Originally published on December 3, 2009
As I was reading the WSJ article today on the new doubts about the credibility of climate science I thought this situation might be analogous to something in the science of economics: the distinction between micro and macro.
First, it is easy to see the amazing advances of science right before our eyes. Science has made the computer and television and cellphones and airline travel and all sorts of other things possible. Similarly, in economics we understand all sorts of simple interactions between households and businesses and governments. We are confident that higher prices will almost always reduce demand, we know that tariffs will reduce imports and benefit domestic industries, and we know that too much money chasing too few goods will be inflationary. This interactions and these simple applications are “micro” in their orientation because they attempt to understand or explain only what is happening in a narrow range. In this micro realm we do pretty well in both science and economics.
However, climate science is “macro” in its focus not micro. Climate science is trying to link together numerous cause and effect relationships and use that to make projections and predictions about our climate 50-100 years into the future. In a similar way macroeconomics takes basic micro principles and tries to explain and predict the complex workings of our domestic and international economy. Economists should have been aware long before the current economic crisis that our predictive power over the economy is extremely limited … that is, unless we assume current trends continue (a brave assumption) and if we don’t try to project very far into the future (not very satisfying).
My point is that economics does pretty well at the micro level. It helps us understand simple cause and effect relationships and can be applied in a variety of helpful ways at a small scale. Similarly with science. However, at the macro level economics fares pretty poorly, not because we don’t understand the possible interrelationships, but rather because it is just too complicated a system to make prediction credible. Likewise then with climate science. The underlying mechanics of the science, that is the micro relationships, may have great consensus in the scientific community, but applying those principles at the global level may be as difficult or impossible as it is in economics.
