Saturday, March 8, 2008

Climate Modeling and Economic Development

Once in a long while I see something written on the internet truly thoughtful and insightful. Even more rarely, such thought and insight appears in a blog discussion. The following comment on climate modeling, by a gentleman named Ajit from Sunnyvale California, appeared on the New York Times website on a blog discussion on the recent climate change skeptics conference held in New York (I have highlighted what I believe to be his most salient comment):

Back in the early 90s, when I was a fresh PhD looking for a new area for post-doc research, I checked out the area of climate modeling. I saw a lack of high-caliber research, particularly in the experimental areas (e.g., cloud formation). Many climate modelers appeared to me at that time to underplay the uncertainties in their models. I was not impressed. The final straw was attending a talk by Stephen Schneider who had just arrived at Stanford as a faculty member. The talk sounded to me like a political speech with little discussion of the technical aspects, even though he was addressing a group of researchers.

Things appear to have come a long way in the last 15 years, and everyone feels sufficiently qualified to make sweeping statements about climate change that should make the average model developer shudder. The accuracy of climate models is determined not by doing experiments, but by taking a poll amongst climate scientists and modelers.

For example, I watched David Letterman having a discussion on climate change on his show with Tom Friedman with the former crediting Al Gore with teaching him all about it! It was comedy at a level that John Stewart would appreciate!

What I find strange is that there is no discussion is to whether the technical problem of climate modeling (as opposed to weather modeling) is solvable. I do not mean whether we have the necessary computing power. I mean whether there are at all any unique solutions to the complex and highly coupled set of partial differential equations that describe the thermo-fluid transport process governing climate behavior.

To give an example, consider the problem of free convection of gas between two concentric spheres with two different constant temperatures imposed on the sphere surfaces. The flow patterns that develop depend on the initial guess values one assigns to the gas velocity and temperature, i.e., the solutions are non-unique. We are talking about simple laminar flow here, not turbulent flow with chaotic phenomenon that occurs in the atmosphere and makes the solution even less certain. It is just the nature of the mathematical problem. Once can draw an analogy between this flow and that of the atmosphere. I fear that we have little chance of making long-term accurate projections if this simple problem has non-unique solutions.

By contrast, weather modeling for predictions over a week or two are much more accurate because the models are data-driven and the uncertainties don’t accumulate over long periods. Even then, try doing the experiment of comparing two-week predictions of temperature and precipitations in your area with actual data.

Of course, climate modelers have a vested interest in not talking about such issues. But we can start by comparing the predictions of today’s temperature and flow fields with those predicted by models 15-20 years ago, and continue to do so in the future.

The increase of greenhouse gases point to a warming trend. However, we are not sure what the nature of the feedback (positive or negative) that is introduced. Additionally, the range of average temperature variations we are shown as proof of global warming is comparable to the magnitude of the measurement noise. Basic scientific practice dictates that such data not be used to come to major conclusions that drive public policy.

In other words, I don’t think I will feel comfortable tens of millions of poor in India and China that we have to go slow in improving their lot so that a thousand Pacific Islanders are not displaced. I would also go slow in extrapolating a rise of a few centimeters of local sea levels to a rise of meters at key population areas for the convenience of fear-mongering.

The writer addresses the most important issue in climate modeling - modeling the climate is not the same as predicting the climate in 100 years. Systems such as the earth's climate are complex, that is, the number of possible outcomes is so divergent and the probabilities of these individual outcomes so small that that predicting which path the general climate will take over the next 100 years is simply heroic.

Below is a response by another reader to the comments of Ajit. I will save my comments for later. Enjoy the unfiltered thought by someone calling themselves mhoney:

dear Ajit in Sunnyvale

Unfortunately, it is the millions of poor in India and china who will suffer first and most from global warming - you have that backwards. Have you not noticed the extent that Beijing is going through to try to get their air to acceptable standards for the Olympics? And we’re not even talking LA standards - it is way worse than that!

It is not a question of progress versus no progress. The new direction technology takes needs to include these millions of poor - we cannot leave them with belching smokestacks and fish-free waters. They are ‘developing’ using 20th century technology - not the techonology of our grandparents, so the scale is not comparable, either. To say that a few centimeters of rising waters in a pacific island should be contrasted to with raising millions of poor out of poverty through ‘progress’ certainly ignores the price of that ‘progress’ the poor are already paying. The ‘third world’ should be first in combating global warming - they are already suffering the most.

Oh, really? I remember the first time I went to China in 1992 as part of a party from Japan that were guests of the provincial government of Fujian. One of the places we went to was a fairly remote city in the province's interior. I remember leaving my hotel one evening to stroll around the city. People stared at me as if I were an apparition - it was as if they had never before seen a white face. And perhaps, I thought, maybe they hadn't and that I was truly that first white face. I could see that people weren't starving, but I could also see that their bellies weren't full. But I could feel a furious energy in the people, a furious desire to improve their lot.

This person has the temerity to say that the millions of poor in China and India are the first ones to suffer from global warming. What on earth is this person talking about? Yes, these people are breathing foul air. It's not perfect, but it's a whole lot better than the world they were living in when their air was pristine. While this person makes the good point that these people should benefit from emerging energy generating technologies, the unstated premise here is that poor people in countries like India and China should just be patient and wait for the developed world to bestow upon them advanced technologies which will, naturally, fit perfectly into their own developing economies. Trust us, we have everyone's best interests at heart here.

Unfortunately, the developed world never gives anything away for free. Countries that have control over their destiny are countries who have control over their economies. That is, their economies are structured to be compatable with their culture and their trade and inward foreign investment relationships with other countries are structured with their own national interests in mind.

These two comments sum up the most important issues regarding climate change. Predictions of potential disaster are based on models that cannot predict the future no matter how much computational power the computers have and no matter how accurately the physical phenomenon being simulated are modeled. Belief in the outcome of these models is an act of faith. Unfortunately, those that take the model's results as an act of faith then use these results to make policy prescriptions with potential impact on the lives of everyone. That the vast majority of people making such policy prescriptions reside in developed countries should suggest that such "solutions" have the best interests of the developed world at heart.

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