Reference no: EM133616687

Question 

The climate computer models are tested and refined through a process called - , in which simulations are run on a certain model to see how well the model predictions match up to - real-world observations. Scientists have found when - factors are left out of the models and only - factors like solar variability, volcanic activity, and other climate fluctuations are included, the models do a good job of simulating actual global temperature change until the mid-20th century. After that time, both natural and human factors have to be included to match the actual warming occurring, making it clear human factors are driving global warming. current human historical hindcasting forecasting natural.