That Precautionary Principle

October 10, 2018

football

Long ago, when it was still acceptable to voice doubts about computer projections of the climate apocalypse, people often answered critics who mentioned the uncertainty in the predictions by citing “The Precautionary Principle.”  This self-evident axiom of risk management means that if the consequences of a low-risk, uncertain event are so catastrophically awful, we are prudent to act as though the event will happen.  So, even if the predictions about climate change are not very certain, the impacts on us if they turn out to be true are so horrific, we might as well not argue, and just assume that they are correct.  Case closed.

When I first began to track the issues related to climate change more than twenty-five years ago, that was pretty much my point of view, but after a lot of thought, discussion, and experiences at conferences, I have modified my view to one of rather harsh skepticism.  I’m not going to discuss that process here:  I just want to dispose of this supposedly common sense precautionary principle (PP).

First, a little story:  My sister has an old friend that she has known for many years who suffered significant brain damage a long time ago when he fell and struck his head.  He is severely impaired these days, as though he had been the victim of a stroke.  He was quite robust and healthy when it happened; he just slipped on the ice one winter and banged his skull.  A fluke accident with terrible consequences.  Could happen to anyone, right?

Now, this sad event the befell my sister’s friend was forseeable.  After all, everyone knows that you can slip and fall on the ice, and many of us have done it, although with consequences that ranged more towards embarrassment than disability…but it could happen to us, even if we are not old and frail.  It happened to my sister’s friend!  The chances are not zero.  If you do research on it, you might find that they are not even considered trivial, so this is my question.  Given that the consequences of this accident, with a probability notably above zero, are so life-shattering, why don’t we all walk around wearing football helmets in the winter when there is ice on the ground?  It would seem to be a perfect and unassailable application of the precautionary principle.

The reason that we don’t wear helmets is that we all make our own calculations, knowingly or not, and assume that the risk is so vanishingly small that we need not worry about such a “fluke” happening to us.  We are totally unpersuaded by the logic of the PP.  Some people are so foolish as to never wear seat belts despite the much stronger statistical evidence in their favor.  We might think those people are nuts, but still not don the helmet in icy weather.

In the end, we are left with nothing but data, and our judgment about how powerful a case it makes for taking action.  The PP is simply a way of trying to shut down consideration of the data and the possible courses of action by asserting that only one alternative is possible and logical, but in practice, nobody reasons that way when they actually have to make a choice.

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Hot Time, Summer in the City…

September 11, 2018

Capture

click here for larger image

I just cannot stop thinking about this graph that appeared with this article in the NYTimes recently.  The piece discussed how the number of hot summer days, those above 90 degrees F, are projected to increase in the future, and it allows readers to enter their town and date of birth to see how the weather has changed between then and now.

Hmmm….  Well, we all know that climate is always changing, and we all know that it is warmer now, in general, than it was 100 years ago, but beyond that what does this article and its interactive graphic tell us?

I imagine that a lot of readers misinterpret the data plot and believe that it represents the rise in temperature in NYC over the recorded period:  my experience is that most readers of these articles in the Times are not too concerned with details of data and data presentation.  In fact, it is more accurate to say that the chart shows the number of “above 90-degree F days” in NYC over the period.  That is, a count of days, not temperatures.   Except that it doesn’t show that…  On the left there is some text that says that it shows the “average number of days above 90-degrees F.”  What does that mean?

If we look at the data point for the year 2010, we find a value of about ten days.  Ten days above 90F in 2010?  You could easily check the record to see if that is accurate. But the text says that ten days is the “average number” in 2010.  In that year, there were either ten days above 90F or there were not ten days.  An average does not enter into the discussion.  That would be as if we said that June, on average, has thirty days.

The confusion is eliminated when we read the FAQ and Methodology document to which a link is provided at the end of the article:  How many people do that, do you think?  We learn that the data plot shows a twenty-year moving average of the above 90F days for each year.  For example, for the year 2000, the number of above 90F days for 1990,1991, 1992…2000…2008, 2009, 2010 are added up and and divided by twenty-one (there are twenty-one years’ values) and an average is obtained.  For 2001, the same process is used, but the summed years begin with 1991 and end with 2011.  Moving averages are often used to smooth out the data curve:  in this case, without doing it the plot would be very “spiky” with sudden changes in the number of above 90F days from year to year.  Smoothing the data gives a better idea of the trend, but it is good practice to make clear up front that you have done so, which the authors of the piece do not do.

On the other hand, what about the years 2008 through 2018?  For example, take the year 2015:  we get a twenty-year moving average by summing the data from 2005 to 2015, and adding that to the data for 2016 to 2026…  Oops!  There is NO DATA for the years after 2017!!  The kindly scientists at the Climate Impact Lab of Columbia University have used model data, simulated data, or shall we say, created data in place of actual historical data.  They do, obliquely, note this fact in their FAQ and Methodology text, but you’d never know it by looking at the graph.

Consider this:  their models show temperatures rising and above 90F days increasing, so the tendline after 2017 is rising.  But unlike the rest of the graph, that is NOT actual recorded data.  For all we know, the data record during that period is flat, or perhaps moving downward.

And speaking of flat data records, at least in NYC, the period from 1990 to 2017 (keeping in mind that the data for 2008 to 2017 is not actually the historical data) looks pretty much horizontal, i.e. constant, not increasing.  But sure enough, we can be completely confident that the upward trend that begins…next year, will come about.

Well, we cannot be completely sure because the Climate Lab also tells us – they are honest, if not forthcoming – that the results plotted here represent the data range that two-thirds of the models project.  I’m used to hearing the IPCC and other outfits talk about high or very high confidence in projections, i.e. a 90 or 95% confidence interval, but here we have a “just likely,” …mebbe… confidence interval of 66%.  Of course, this is simply a statistical sample of modeled results, described with the unspoken assumption that the models are correct, or nearly correct, or more correct than not correct… 🙂  If all the models share a few assumptions and parameters that later are disproved, then the fact that 66% predict this is hardly something to inspire confidence.  This, by the way, goes for all the climate projection models.

It would be nice if this graph for NYC were to be published every year in the NYTimes.  Then we could see each year how accurate the projections actually were.  Instead, this plot will be forgotten, and next year there will be a new batch, showing the rise in this or that frightful metric after the fateful year at hand.

Of course, it could happen exactly the way they are claiming it will.  We shall see…!


The End is Near, again…

May 11, 2012
 
Just had to parse this one…
 
Game Over for the Climate 
By JAMES HANSEN
New York Times, May 9, 2012

GLOBAL warming isn’t a prediction. It is happening.  That is why I was so troubled to read a recent interview with President Obama in Rolling Stone in which he said that Canada would exploit the oil in its vast tar sands reserves “regardless of what we do.”[Most scientists agree that the Earth has gotten warmer in the last 150 years, but there is disagreement over just how much, and why.  The IPCC says it is highly confident that ‘most’ of the observed warming is due to mankind’s use of fossil fuels.  If the observed warming is 1 or 1.5 degrees, F, that’s 0.5 or 0.75 degrees due to mankind, so what about that other half?  It’s not much, anyway.]

If Canada proceeds, and we do nothing, it will be game over for the climate.  [The game will go on, with us or without us…]

Canada’s tar sands, deposits of sand saturated with bitumen, contain twice the amount of carbon dioxide emitted by global oil use in our entire history. If we were to fully exploit this new oil source, and continue to burn our conventional oil, gas and coal supplies, concentrations of carbon dioxide in the atmosphere eventually would reach levels higher than in the Pliocene era, more than 2.5 million years ago, when sea level was at least 50 feet higher than it is now. That level of heat-trapping gases would assure that the disintegration of the ice sheets would accelerate out of control. Sea levels would rise and destroy coastal cities. Global temperatures would become intolerable. Twenty to 50 percent of the planet’s species would be driven to extinction. Civilization would be at risk. [Saying that the tar sands contain more CO2 than we have produced throughout history sounds shocking, but could be said about any of the major fuel reserves, coal, oil, natural gas, that are left.  It amounts to saying that if we burn up everything on earth for fuel, we will have discharged more CO2 than in all of human history.  Similarly, there are more people alive today than the sum of all who have lived before.  It’s a sound-bite.  Hansen goes on to assume that this will happen quickly, and that the effects will be just as he predicts, although such a thing has never happened before.  He assumes the Doomsday scenario of polar ice meltdown, and ignores the possibility that if his predictions appeared at all correct, that people would stop using fossil fuels.  Right now they have little reason to, if they listen to just him.]

That is the long-term outlook. But near-term, things will be bad enough. Over the next several decades, the Western United States and the semi-arid region from North Dakota to Texas will develop semi-permanent drought, with rain, when it does come, occurring in extreme events with heavy flooding. Economic losses would be incalculable. More and more of the Midwest would be a dust bowl. California’s Central Valley could no longer be irrigated. Food prices would rise to unprecedented levels.  [Hansen has been making predictions for decades.  The only one that is indubitable is that the concentration of CO2 in the atmosphere did rise.  Will he keep score on these?]

If this sounds apocalyptic, it is. This is why we need to reduce emissions dramatically. President Obama has the power not only to deny tar sands oil additional access to Gulf Coast refining, which Canada desires in part for export markets, but also to encourage economic incentives to leave tar sands and other dirty fuels in the ground. [Glad he recognizes that he is being apocalyptic.  If we ‘reduce emissions dramatically,’ just what will be accomplished?  How much is ‘dramatic?’  Has he asked the Indians, the Chinese, and the rest of the developing world?  Most reduction scenarios that are at all technically, politically, and demographically plausible will have minimal impact, if his models are correct. ]

The global warming signal is now louder than the noise of random weather, [according to him, who made the prediction…] as I predicted would happen by now in the journal Science in 1981. Extremely hot summers have increased noticeably. We can say with high confidence that the recent heat waves in Texas and Russia, and the one in Europe in 2003, which killed tens of thousands, were not natural events — they were caused by human-induced climate change. [Whoa!  That’s a claim.  I wonder who he includes in that we can say?  I would like to see the scientists who will sign onto that statement!]

We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life. But add too much, as we are doing now, and temperatures will inevitably rise too high.[They will rise, but how much they will rise is the million dollar question.  His predictions depend on feedback loops that are speculative.] This is not the result of natural variability, as some argue. The earth is currently in the part of its long-term orbit cycle where temperatures would normally be cooling. But they are rising — and it’s because we are forcing them higher with fossil fuel emissions.

The concentration of carbon dioxide in the atmosphere has risen from 280 parts per million to 393 p.p.m. over the last 150 years. The tar sands contain enough carbon — 240 gigatons — to add 120 p.p.m. Tar shale, a close cousin of tar sands found mainly in the United States, contains at least an additional 300 gigatons of carbon. If we turn to these dirtiest of fuels, instead of finding ways to phase out our addiction to fossil fuels, there is no hope of keeping carbon concentrations below 500 p.p.m. — a level that would, as earth’s history shows, leave our children a climate system that is out of their control. [Hmm…is the goal to have a climate system that we control?  Then adding CO2 is the way to go!  We cause it, we control it!  I agree, however, that reducing the use of ‘dirty’ fuels is a good idea for a lot of reasons.]

We need to start reducing emissions significantly, not create new ways to increase them. We should impose a gradually rising carbon fee, collected from fossil fuel companies, then distribute 100 percent of the collections to all Americans on a per-capita basis every month. The government would not get a penny. This market-based approach would stimulate innovation, jobs and economic growth, avoid enlarging government or having it pick winners or losers. Most Americans, except the heaviest energy users, would get more back than they paid in increased prices. Not only that, the reduction in oil use resulting from the carbon price would be nearly six times as great as the oil supply from the proposed pipeline from Canada, rendering the pipeline superfluous, according to economic models driven by a slowly rising carbon price.  [Here here!  By all means, let’s tax carbon and make the cost more closely approximate the real cost, including all the externalities.  I’d love to see it!  We could do all sorts of great things with the money, including fund research on major alternative energy technologies.  At the very least, the result would be a serious drive towards efficiency and conservation.]

But instead of placing a rising fee on carbon emissions to make fossil fuels pay their true costs, leveling the energy playing field, the world’s governments are forcing the public to subsidize fossil fuels with hundreds of billions of dollars per year. This encourages a frantic stampede to extract every fossil fuel through mountaintop removal, longwall mining, hydraulic fracturing, tar sands and tar shale extraction, and deep ocean and Arctic drilling. [Well, here I more or less agree.]

President Obama speaks of a “planet in peril,” but he does not provide the leadership needed to change the world’s course. Our leaders must speak candidly to the public — which yearns for open, honest discussion — explaining that our continued technological leadership and economic well-being demand a reasoned change of our energy course. History has shown that the American public can rise to the challenge, but leadership is essential.[Agree here too, but not with him!]

The science of the situation is clear — it’s time for the politics to follow.  [If it is so clear, then why is consensus presented in terms of statistics based on computer projections that are subject to great uncertainty?  The amount of science that is clear, e.g. that CO2 causes some warming, does not occupy the core of what the policy debate is about, which is basically an assessment of risk.]   This is a plan that can unify conservatives and liberals, environmentalists and business. [Dream on, prophet.]  Every major national science academy in the world has reported that global warming is real, caused mostly by humans, and requires urgent action. [This is flatly untrue and dishonest.  There have been many statements that global warming is real, that humans contribute to it, and that if current predictions are correct, the effects could be serious.  That’s a very different statement.]  The cost of acting goes far higher the longer we wait — we can’t wait any longer to avoid the worst and be judged immoral by coming generations.


Those climate models…

November 22, 2009

Finding out what's in the black box!

I often wonder why the global warming doom-gloom-soothsayers have so much traction in the world.  Like right wing conservatives, they like to claim that they are victimized by a hostile establishment press, but the NYTimes, a pillar of the establishment, is certainly with them.  Check out the 230 comments on Andy Revkins DotEarth blog regarding the recent email disclosures from the CRU.  The Editors’ Selections, with the purpose of

…highlighting the most interesting and thoughtful comments representing a range of views.

includes 4 posts, all firmly in the camp of “How dare they publish this!  This is just normal science. Face it, global warming is a fact!!” So much for a range of views…but no matter.

But why do intelligent and scientifically literate people, including some who are quite reasonable, e.g., Andy Revkin, feel so confident that the AGW hypothesis has been established beyond doubt?  Frequently – check out those Selections – references are made to mountains, avalanches, piles…etc. of data that prove the point.  I think something is missing here:  I think it is the global circulation models (GCM) run on super computers that clinch it.  But there is very little peeking into those models – they are essentially a black box for most people:  numbers go in, Apocalypse comes out!

Without the models, there would be no terrifying scenarios, disturbing graphs showing steeply rising temperatures over decades to come, no tipping point doomsday model runs.  There would be some hard data (CO2 rising), a mountain of ice core, satellite, and surface data from which some would infer a clear trend, correlation, and causal mechanism;  there would be an interesting hypothesis about positive feedback amplifying the otherwise manageable temperature rise that might be caused by CO2 increases and that might or might not happen; there would be the same endless scientific haggling and argument over the way the numbers are handled by statistical routines and whether this or that presentation of the data is appropriate and meaningful; there would be no consensus.  The advocates of AGW would be a determined and inventive bunch, but they would be hard pressed to demonstrate that the rest of the world should abandon the null-hypothesis, i.e., climate and CO2 have always fluctuated- what’s so different now? –  and adopt their hypothesis.  Computer models change all that.

The GCMs give the AGW crowd the cover to say that they can predict (not with certainty, of course…) the future trend of the climate.  It gives them the supposed justification for stating that they have uncovered the “forcing function” that precisely quantifies the impact of CO2 concentrations on the climate.  It provides them with a rationale for assserting that their understanding of feedback mechanisms is corrrect and that their predictions are reliable.  This role of computer models is not often examined, rarely questioned, certainly not in the popular press.

It’s worth taking a look at the writing of Daniel Botkin, a scientist who was present at the creation of computer modeling in ecology, and who has a lot to say on the role of models in scientific investigations.  His basic point is that models are valuable tools for understanding a natural system, for trying out ideas of how changes in one thing may affect another, but they are not very good for making predictions.  His essay, Science and Soothsaying, is a good starting point.

Another critical view of computer modeling is the Pilkeys’ book Useless Arithmetic.  Orin Pilkey (not to be confused with the climate scientists father and son, Pielke Sr. and Pielke Jr., also with a jaundiced view of modelers’ work) is most known for his controversy with the US Army Corps over its penchant for pouring millions of dollars into pouring sand on eroding beaches.  These wasteful projects are often supported by very impressive computer modeling.

In thinking about this topic, I keep returning to a book published almost twenty years ago, Ice Time.  In its chapter, The Machine’s Eye, the author makes the point that the study of climate had become, in large part, the study of climate models.   He traces the rise of supercomputing in the investigation of climate, and notes that it has become “big business.”   The author is relatively uncritical of the use of the models, but he focuses more on their use to understand the mechanics of the climate system rather than to predict the future.  The chapter is the only extended discussion in layman terms that I have ever seen of just what computer models of the climate do, and how they are put together.  For that, it remains a very useful discussion.

Late Note on Revkin’s Blog:
Here’s some interesting comments following the controversy-click the number for link to full text
:

From a physicist who values scientific culture:   265. Frederick  UK

November 22nd, 2009
2:48 pm

… I cannot say whether AGW is a valid theory…What I can say is that Mann & co. have so undermined the scientific process that their results lack credibility. This has been a dark period for science. It seems that politics and science do not mix.

We need to put this behind us and get serious scientists who are not afraid to have their methods and results questioned. At the end of the day, there is nothing more convincing than facts and proper results. We need transparency but what we have here is a travesty!

From a true believer distressed at Andy Revkin’s lack of faith:  269. Wayne Hamilton Springdale, UT

November 22nd, 2009
2:48 pm
Your Dot Earth blog has changed since I started reading and contributing several years ago … I thought it functioned very effectively in describing the threat of anthropogenic climate change.But in recent months… you’ve become increasingly even-handed in balancing the opinions of AGW skeptics and proponents… You now seem to give equal time and credence to the knowledgeable and to the ignorant.
I’m sorry to report that your latest article on the CRU hacking gave me the impression that you no longer believe in the consensus of international science and the importance of that fact. It makes me sad to say this, but I’m no longer interested in following your Dot Earth blog. Good bye.

Also this one, with a potent warning for Revkin that goes to the heart of “he said, she said” journalism (emphasis added)261 John M.   San Francisco

November 22nd, 2009
2:48 pm

Hi Andy,

Comparing your NYT article on the controversy to the raw data, I find you are slanting the story, minimizing it, acting more like a press agent than an independent, hard-driving reporter. For example, you write:

“Some skeptics asserted Friday that the correspondence revealed an effort to withhold scientific information.”

The emails themselves clearly reveal an effort to withhold information, but you are describing this only as an assertion by skeptics.

Your article makes no mention at all of the obvious, and possibly illegal, effort to evade requests made under UK Freedom of Information laws.

A far better analysis can be found here: http://www.powerlineblog.com…

Andy, you are risking your credibility here.

John M.