Oh dear. Clearly another Arts student who knows nothing about science. First of all the people doing the extrapolating here are your orthodox climatologists. Based on 25 years of data they managed to predict the end of world being nigh....unfortunately had they waited 5 more years they may have realised they were measuring a fluctuation not a trend. In science you observe and collate data, then you hypothesise and formulate typically a set of rules that extend or are based upon your current collection of rules that have been verified over a considerable amount of time by many independent observers. Then you carefully calculate what this means and check the predictions against empirical data. Typically this extension to the rule set predicts something else that can also be measured and verified. There are many example of this in physics. A real science.
Now for all the intellectually challenged Art students like yourself out there here's a quick intro to the scientific method...
<a href="https://www.youtube.com/watch?v=OL6-x0modwY">The scientific method in one minute</a>
In orthodox climatology a bunch of idiots who should have studied English literature rather than science have take a very basic principle and extrapolated from this utter bollocks.