As the model adjusts to these increases, it indicates projected changes in temperature, rainfall, cloudiness, and other climate variables. Climate change cannot be summed up by just a single number. Newspaper reports of climate modelling experiments normally focus on predicted changes in global temperature. But this is a simplification. If model X indicates a smaller warming than model Y, this may be because the two models treat an important climatic process, such as cloud formation, in different ways.
Global temperature is, nevertheless, a useful and important indicator.
Comparing global temperature changes in different models is one way of checking their results. Doubling CO2 provides a useful benchmark, but it does not represent the full extent of the climate change problem. Over the next few decades, however, the rate of climate change will matter more than the total long-term change. But because of the inertia of the climate system, any warming will take place over many decades. Under this scenario, temperatures continue to rise even after the year 2100.