Climate change deniers like to attack the credibility of climate change models. One of the common charges is that 'you can make a model do anything you want.' In this way they are able to fool the public with a false argument. The fact is, models must faithfully represent natural processes, or it isn't a model. I cannot go out and generate some computer code that will give me a desired end result. That is not a model. If I am creating a model then it has to be something that follows the laws that govern what ever it is I'm modeling. In the case of climate change, this would be the laws of physics.
Research scientists creating climate models must write the laws of physics into their code. If done correctly, the researcher can then input a data set and the results will accurately reflect the consequences of that data set. Unfortunately, this is very difficult. The laws of physics on the scale of planetary climate systems is very complicated and has a large number of variables. The good news is that researchers have been working on these models for a long time and are very skilled at what they do. Each new set of models is more and more sophisticated and accurate. In fact, today's climate models are becoming amazingly accurate and produce results that accurately reflect the world's climates. Models today have been able to reproduce past climate changes as well as climate features of today.
It is important that these models are tested and
compared with other models. This is called validation and is the
process of determining just how accurate a model is.Obviously, validation is an extremely important step in modeling. We all need to know just how dependable a model is if we want it to be of any use. That is why climate models are subjected to some of the most rigorous validation of any models anywhere. There is a very good chapter on climate model validation in the latest IPCC report.
Deniers will point out that models are only so accurate and there is still some errors in them. These statements are true, but irrelevant. If we were able to model the climate down to the last atom on the planet, there would still be some errors. What the deniers don't want you to know is that models give us results that are so accurate that we can now use them to make forecasts and their results can be reliably used in policy making decisions.
The real reason deniers don't like climate models is that they consistently and repeatedly show the only way we can have the climate of today is if manmade emissions are factored in. Without gases generated by humans we would have a significantly different climate today. This is just more than the deniers can stand to hear.
But, work is always in progress and I noticed that the National Science Foundation is calling for proposals for new advances in climate models.
I'm sure the deniers will use this as a false argument with the claim that models are so bad the government is vainly trying to find people that can figure out a way to make a better one. Well, don't listen to them. The models are good, but that is no reason to not want to improve them.