Global Climate Change
Robert A. Perkins, Ph.D., PE
I have two misgivings in this writing. One misgiving arises from my own undergraduate student experiences in the 60’s, when some of my professors used their authority inappropriately to express their political views to a captive audience. I don’t want to do that. The second is that many of my colleagues are earning both acclaim and money from pursuing research about “global warming.” While I don’t believe this brief web site will endanger their livelihoods, nonetheless I want to avoid Jan Huss’ experience of total body warming.
However some of my students have indicated an unquestioning belief that “global warming” is somehow an enormous environmental problem due to human activity. I realized they have never been exposed to information to the contrary. First I’ll give you links to two resources from scientists much more qualified than I, and second I will summarize my review.
The first resource is:
where you can find a paper, Environmental Effects of Increased Atmospheric Carbon Dioxide. The paper is available for download in several resolutions of pdf and in an html format to the right.
While the first resource is primarily global, the next focuses on the arctic. http://www.iarc.uaf.edu/en/people/sakasofu is the faculty page of Dr. Syun-Ichi Akasofu. At the bottom of that page is link to some of his writings on climate change, here is the link directly Warming.
- The earth’s global climate has always been changing. Here is a chart of the last 3000 years.
[http://www.oism.org/pproject/Slides/img0.html] This chart based on analysis of sediments corresponds to historical records of the Medieval Climate Optimum, when Greenland really was green, and Little Ice Age when all fruit trees in northern Europe died and George Washington’s troops froze at Valley Forge.
- The climate has been warming for about the last two hundred years at the rate of about 1 degree F per century. Between 1940 and 1970 this trend reversed, at least in the arctic, slightly, and then resumed. (With characteristic good luck I was in Prudhoe Bay at about the minimum.) Averaged out, the climate has continued to increase at that same rate. Measuring temperature (which is different than climate) is difficult because of local and temporal variations. Mean sea level is easy to measure and has been measured for commercial reasons for centuries. These have demonstrated a steady 7 inch per century rise for the last 200 years as well.
- Since use of hydrocarbon fuel was not of global significance until about 1940, it is impossible that fuel use or carbon dioxide from it caused any of the historical global climate perturbations.
- The data from the two resources above is based strictly on scientific measurements, not models.
- First let us set right a jurisdictional dispute. “Scientists” attempt to elucidate the laws of nature, “engineers” try to use these laws of nature to design works useful to people. I am always chagrined to find scientists who use models to “prove” something – models don’t prove anything. Modeling belongs to engineers and technologist, not scientists.
- Here is how we use models to predict future events or behaviors based on past experience. We first select parameters, based on our knowledge of the science (physics, geology, and chemistry )of the situation, then link these with a model that, to start with, “predicts the present,” or “fits the data.” The model must fit the data. Once we do that, we vary the parameters according to what we think the parameter will be in the future, or, in the case of time, what it will be. The next step is model verification. We go to the lab this week, or wait a year or two to go to the monitoring well, and then check what has happened. If the model fits the new situation, we develop confidence in the model. If it doesn't, and the client has enough money, we change the model or the parameters and try again.
- ALL the “science” that you read about global warming is based on models, not observed facts. Here are some reasons to doubt the models:
- Akaike and his information criteria. [http://en.wikipedia.org/wiki/Akaike_information_criterion] You can skip the math if you think about it a minute. Akaike says that the more parameters you need to put into your model in order to fit the historical data; the less certain you are that the model will predict the future. All the climate models are incredibly complex, hence very likely “over-parameterized” (as my advisor once said of my kinetic models).
- The climate models, however, do not even fit the present data, at least in the Arctic.
- NONE of the published models that “blame” human activity for the warming trend account for the known historical variations in global climate. The underlying physical drivers of those known historical variations are not known, hence they cannot be subtracted from the current climate prediction models.
- Some not-so-scary scares:
- The recession of the glaciers. Glaciers do not advance or recede because of temperature, certainly not within the small range of the recent temperature variations. They advance or recede because of precipitation.
- The arctic ice is melting. Yes, but it is not melting because of climate change - the changes are too small. There has been a change in ocean currents which has caused more of the thick multi-year ice to exit the arctic. The annual ice, which is completely dependent on temperature, has been increasing slightly in some places, especially the Bering Sea.
- Polar bears are dying. Polar bears and other arctic fauna survived the medieval warming, where it was much warmer than today. The population of polar bears is generally increasing. Here is a video about how polar bears are adopting to climate change.
- Engineering Issues. While the current hype about global warming will play out in the political sphere, there are indeed engineering issues associated with climate change.
- In Alaska we have many areas of discontinuous or “warm” permafrost that will melt if the warming continues. Small changes in vegetation will exacerbate (or ameliorate, who knows?) this trend.
- A sea level rise of 7 inches per century will require some coastal protection. Possibility of flooding will increase in cities that are below sea level or close to it. Certainly caution is needed when putting new infrastructure into low-lying areas.