Waiting Until We Are Sure:

January 9th, 2008 <-- by Richard Rood -->

Waiting Until We Are Sure:

I also write a blog at Wunderground.com. Since November the number of comments on that blog has exploded. Thousands and thousands of words are being written. Some things in the comments are crude, there is some good argument, and complaints about what might be called the climate change machine. Most of the people who write comments at Wunderground.com are people with more than a casual interest in the weather and the environment. They put up maps and figures. It will be interesting to look back on these comments some years from now.

I tried to extract and summarize some of the concepts that were appearing in the comments to the blog. (Here they are.) This blog will address one of the ideas that keeps coming up – uncertainty. There were a number of comments about uncertainty and the fact that our knowledge about climate change is based on model predictions. Several times and in several ways people have said “shouldn’t we wait until we are sure?”

Uncertainty is a part of science. Science does not systematically reveal a list of facts. Science is a process which involves the development and testing of hypotheses. The process is, formally, also transparent so that others can independently test the hypothesis. The process of science, the scientific-method, is not perfect, and it is not independent of the skills and emotions of its practitioners. However, it is, in general, a robust process that is open to challenge and testing. The knowledge generated by the scientific method is subject to change. A good scientific study generates a statement about what is learned, perhaps the knowledge, and a statement about what is uncertain in the determination of that knowledge.

Facts are developed over time, and could be viewed as knowledge whose uncertainty is very low. Theories evolve out of hypotheses that reveal related information.

Models: Models are used in all aspects of scientific investigation. Models are used in architecture and in economics. In fact, models are used in every day life. We use a model when we estimate how long it will take us to drive from home to work. We have the pure model that is distance divided the speed that we travel. We have the version of the model that determines whether or not we take the street with many traffic signals or the longer freeway that does not have traffic signals. We have the version of the model that worries about the possibility of congestion or traffic accidents. We consider rush hour, holiday traffic, the need to stop and get a taco, and whether or not 70,000 people are going to see a re-united Led Zeppelin as the opening act for “An Inconvenient Truth.” We have the model that follows from experience; that is, what have we learned from many years of commuting to work. We have an idea of how long it will take to get to work and some sense of uncertainty. Often we can collect information from traffic reports that help us define and refine the uncertainty for any particular commute. Models are everywhere; imperfect models are everywhere; and we use them to make decisions. (This model of distance = time X speed is not unrelated to a weather or climate model, which calculates the motion of air parcels.)

Types of models:

Intuitive or heuristic models: There are intuitive or heuristic models that come from our experience and observations. These types of models help us, in the beginning, to develop hypotheses. After much study, heuristic models allow us to extract the most important processes that describe the behavior of a set of observations.

Statistical Models: Statistical models are a formalized statement of our experience. We observe the behavior, and we define the mean of the observations and how the observations vary from that mean. We search for relationships that organize and define the variability; often we look for periodicity. Statistical models are often used to describe the stock market, and as William Sharpe said “The key issue is that past performance is a thin reed for how to predict future performance. …”

Physical Models: Another type of model is the physical model, which is based on physics that describe the behavior of the observations. For example, how far an air parcel moves depends on how fast the air parcel is moving and the forces that influence that motion. The strength of the physical model is that we have cause and effect, and with cause and effect we increase our confidence in the predictions that come from models.

All of these models are related; all have their use. For a physical system, like the climate, we often describe the behavior statistically and then work to extract the physical relationship that describes the behavior described by the statistics. The climate of the Earth is a complex system with many interacting physical processes of varying importance. The climate system is made up of many sub-systems. Some of these systems and processes we understand well; some we do not.

Decisions: We always make decisions in the presence of uncertainty. In fact a weakness often pointed out in sociology and management texts is the fallacy of waiting for uncertainty to be eliminated. It is skill or art to know when the uncertainty is at some sweet spot for decision making. It is my opinion that one of the weaknesses of U.S. climate science activities was the idea prevalent in the 1990’s that our investments in science would reduce the uncertainty for “decision makers.”

In decisions that are based on scientific investigation one must realize there will always be uncertainty. Good science includes an estimate of uncertainty. Uncertainty will be reduced for some aspects of investigation. In complex systems new sources of uncertainty will be revealed. This uncertainty can always be used to keep decisions from being made. Uncertainty can always be used to keep policy from converging. It is a form of argument, of rhetoric, of belief. ( Uncertainty and Climate Policy Blog at climatepolicy.org )

If we look at the climate problem then with high certainty we can say that the Earth’s surface will warm. Similarly, we can say that ice will melt and sea level will rise. It is far less certain what we can say about the specifics of regional drought and floods, but we can say with some confidence that the statistical behavior will change. People can and will make decisions in the face of uncertainty.

In the climate problem the non-scientific sources of uncertainty are, now, of much greater concern than scientific uncertainty. One of the reasons than businesses are so interested in the development of policy, is that the uncertainty of what the policy will be impacts the ability to make business decisions. As I pointed out in my report from the meeting on Chicago area businesses, these businesses see that we are past the point of arguing about the basic science; they need to know the policy environment in which they will be operating. ( Corporate Climate Response (Chicago) )

Conclusion: The argument that we must wait until we are sure is not the way we work as individuals or as groups or as a society. We always operate in the presence of uncertainty, and we choose which uncertainties we give priority. In the climate problem it is a point of argument, of rhetoric, or belief. Some will decide that the uncertainty is defined well enough to support their decision making; others will decide that the uncertainty is too large to support decision making. As with virtually every other aspect of life, these will form two groups, which can be described by the number of people in the groups, and if one group is much larger than the other then some will be motivated to say that there is a consensus. (Consensus (American Heritage Dictionary) 1. An opinion or position reached by a group as a whole. 2. General agreement or accord.)

Often if we wait until we are sure, then it is too late.


Wunderground.com prototype climate page.

8 Responses to “Waiting Until We Are Sure:”

  1. maril hazlett Says:

    “Uncertainty is a part of science.”

    it was very nice to read this.

    uncertainty is also part of life – sometimes I wonder if part of the psychology behind the “there must be certainty” argument comes from the need to have the world be a stable, predictable place where we can control what goes on. You have to be brave to face an unpredictable world where there’s a lot of unknowns, you might really screw up or have to backtrack quite a lot – and risk management skills come in very handy.

  2. anonymous Says:

    it is not only in the face of uncertainty that corporations are starting to take steps now – with the rest of the world taking action and U.S.-based multi-national corporations beginning to feel the heat of foreign standards and taxes, companies are pressuring Congress to take action now (see USCAP, for example)

  3. Tony Welsh Says:

    Could not agree more. It is interesting that we have adopted the precautionary principle by dropping interest rates 1.25% in a few days, but won’t do it for climate change. I have blogged this myself on tonysclimateblog.blogspot.com.

    It is as if we were headed for a concrete wall in a car and decided not to brake because we were not sure exactly how far the wall is, how badly the car would be damaged, or how exactly we might be injured.

  4. Anon Says:

    Un certainty is a part of science.

    Then why is science so certain that they know exactly what CO2 will and will not do?

    Why are we told that science has a consensus?

    How can you have consensus in uncertainty?

    I’ll tell you how, because everyone is guessing.

  5. Richard Rood Says:

    Consensus is a statement of general agreement and accord. It follows from the word consent. Consent and consensus are in the realm of judgment and do not imply an absence of uncertainty. I don’t think that the common usage of the word consensus implies that there is an elimination of contrary opinion. Further as the number of people involved in a problem and the complexity of a problem increases, the notion of consensus becomes one of majority, super majority, and over whelming majority. In the projection that increasing carbon dioxide will warm the Earth, I think it safe to say that an overwhelming majority of scientists would consent to support that statement.

    Consensus is, ultimately, in the realm of people. If you are trying to build consensus then you find a core set of ideas that people can agree to. This usually requires anchoring on notions and fundamentals, and the placement of detail outside of the consensus. The formation of a consensus allows the group to move on. Those details are left to be resolved over the course of time. The resolution comes from research, negotiation, or a variety of other factors depending on the problem at hand.

    Being in the realm of the judgment of people, consensus is fluid and dependent on all of the external and internal factors that influence people. It does not have the attribute of permanence or absolute. We do not have consensus, then move on and leave that consensus behind use as a stout stake in the landscape. In fact, consensus, is something that is built and rebuilt, it is in the toolbox of politicians, managers, and rhetoric. Consensus leads to mediocrity if it is used without a sense of evolution.

    Consensus that CO2 in the atmosphere will warm the surface of the Earth is accurately reported. Why is this conclusion reached — astoundingly simple and well documented physics. A guess? If it is a guess it is extremely well informed with correlated observations and the determination of cause and effect based on physical principles.

    Factually, we always act in the face of uncertainty. It is our choice how we use the uncertainty in our actions.


  6. Carl Milsted Says:

    Level of certainty required is a function of cost of action. A horribly complex, expensive and bureaucratic set of solutions requires more justification than a lower cost set of solutions.

    The simplest, most market based approach is a carbon tax. This is still expensive — until one realizes that other taxes are also expensive. I have laid out a conservative case for a carbon tax which points out the many benefits of a carbon tax as a replacement for one of the existing, more complicated taxes. I also did a first order estimate of the carbon tax level needed to replace the income tax which can also be used for estimating the possibility of using a carbon tax to replace a smaller tax.

  7. David B. Benson Says:

    Carl Milsted — I like to consider myself a Progressive in most matters political. So I’m pleased to read that at least one Conservative favors a fossil carbon tax.

    My take is that most economists consider a fossil carbon tax as appropriate and better than alternatives.

  8. Pete Says:

    If you wrote this in the early 1990’s, I’d be in agreement. The impacts of CO2 driven warming being predicted at the time definitely outweighed any minor uncertainties. I was 100% in favor of actions to reduce CO2 emissions and, besides, it aligned with trying to reduce NOx/SOx /HG and particulate pollution and also reduced use of foreign oil for National and economic security benefits.

    At this time, based on the technical info I’ve read, I have changed my position. I believe the uncertainty has become so great that it is no longer prudent to take radical action like carbon taxes and CO2 sequestration for the reason of reducing CO2. I’m actually amazed how much was already out there in the early 1990’s, but the internet wasn’t around yet for me.

    It appears to me that it is not unreasonable that research should focus on what appears to be the benefit of actually increasing clean CO2 emissions (take the pollutants out first) so plant growth would increase. Also, if we are actually entering a new cooling period (or ice age) as some suggest, increasing CO2 might help stave off a fraction of a degree of the cooling. Obviously, increasing CO2 by burning just for the sake of increasing CO2 is hard to imagine as being sensical, but that doesn’t mean there might not some other means of emitting CO2 that researchers might come up with.

    Also Governments should be funding some research on means of reducing high altitude clouds/ice crystals so that we can absorb more radiation and offset some of the inevitable cooling. If we keep developing the models maybe they’ll accurately represent the climate in another 10 years and they’ll be useful for policy decisions.

    If we want to do carbon taxes for other reasons, like as an alternate tax collection method to support alternate energy, energy efficiency, and environmental improvement, that’s fine, but for the sake of truth and integrity we shouldn’t let the politicals run with what appear to be closer to being untruths than certainties.

    Personal note: I have a strong math and engineering background, did some turbulence energy CFD modeling in 1980-1981, have long been frustrated that we don’t take better care of our environment, but also have a strong belief that science should not be hijacked by untruths. I’ve been out of it for awhile, but my technical background has allowed me to understand the various papers. Lastly, I will admit that I actually get very frustrated that truth and scientific integrity appears to have lost and may damage future scenarios where scientific input is needed to influence a real need. (I know, many things are not directly correlated and it may be that all the attention will actually help educate and improve societies technical fluency)

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