There is a general agreement among scientists that the surface temperatures of both oceans and continents are rising. It is also agreed that greenhouse gases like carbon dioxide and methane are increasing in the atmosphere and that this increase is a result of the continuous rise in human industrial and transportation activity, depending on the fossil fuels, i.e., coal and petroleum. There is still an ongoing debate whether all three phenomena are interconnected and whether part of the blame for the warming should be apportioned to natural processes, such as those that caused climate changes before the industrial revolution. The majority of scientists will not contest natural processes as a possible additional factor but will put the main blame on the emission of greenhouse gases, while admitting that there are some questions which still remain to be solved: such as what is the cooling effect of other products of industry emitted into the atmosphere (e.g., smoke and sulfurous particles, which may cause a shading layer with a cooling effect).

One of the most important tools for investigating the reasons for the global change, as well as for predicting future developments, is computerized general climatological models (GCM), which simulate the physical processes taking place in the atmosphere and beyond, and their impact on the temperatures of sea and land. However, as with all computer models, the correct output is a function of correct input, when input in this case involves data as well as procedures.