When a theory becomes the foregone conclusion among scientists that something is the way they say it is, data can be manipulated, cherry-picked, and misinterpreted (purposely or otherwise) to arrive at the scientist's presupposition. For example, in one case scientists purposely selected three trees that supported their presupposition out of a group of many others.1 This ensured that the data they presented would lead to the conclusion they wanted, and their peers missed or ignored it.
I think you can see the parallels within other areas of science, such as biology, that have accepted a specific explanations and will castigate anyone who questions the status quo. This is evident in the vitriol aimed at those who would promote Intelligent Design as an alternative to neo-Darwinism.
Why does the scientific community become so committed to certain positions? I have a few speculations:
- Monetary: The scientists who follow the status quo are the ones who get the grant money. It becomes essential to their livelihood to support the "consensus".
- Political: There are those who want to advance a political ideology, and scientific conclusions sometimes fuel political decisions that lead to more government control.
- Theological: Some scientists and philosophers are so committed to the belief that there is no God, that they will do anything to advance that idea and bring others into the same line of thought
1 Andrew Orlowski, Treemometers: A new scientific scandal, If a peer review fails in the woods..., http://www.theregister.co.uk/2009/09/29/yamal_scandal/