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Perils and Pitfalls of Event Attribution

By: Dr. Ricky Rood , 6:37 PM GMT on March 11, 2011

Perils and Pitfalls of Event Attribution

Some of you may have noticed a story that originated in the Green Blog by John Rudolf on the New York Times website (March 9, 2011) about the Russian heat wave in the summer of 2010. The news story reports on a paper to appear in Geophysical Research Letters by Randy Dole and co-authors who conclude that in the historical record there is evidence of similar events of comparable intensity. It follows, they argue, that the Russian heat wave cannot be attributed to climate change – rather it is a very rare event. (Paper at GRL website, NOAA Description of Dole et al. article, Jeff Masters blog and analysis) For a variety of reasons I followed how this story propagated around the blogs and news services for the next 24 hours. It was picked up by many sites including, quickly, by the (according to comment writers on this blog) mysterious Steven Goddard (any more on that story?).

As it happens, I am writing an article for Earthzine with Christine Shearer on how scientists and the media engage each other about extreme events (Shearer blog on WU). When it is ready, I will proudly announce it and provide a link. That article will focus on a sociological analysis of extreme weather and the media. This blog will touch on a couple of the issues we raise in that article, but mostly it will be a scientist's point of view on the discussion of the value of pursuing the attribution of single events to climate change in a context largely described by public discourse.

Event Attribution: A public question that arises after every new extreme event is: can this event be attributed to climate change? At this point in time, I cannot imagine the answer to that question ever being, convincingly, yes. Scientists often rely on the statement: no single event can be attributed to climate change, but this event is not inconsistent with climate change. I have used that answer; perhaps, I repeat the mantra (Pakistan: A Climate Disaster Case Study). On thinking about that answer, it is more than useless. But then thinking about the question, it is, depending on your point of view: a natural question, a naïve question, an ill-posed question, or a leading question.

Why do I say that I cannot imagine the answer to such an event attribution question being convincingly yes?

Dole et al. study attribution, and they do it magnificently. Their strategy is to do a physical, statistical, and process analysis of historical information. If they find like events in the historical data, then that makes it impossible to attribute the event, wholly and solely, to climate change. This implies an odd metric: an event that is “caused” by climate change must be different than any event that has been previously measured. Do we have to have some Day After Tomorrow event where physical principles are suspended and the world moves to a whole new set of behavior?

The probability that looking through all of the observations, all of the history, that you are going to find a “like event” is high. I say “like event,” because there will be some differences no matter what. Of course, it has been hot in Moscow before, so there is some atmospheric pattern that yields “hot in Moscow.” We find like events and then, maybe, the current event is 10 degrees hotter and two weeks longer; it’s a obvious record. But is it climate change?

More likely than a obvious record, there will be another event that is similar, about the same, but not quite. Then it becomes the same question as, was Henry Aaron better than Babe Ruth? Aaron hit more home runs, but there are lots of other differences that experts point to and argue about: length of season, quality of pitching, … . Throw in Barry Bonds and Mark MacGwire; they hit a lot of home runs. Well maybe the physics (or physiology) of Bonds and MacGwire are different? Is climate change weather on steroids?

Suppose you look through the record and find that the current event is 10 degrees warmer and 2 weeks longer. Is it climate change? Do you know whether or not that if you had just one more year of observations, that you would not find out that that next year had a similar hot period. What about similar events in the medieval warm period? The data system was relatively sparse 100 years ago; maybe we just missed the event. So even if we find an event that is more intense, more persistent, then we have the problem - have we really observed the historical extremes? Have we observed all natural variability? This will always challenge the public and political discourse on event attribution - always.

More likely than finding an event that is extraordinarily different, we find an event that’s about the same length of time, but one degree warmer. Is the thermometer good enough? Are the instrument sites good - have they changed? What about the urban heat island? What about regional water management projects? Good scientific investigation and analysis can account for these issues, but in any event they are sources of differences, which as in the Aaron versus Ruth argument, are irreducible. Perhaps an extreme record can be established, but then, would that be climate change?

It is hard to see how playing the game of defining extreme events and then attributing that event to “climate change” can ever be won. It is often possible to isolate with statistical certainty descriptions that the emissions of greenhouse gases have influenced an event, but that represents one of those paths of nuanced explanation. Such nuanced explanation, again, assures there is not a definitive "yes" in the public and political discourse. In fact, it seems like it is a game that necessarily leads to controversy, and controversy is the fuel of talk radio, blogs propagating around the world, and the maintenance of doubt.

But what about that question of attribution? Let’s say you find an event that is rare, that is extreme, but not a new record - does that really say that the event today, right now, is not climate change?

In a very basic, old fashioned way, weather and climate are different descriptions of the same thing. They depend on how we, somewhat arbitrarily, define how we want to organize the observations. Crudely, we average weather to make climate. Since we work from the premise that climate change will be slow, for the most part the same type of weather events will make up the old (natural) climate and the new (changed) climate. Over time, the frequency of events will change, what were rare events in the old climate, might just be less rare events in the new climate. I pose, however, that even in a world that is on average four degrees warmer than today, there will be a seventy two degree, sunny day in the spring in Washington D.C. Do we then march through the days 50 years from now and say, “old climate,” “new climate?” The idea of isolating a single event on a single day or a persistent event and asking if it is caused by climate change – does that make sense? Is it even meaningful given the definition of climate? How did we arrive at the question of climate change being a causative of a weather event?

I want to restate the previous paragraph in a different way. Let’s assume that climate is averaged weather. Then climate is defined by a mean, a standard deviation, and a set of more sophisticated parameters that describe statistical distributions. What we have come to call the natural climate is defined by certain values of the mean and measures of deviations from the mean. The future, changed, warmer climate will have different values of the mean and the measures of deviations. With the presumption that the warming of the climate is incremental, then the majority of the events in the warmer climate will be like the events in the “natural” climate. Therefore, just because a like event existed in the "natural" climate does not mean that the current event is not part of the "changed" climate. There are NOT two climates - a natural one and a changed one - with our job being to determine if we have flipped from one to another. When we say that there will be more extreme events in the changed climate, it does not necessarily mean there will be a relentless unwavering string of records. There will, perhaps, be more events that have been previously rare. But, it is not climate change causing weather events.

As you study climate change, it becomes clear that talking about independent isolated events is not especially productive when trying to address attribution questions. Climate is an average, or perhaps better, an accumulation of weather events. As such it is important to consider how a large number of events act in concert, in correlation, in cohesion.

One other point that I want to make: The practice of isolating a single event and attributing that event to climate change, is one of the most effective ways of opening up scientific investigation to effective scientific criticism. (see Pielke, Sr. et al. 2007) A single-event attribution claim is an open and appropriate invitation to those with knowledge of or interest in local information to investigate the attribution claim. Almost inevitably this leads to identification of more sources of uncertainty, which like the Aaron versus Ruth argument, are irreducible. This necessarily contributes to controversy, and controversy is the fuel of talk radio, blogs propagating around the world, and the maintenance of doubt.

This entire process of event attribution is one place where scientific investigation of the climate interfaces with the media. Therefore, it is also a place where, by definition, scientific investigation interfaces with the political argument. My analysis above suggests that, as framed by the public discourse, the pursuit of the path of event attribution and the explicit or implicit linkage of that attribution to climate change is scientifically questionable. This stands in contrast to the scientific pursuit of extreme events in historical context and the evaluation of whether their frequency of occurrence is changing. Politically or in terms of informing the public, the primary product of the pursuit of event attribution is to build and maintain doubt. The exception to doubt maintenance would be if a definitive, metaphorical smoking gun was discovered. But what is the probability of such a smoking gun being discovered in this process? A different perspective is needed on the role of extreme events in climate and the attribution of such events to global warming. As climate scientists, we have to think about what these studies mean to the body of our field’s communication of climate change.


And here is

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Reader Comments

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Quoting weatherboy1992:
Cochise000 are you the same person as the Cochise111 that was banned? Before Cochise111 was banned, he was posting a lot of stuff that people never said, and personal attacks too. Would you agree that Cochise111's permaban was justified?
Almost everyone that posts in here was perma-banned at some point. Most recently, yourself.
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LOL...I'm beginning to think that just about everybody on here has or has had multiple handles.
Member Since: December 31, 1969 Posts: Comments:
Concerning №s 41-45:

Apparently this comes from testimony Dr.Hansen gave the Senate Environment Committee in 1986. Here is a link to a newspaper from Oxnard, CA that carries quotes from Dr.Hansen around the same time. I tried to find the Congressional Record for this but apparently only 1994 and later records are available online.

Concerning Steven Goddard: In the link he seems to simply be pointing out an article that appeared in a newspaper. It appears to be correctly sourced. Certainly he doesn't have to be scientist or climatologist to blog about Dr.Hansen's past predictions as long as he sources his information.

Bottom line...it could be a misquote, but newspapers have commonly been cited as sources here and on Dr.Master's board as reasonable sources. It certainly bears further investigation I guess; it would be nice to see another source.

* * *

№ 46

LOL...I was wondering how long it would take for Joe Romm to figure out a way to spin that one. Dr.Masters had a post on the NOAA study of the 2010 Russian heatwave a few days ago: Russian heat wave of 2010 due to natural causes: NOAA study.

Added: Actually, to be fair, it looks like Joe Romm had Dr.Trenberth do the spinning for him.
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There was also this study suggesting that, even if Russia's event has occurred within pre-industrial conditions, it will likely become more frequent in the future: Link
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Quoting McBill:

Maybe it's true and maybe it's not. We have no way of knowing for sure without seeing this alleged EPA analysis. Unfortunately, cochise is unwilling/unable to provide a link to the source.

Maybe you have evidence to back up your claim?

In the meantime here is some other reading for you:

Leading climate alarmists claim that global greenhouse gas emissions need to decrease to 60 percent below present levels by 2050 if humans are to avoid catastrophic climate change. But such a drastic emissions reduction is at odds with the world’s energy needs. Economists predict that an 80 percent increase in global energy demand will cause global greenhouse gas emissions to grow by 70 percent by mid-century.

CO2 Emissions by Region
Almost all the increase in energy demand and emissions will come from developing countries, where a quarter of the global population lacks any access to electricity. Indeed, almost half of the world’s people have to rely on traditional biomass, agricultural residues, and dung for cooking and heating. These countries will require tremendous amounts of energy if they are to grow their economies and escape poverty.
Given the reality of increasing energy demand in the developing world, the only way to reduce emissions is de-carbonize energy production. Yet fossil fuels account for 85 percent of the world’s primary energy for a very simple reason: They are the world’s least expensive source of energy. Therefore, a carbon-free energy future is an expensive energy future.
According to the U.S. Department of Energy, annual global greenhouse gas emissions need to be reduced by 30.3 gigatons a year by 2050 to reduce emissions by 50 percent by 2050. To get an idea of the costs of de-carbonizing energy production, consider the chart below, which depicts actions that would “save” 1 gigaton of CO2-equivalent per year:

Actions that Provide One Gigaton CO2 per Year of Mitigation or Offsets
Someone would have to pay for all those new nuclear power plants and wind turbines. The International Energy Agency estimates that halving global emissions by 2050 would cost $45 trillion. That is $45 trillion above the cost of fossil fuel energy that would not be spent to create wealth. That would take a big bite out of global prosperity. Much is said about the so-called “consensus” on climate science, but the economic consensus is that reducing emissions reduces economic growth.
Making energy more expensive would be catastrophic for the developing world, for which access to affordable energy is a precondition for economic growth, the most important driver of human well-being. Costly emissions reductions policies would rob the world’s poorest people of opportunities to escape poverty.
Alarmists claim that rising temperatures threaten human welfare—but reducing emissions from energy production also threatens human welfare, especially in the developing world, since doing so limits economic growth. So what is worse, the warming or the policy?
The question we have to ask is, “What’s Worse? Climate change or climate policy?”
In a Cato Institute study, Indur Goklany suggests that climate change is unlikely to be the world’s most important environmental problem during the 21st century, because a richer but warmer world is better for human welfare than a colder but poorer world would be.

The Cost of Global Warming
In his book Cool It, Danish statistician Bjørn Lomborg applies a cost/benefit analysis to climate change mitigation measures like the Kyoto Protocol, and finds that they are a tragic waste of money. According to his research, we could spend a fraction of the cost of climate policies on immediate problems, like HIV or malaria, and save millions more lives than global warming would take.
Dr. William Nordhaus of Yale University estimates that 3°C of global warming would cost the world $22 trillion this century. Al Gore’s package of measures, which calls on the U.S. to “join an international treaty within the next two years that cuts global warming pollution by 90 percent in developed countries and by more than half worldwide in time for the next generation to inherit a healthy Earth,” would reduce warming costs to $10 trillion, at a cost of $34 trillion.
Climate change might harm human welfare, but so would climate change policy. Policy makers should assess and weigh both sets of risks before deciding on a course of action.

Here is a 'link for the charts:
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Quoting Cochise000:

If I were writing a thesis, I might be more concerned with attribution. This is a freaking weather blog, which 25 people in the country have read at this point. Didn't you make the attribution comment once already? I would say that the majority of WU bloggers read WUWT. After all, alarmists must see what the enemy is writing. Of course they are going to see the origin of my post. As usual, attack the messenger, not the data. Do you think he's making it up?

There is a standard procedure here when you post something that an alarmist can't deal with. They attack you and they attack the credibility of the references.
The truth is your post is rather simple. The cost is enormous and the benefits are questionable even according to the EPA.
Now I just wrote a truthful statement.
Watch what happens. Either the post will be disregarded or I will be attacked. No one will make an attempt to disprove what I said because it can't be disproved because it is true.
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CycloneBuster, your idea could have aided in the Japan Disaster. With your idea there wouldn't be any need for any Nuclear Energy, therefore Zero Radiation leaking in the environment. I'm SOLD good looking out.
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Global Warming, R.I.P.
By Alan Caruba

Have you noticed that you rarely hear “global warming” mentioned on radio or television and the term rarely occurs any more in the print media?

One reason is that it has been replaced with “climate change” and the other reason is that the only people talking about climate change seem to be leaders of governments like the United States or Australia.

To borrow a line from Shakespeare, I come to bury global warming, not to praise it.

An early and unrelenting skeptic from the days it first debuted in the late 1980s, I rather instinctively knew that the only warming occurring was the same natural warming that always follows a cooling cycle; in this case the warming that began in 1850 after the Little Ice Age that began around 1300.

It never made sense to me that “industry” should be blamed for pumping massive amounts of carbon dioxide into the atmosphere when the amount of CO2 was a minuscule 0.038 percent with far greater amounts of hydrogen and oxygen that protect the Earth from becoming the galactic equivalent of a toasted marshmallow.

Then, too, like oxygen, all life on Planet Earth is dependent on CO2, a gas that the Environmental Protection Agency is actually calling a “pollutant.” That is so absurd that I was confident people would laugh the whole “theory” out the door when it was first proposed. But that was over two decades ago.

The end didn’t begin until November 2009 and the release of thousands of “Climategate” emails between the meteorologists supplying the bogus data that the United Nations Intergovernmental Panel on Climate Change (IPCC) used to generate the greatest hoax of the modern era.

Not since the discovery of the “Piltdown Man” had so many scientists allowed themselves to be taken in by a complete fabrication; one based entirely on falsified computer model data. Worse still, many climbed on board the global warming bandwagon to reap some of the billions in grant money involved.

The fact that “global warming” was generated by the United Nations should have been the red flag that something was not just wrong about it, but that it hid an agenda aimed at Western industrialized nations.

I think global warming gained credibility as much from the support of the leaders of Western nations as from the great difficulty skeptical scientists encountered in gaining any traction against it. To this day President Obama still prattles on about the need for solar and wind power to replace fossil fuels in order to avoid “climate change” from their use.

The current Prime Minister of Australia is busy trying to impose a carbon tax on that nation. The British have dug themselves a deep hole by embracing windmills instead of coal mines. Billions have been wasted by Spain and Germany on alternative energy sources.

The anti-energy agenda will have devastating affects on life in the West. Electricity consumers in the United Kingdom were recently told by the CEO of the country’s grid operation that, by 2020, they will have to get used to having no electricity for periods during the day and night. This will put the U.K. on par with North Korea. And the U.S. is not far behind if it does not quickly reverse current energy policies.

In the U.S., the leading voice for “global warming” became the former Vice President Al Gore who, following his defeat for the presidency, set about becoming a multimillionaire with all manner of “global warming” projects and enterprises. He would eventually win an Oscar for his documentary and a Nobel Peace Prize that was shared by the IPCC. Today, however, Al Gore is a joke.

The legacy of “global warming” has been the decades-long attack on U.S. energy sources until today our vast resources of coal and oil remain in the ground instead of being available as the price of oil increases due to troubles in the Middle East and the cost of electricity increases due to laws mandating that utilities must buy from wind and solar electricity producers who would be out of business by next week without those government mandates.

The public acceptance of the “global warming” hoax has waned even as the mainstream media has tried to hide the truth. The rise of the Internet has seen to that and other more pressing, real challenges are shoveling dirt onto its grave. 9/11 refocused public attention on a real threat. The 2008 financial crisis still holds the nation in its grip.

And a President whose first two years have generated massive resistance now only occasionally references “climate change.”

The global warming corpse is not quite dead, but dead enough for now. The question is what new fraud will the United Nations and environmental organizations perpetrate? The “acidification” of the world’s oceans? “Species extinction” or “Invasive species”? Be assured, the UN mafia is at work on something.
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Aliens 'already exist on earth', Bulgarian scientists claim
Aliens from outer space are already among us on earth, say Bulgarian government scientists who claim they are already in contact with extraterrestrial life.

Alien April Fool provoked fears of a genuine invasion Photo: GETTY IMAGES8:00AM GMT 26 Nov 2009
Work on deciphering a complex set of symbols sent to them is underway, scientists from the country's Space Research Institute said.

They claim aliens are currently answering 30 questions posed to them.

Lachezar Filipov, deputy director of the Space Research Institute of the Bulgarian Academy of Sciences, confirmed the research.

He said the centre's researchers were analysing 150 crop circles from around the world, which they believe answer the questions.

"Aliens are currently all around us, and are watching us all the time," Mr Filipov told Bulgarian media.

"They are not hostile towards us, rather, they want to help us but we have not grown enough in order to establish direct contact with them."

Mr Filipov said that even the seat of the Catholic church, the Vatican, had agreed that aliens existed.

He said humans were not going to be able to establish contact with the extraterrestrials through radio waves but through the power of thought.

"The human race was certainly going to have direct contact with the aliens in the next 10 to 15 years," he said.

"Extraterrestrials are critical of the people's amoral behavior referring to the humans' interference in nature's processes."

The publication of the BAS researchers report concerning communicating with aliens comes in the midst of a controversy over the role, feasibility, and reform of the Bulgarian Academy of Sciences.

Last week it lead to a heated debate between Bulgaria's Finance Minister, Simeon Djankov, and President Georgi Parvanov.
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Quoting MichaelSTL:

Michael, answer these very simple questions. Is the Earth's surface cooler or warmer than this time last year? Is the worlds's oceans average temperature cooler or warmer than this time last year?
So, what is it you are trying to say, to prove? That's what I thought. Just distraction.
I suggest you keep putting your eggs in the Arctic ice extent basket for now. It's really all you have going for you right now. Eventually it won't work for you, but maybe something else will. That's the nature of climate, isn't it?
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Quoting Cochise000:

Widely discredited? By whom? As per usual: just attack the messenger, but don't dispute the facts.

You ain't seen nothing yet. Cyclone is currently building his case for AGW causing the earthquake and tsunami.

In the alarmists world all bad things can easily be attributed to AGW and nothing good can be attributed to a warming world. Funny, isn't it. The Earth has been warming for at least 150 years and things have gone pretty well relative to the cold period that preceded it. Now an alarmist won't agree with that statement much as religious alarmists claim that modern society is destructive to man.

Alarmism is a religion and as we all know, no argument, no matter how logical, will impact the kind of intolerance that religious conviction brings.
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Dr. Ricky Rood's Climate Change Blog

About RickyRood

I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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