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.
By: RickyRood, 5:56 PM GMT on July 30, 2012
Models are Everywhere: Models, Water, and Temperature (3)
This is a series of blogs on models, water, and temperature (see Intro). I am starting with models. In this series, I am trying to develop a way to build a foundation for nonscientists to feel comfortable about models and their use in scientific investigation. I expect to get some feedback on how to do this better from the comments. In order to keep a solid climate theme, I am going to have two sections to the entries. One section will be on models, and the other will be on a research result, new or old, that I think is of particular interest.
Doing Science with Models 1.0: I have written a number of entries over the years introducing the role of models in climate science (Uncertainty (Model Types), Predictable Arguments). You will also find in those entries links to a couple of chapters in books, where I have written introductions to atmospheric modeling for scientists. (most recently, standalone chapter). There are several websites that offer an introduction to climate modeling, for example, We Adapt, climateprediction.net, NASA Earth Observatory, and Koshland Science Museum. A discussion I particularly like is Spencer Weart’s Simple Models of Climate Change. My friends who are expert in education tell me, however, that models, modeling, and the use of models are among the most difficult concepts to both grasp and teach. Often people do not feel comfortable with models as a representation of real things or, in the case of climate, with the real world. The consequences of this discomfort for climate change are far reaching, ranging from challenging how to use the information from models to providing an easy way to grow the political arguments of selective doubt.
Looking at the online resources that introduce climate models, many of them start with words such as “theory,” “numerical,” “computer,” and “mathematical.” They talk about representing the “physics” of the atmosphere, ocean, land, and ice as “coupled systems.” There are different ways that “complexity” is discussed. I often state that climate models are a way to “manage the complexity” of the Earth’s climate or that they are a “comprehensive expression of our accumulated knowledge.” Others talk about complexity in way that comes across as the climate and climate models are complex, and hence, it takes scientists to understand models. I can even find online resources that say that the climate is so complex that it is unreasonable to imagine that humans can build credible climate models. This cloak of complexity is one I will try remove in the series.
When I think about models, the first thing that comes to mind is the half hull of ships that ship builders used to inform the design and building of their ships. Following that thought, there are the models of buildings and shopping centers that are tools of architects and urban planners. These models not only allow seeing how a new building might fit into the environment, but they also serve as a way to, for instance, identify traffic congestion because of placement of parking lots and to communicate the design in the designer’s mind to clients and the public. Another practical example of this form of model is the mockup of, say, the electrical and plumbing systems in a big building to see how things fit together. Similarly, when NASA builds a satellite, there are engineering mockups that are used in design and planning that serve as basic tools to guide thinking about the construction of a complex system and to communicate to others in the project.
Figure 1: Half hulls of boats, a type of model. From Halfhull.com.
This type of model fits into the definition of a work or structure used in testing or perfecting a final product. As described, these are often touchable, real constructions that look like little versions of the real thing. Professionals in the field might call them “toy models,” which is not in any way meant to convey that they are less than serious. Increasingly, these models are represented digitally, using computers, to provide three-dimensional video worlds that you can walk through (Rick Kaplan’s 1963 Mickey Mantle Homerun). All of the details mentioned in this paragraph will, ultimately, be related to climate models; however, the initial point I want to make is that models are everywhere in our world. Rather than models being abstract ideas that are alien, models are, in fact, quite intuitive. They are one of the devices that we use to help think about our complex world. And perhaps more simply, they help in the quick construction of a picnic bench that can sit firmly on the ground and hold up three 200-hundred-pound men.
Interesting Research: Changes in the Arctic: Steering of Storms - Often when we talk of the Earth warming, we talk about the average temperature of the surface of the Earth increasing. It has already been observed, and climate models predict that the Arctic will warm far more and far faster than this average temperature. This is often called “Arctic Amplification.” There are many consequences of the enhanced warming of the Arctic, such as vast changes in northern forests, thawing of the permafrost, and, potentially, the release of large amounts of storages of the greenhouse gases methane and carbon dioxide. (WWF’s Arctic Feedbacks Review)
The specifics of the Earth’s climate are strongly related to the tilt of the Earth on its axis of rotation, the rate of rotation, the distribution of land and water, and the mountains on the land. It is because of these defining attributes of the Earth that we get different regional climate characteristics such as tropical and polar climate zones. In the United States, we mostly live in what atmospheric scientists call the middle latitudes. In the middle latitudes, storms are always working to even out the temperature differences between the tropics and the poles. As the climate warms, it is intuitive that the area of the tropics is likely to get larger, that is, tropical climates will extend closer to the poles. As mentioned above, there are already huge changes in the Arctic.
As the Arctic and tropics change, the jet streams change, and the characteristics of the storms that transport heat from the tropics to the polar region change. There is a very nice recent paper in Geophysical Research Letters by Francis and Vavrus, Evidence linking Arctic amplification to extreme weather in mid-latitudes. If there is a simple takeaway message from this paper, it is that weather features such as storms are moving more slowly and often of greater amplitude. Amplitude? Middle latitude storms are waves and well modeled as waves, and the amplitude of the waves are increasing. The impact of these changes is that weather events are more persistent, leading to more extremes of weather: floods, droughts, heat waves, and cold spells. All of these impacts occur when the weather gets stuck in a particular pattern.
What I specifically like about this paper is how they bring the observations back to fundamental theories and models of atmospheric motion (Holton: Dynamical Meteorology). Dynamical meteorology is a mature field of science with its principles checked in weather forecasting, observational field studies, and numerical modeling. When observations and models and theory are combined in a way that paints a consistent picture, we develop a form of scientific investigation that identifies processes, isolates cause and effect, and help us understand the ingredients of the complexity of the Earth’s climate.
Updated: 5:11 AM GMT on August 06, 2012
By: RickyRood, 4:46 PM GMT on July 15, 2012
Introduction - Models are not All Wet: Models, Water and Temperature (2)
I am starting a series of blogs on models, water, and temperature.
A couple of entries ago, I wrote a somewhat muddled blog, Difference Between Night and Day. My major goal in that blog was to look at how water, especially water vapor, enters into the climate and climate change problem. I used some regional differences in climate, say Florida's and Arizona's, with the hope of suggesting that we have some intuition of how water vapor modifies regional climate. For example, due to the absence of water vapor, Arizona's extremes of daily temperature are larger than in a much wetter Florida.
This simple intuitive notion, however, quickly falls into complexity. It is the typical complexity of climate science, where the members of a set of simple physical processes combine in many different ways to produce a difficult-to-untangle knot of observations. I will come back to this later, but first, here are some of the other ideas I had in mind in that first blog.
At the end of that blog I referred to the paper by Kukla and Karl, 1993, Nighttime Warming and the Greenhouse Effect (from Rood’s Class Website). This paper investigates the observed decrease in the range between nighttime lows and daytime highs. At the writing of that paper in 1993, the models of 20 years ago did not simulate this observation especially well. How does one respond to fact that models don’t represent a particular observation? A common way to respond, sometimes put forward by commenters on this blog, is that the models fail to represent the observations; hence, the model is wrong, and to base any conclusions, actions or behavior on model results is grievous failure of reason.
I, of course, reject this conclusion. When I get the result that the model does not represent an observation especially well, then I take this as a piece of information that motivates further investigation. The scientific investigations of my career have been based on the process that we develop a model from a set of physical laws that are expressed as mathematical expressions. The physical laws and the construction of the original model are based in their most fundamental way on observations. If the model has been developed properly, then it offers an approximation of that observed behavior. If this is the case, then we have an experimental tool that can be used for further investigation. That investigation is motivated both by the shortcomings in the model’s ability to represent observations we already have and by new observations that come along. In this approach models evolve as a tool that help us explore and manage the complexity of the climate system. They also help guide our thinking about the future based on the projections that come from the models. Models are, therefore, devices to help us think; they do not provide the answer.
Another idea that I introduced in the Difference Between Night and Day was that large changes in the amount of water at the surface, for example, the Dust Bowl and irrigation in the Corn Belt, might have significant regional impacts on climate. The place I am going with this, ultimately, is the Midwest Warming Hole (2 MB if you click), and that requires thinking about water. The Midwest Warming Hole is an observed feature in the center of the United States that is not warming up as fast as the regions around it or as fast as the models predict. This is not a newly discovered feature, but it is a feature that I think takes on new interest as we think about this hot summer, the last hot summer, and how to use the observations today to think about the climate in the future and how to adapt to a warming climate. The Midwest Warming Hole, and the ability or inability to represent it in models, is also a great example to help people think about how to describe model uncertainty.
The last big theme that I want to follow from the original blog is the improvement of ways to discuss and understand the role of water – solid, liquid and vapor – in climate and climate change. I did a series Just Temperature ( one, two, three) which was motivated by the stunningly warm spring in 2012 in the continental United States and my thinking of extreme events as climate change case studies. The Just Temperature series used the fact that the warming of the Earth has become large enough that it is possible using temperature observations alone to make a compelling case the Earth is warming. But once we make it beyond that fact, we have to think about water to understand the complexity of both the spatial and temporal structure of the observed trends.
So here are three big themes that I want to organize around:
1) Doing science with models
2) Communicating the role of water in climate and climate change
3) Thinking about changes in land use and its impacts on water
These will be interspersed, of course, with some tangents to interesting subjects here and there. But those who know this blog know that eventually I get there.
Updated: 12:44 AM GMT on July 17, 2012
By: RickyRood, 10:47 PM GMT on July 02, 2012
Belief and Knowledge and Humans and Nature:
I am starting this entry from a previous blog, Rhetoric Again - Cycles. I got some interesting comments as well as a couple of letters for that entry. To set the tone, here is a thought from the end of that blog.
There is little doubt that humans are the dominant life form on the planet today. We shape every ecosystem. We consume all forms of energy. Like the balances between plants and animals in the past we change the atmosphere and the ocean. Not only are we a dominant life form, we have this amazing ability to extract rocks and liquids and gas from the Earth and burn them. We have the ability to push around land, to make concrete, to remove mountains, and build islands. We are, therefore, not only biological, we are geological.
With this notion, I place humans as a force of nature – as part of nature. Because we have the ability to remember, reason, develop and accumulate knowledge, then unlike other parts of the natural world, we have the ability to make decisions that influence our future. Therefore, our role in nature, in the natural world is unique. To be clear, that uniqueness is not in our ability to change the environment, but in our ability to understand the consequences of those changes and the ability to anticipate and influence the future.
I bring up this idea of humans as a reasoned biological and geological force for several reasons. First, I believe that to set the world into two divisions, that which is natural and that which is human, is both a false and dangerous division. Focusing on climate change, it is a division that sits at the foundation of those who argue that the climate is full of natural cycles, and that the current warming is just part of that natural cycle, and hence there is no need for us to be concerned. Or alternatively, there is no need for us to modify our behavior because it is all a force of nature, and we don’t have any influence over nature. (see also).
This is a belief – mine, that humans are part of nature. But many others see humans as outside of nature. The outside perspectives are not simple. For example, there are those who see humans as a disturbance to nature, and there are those for whom humans have divine providence over nature. That is the second point I want to make, the very foundation of how we think about climate change, our environment, and our place in nature is belief based. It is a belief base associated with our personal identity.
I have been motivated to think about what we believe and how this impacts our behavior on climate change for many years. For the sake of this blog, that motivation rises from how do we communicate climate change? Some scientists spend a lot of time thinking about how to communicate their work; in fact, research sponsors often require plans for communication, outreach and broader impacts. Many scientists, trained in a discipline of evidence-based knowledge generation, fall naturally to presenting evidence-based arguments, with the idea that ultimately the evidence-based argument will be convincing beyond reasonable doubt. In many ways this invites an argument more suitable to our approach to legal problems. We the scientist will present the evidence base. This will stand in contrast to the arguments of the non-scientist. There will, ultimately, be judgment in favor of the evidence base, because, well, it becomes self evident. This form of argument does not recognize that we often look at evidence and make decisions that deny the existence of that evidence. We make decisions that align with, our desires, our beliefs and what we want to believe.
I have written about some of these communications issues, and they are compiled here in What to Do? What to Do?. What I want to state more explicitly than I have stated before is the importance of the recognition of the belief-based argument. First, I naturally contrast the belief-based argument with the knowledge-based argument, which is not really the right contrast. The belief-based argument is, in fact, informed by knowledge, but it does not give high weight to science-based knowledge. Hence, it is not especially useful to pose a belief-based versus a knowledge-based argument. I have already stated that both sides of the argument are belief based and that both sides on the argument are informed by knowledge. Hence, it is easy for these arguments to fall into an attack on identity – I the scientist work from the foundation of knowledge and the ability to generate knowledge. You do not. This is not useful.
Second, I have used belief-based argument with the idea that it might be viewed as a politically based argument or even a religion-based argument. I have often referred to the politically based argument in my blog entries, and I have stated that once in a political argument, where the foundation is not primarily science-based knowledge, there is really little purpose in arguing over facts and evidence-based knowledge of the Earth’s climate. There is even evidence that introduction of science facts increases the polarity of political arguments (here). In such an argument, people may be working from a different base of facts. This is especially evident in the arguments over biological evolution, divine creation and, say, the observation-based scientific description of progression of Earth’s life and climate.
Where am I planning to take this blog? The first place I want to take it is that the communication of climate change is complex and individual. If we mash together evangelical, conservative, and Republican as dismissive of climate change and view a concern for climate change as secular, liberal and Democratic, then we do disservice to all. It does not take much effort to reveal evangelical, conservative, Republican organizations that are concerned about and vested in ways to address climate change. That is why in the 2012 political environment, a focus on exposing those seeking solutions is a more useful way forward than perpetuating the political arguments and despair over the political response. There is no simple key that will be uncovered by a compelling presentation of knowledge; there is no single approach to communication that will be universally effective. Successful communication is purpose-based and recognizes the valid points of view brought to the table by all constituencies. It often requires overcoming barriers of prejudice.
The next place I want to take this blog is to return to the idea of natural cycles – climate variability. We have been faced with many environmental challenges. I am sitting in St. Cloud, Minnesota, in a region that was largely deforested many years ago, on the Mississippi River, which has too much nitrogen-based nutrients in the water. A few miles back I saw a bald eagle, a species that was endangered by DDT. We eliminated the use of DDT, and we have seen the return of the bald eagle and the ospreys. Why can we make that decision? Lot’s of reasons, and an important one is the easy identification of cause and effect and seeing the return of the eagle over one’s lifetime after DDT was banned. Climate change does not have that easy cause and effect.
Responding to climate change does not have the narrow focus of regulating an insecticide and saving a grand bird. It is not easy to see the benefit of regulating carbon dioxide emissions. Those benefits are many years in the future, and the near-term cost is high. It is like people not taking a medicine that has a 90% chance of curing them from a slowly progressing disease because they don’t understand how the drug they ingest might work; they don’t want to introduce alien chemicals into their body. They seem to be doing okay right now. And if we look at the consequences of climate change, they are frightening, threatening, and they are our fault. We don’t accept fault easily; we have a mandate to feel that we are right. We don’t like change forced upon us, either individually or collectively. We fall back to our beliefs, our identity.
After the blog Rhetoric Again – Cycles, I was asked whether or not I considered man part of nature? Yes, I am saying that man is part of nature. But I don’t think that nature proceeds as a completely unrestrained force. We are many, and we influence nature. In fact, we are at this time the most dominant force of nature. However, we are also able to investigate nature, develop knowledge, and anticipate scenarios for the future. Therefore, we can influence the course of nature. My belief is that we have the responsibility to act on this knowledge. And like people who get caught in cycles of behavior, perhaps trapped by psychological pitfalls, with recognition of our role in nature, we have the ability and the opportunity to take advantage of our knowledge.
To my students I try to teach that they separate what is known from what they believe and what they want to believe. Advocacy needs to be recognized by the advocate, and advocacy changes one's role in decision making. The advocate identifies with an issue and is trying to elevate one position relative to other positions. The convincing advocate for addressing climate change is anchored in a knowledge base that is drawn from scientific investigation. With a separation of what is known, from what is believed to be known, and what is desired based on belief, the climate-change advocate becomes more effective in the decision making process. It is then easier to incorporate climate knowledge into planning and policy and societal response becomes possible.
Updated: 3:28 AM GMT on July 11, 2012