the phrase ‘verifiable conclusions.’
          Our embarrassingly ignorant secretary of energy Rick Perry apparently believes that the overwhelming scientific consensus on the causal relationship, for example, between the documented Mauna Loa CO2 data since 1958 and the rise in global temperature over the same period is mere conjecture. Verifiable to Perry means absolute, eternal, irrefutable fact, a concept that doesn’t exist in science.

          • Edward Bodker says:

            Good distinction Len. From those who want to undermine science, the criticism is that science is not omniscient and that the interpretation of data is supposed to be perfect and verifiable. This criticism represents a warfare of ideology against science and in no way respects the scientific method. Those who engage in this type of partisan sabotage represent a desire to hold nothing to a higher standard. So sad to see how popular this has become. This is a true danger to society.

            • Anonymous says:

              I can see that this is going nowhere. What is your definition of the “Scientific Method”?

              • Anonymous-
                I’ll take that challenge. Here’s my definition of the scientific method, which involves observing an interesting natural phenomenon, the reasons for which are not intuitively obvious, and to propose and test a formal explanation (hypothesis) to clearly explain what is observed.
                This explanation involves repeatedly testing the hypothesis according to an explicit, statistically valid, experimental protocol that either confirms or disproves the hypothesis.
                The results of these experiments and conclusions drawn from them are then described in a clearly written draft submitted to a reputable technical journal, whose editor may reject the manuscript out of hand. Alternatively, she may circulate it for anonymous review by credible authorities in the field, who recommend either publication or denial.
                Acceptance and publication obviously doesn’t preclude the possibility that subsequent studies and new evidence require the abandonment of the original conclusions. In the meantime, humanity gains an increment of new understanding about our place in the Universe.

                • Anonymous says:

                  Sounds good to me. Using this method what is the temperature gradient for the next 20 years.

                  • I don’t understand your question about ‘the temperature gradient’ but I assume you’re asking what the mean March temperature at the NOLA airport is likely to be in two decades, based on Harley Winer’s regression analysis described above. In 20 years, according to the simplest hypothesis that the temperature rise is linear, the average temperature at that site in March, 2037 is likely to have risen 4.4 deg. Fahrenheit from about 65.0 to 69.4. During that time period, however, much change may have occurred and empirical knowledge will have been gained, including even the possibility that sea level rise has overwhelmed the levee system that currently keeps the airport dry.

                    • Anonymous says:

                      I give up. You win.

                    • Kelly Haggar says:

                      Anon- before you throw in the towel, check out:

                      Karegar, M. A., T. H. Dixon, and R. Malservisi (2015) A three-dimensional surface velocity field for the Mississippi Delta: Implications for coastal restoration and flood potential; Geology, June 2015; v. 43; no. 6; p. 1 – 4; Data Repository item 2015185; published online on 27 April 2015 as doi:10.1130/G36598.1.

                      [For their next paper showing a different sink rate pattern on the Middle Atlantic coast, see Karegar, M. A., T. H. Dixon, and S. E. Engelhart (2016), Subsidence along the Atlantic Coast of North America: Insights from GPS and late Holocene relative sea level data, Geophys. Res. Lett., 43, doi:10.1002/ 2016GL068015; available at: 1002/2016GL068015/full. ((Their 2017 paper is a book.))]

                      Meanwhile, there’s a good argument that rising seas are NOT the biggest threat to metro N.O. Lack of flex joints in the rigid T-walls is likely to be a larger threat. In Aug of 2015 I was 5 in a team of 5 presenting to the stars of the Miss Rvr Comm. The first 4 were geos and geophys types. I ran SEF/SES stuff from flight safety applied to civil works. They held me over for questions and the NO District (MVN) Col asked me some more after the talks had finished.

                • Edward Bodker says:

                  Len, as you can see anonymous wasn’t interested in a definition of the scientific method or about his pseudo question about temp. rise. By answering his challenge, he got you to do a lot of work trying to be reasonable and then he dismisses all you did with sarcasm. But your answers are well stated, perhaps others will appreciate them.

                  • Anonymous says:

                    The average temperature for the 30 year period is 58.9 degrees. The 1988 temp was 61.05, correct?

                    • Anonymous says:

                      Scientific Data collection and the interpretation of data rely on the total body of evidence collected. To isolate one point from a body of evidence is like walking outside on the coldest day of the year and saying the evidence does not support climate warming. Cherry picking isn’t part of the scientific method.

                    • Anonymous says:

                      Is this anonymous #1, #2 or #3? I think I am anonymous #4, just so my input is not confused by #1, #2, & #3.

                    • Anonymous says:

                      I counted 7 anonymous, not sure who is who.

                    • Anonymous says:

                      This anonymous situation is as foolish as predicting the future of the planet. It is in Gods hands.

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