Significant because temperature changes. Represents only the top layer of the oceans. Cannot do physical experiments for global warming. Need to consider other ways to assess the results of the computer simulations. The most obvious test that could be done to validate the models is to run them for conditions of the past century.
Climate models are still in early stage of development.
Seem to overestimate the amount of warming that will occur. Models are a tool for understanding climate change, but not to a stage where we can have a lot of confidence in the precision of their results.