Predicting the future has never been easy, but in this day and age, we have technology to help us find out what to expect “around the next corner”.

In order to understand the future impact of humans on the climate system, we need to calculate the effects of all the key processes operating within the climate system. But the complexity of the system means that these calculations have to be done by computers. The program used for this kind of calculation is called a “model”. The more computer power available, the more complex calculations may be performed.

In order to be useful for modelling the climate, the computer needs to be able to simulate processes in at least both the atmosphere and the ocean. However, a climate model that included all our current scientific understanding of climatic processes would be too large to run on any computer. Instead, simplifications are made to a varying extent. The more nature is simplified, the faster the model can be run or the less computer power is needed.

It is important to note that any computer simulation or model is only as good as the data that are put into it.

Climate models range from the fairly simple to quite complex ones, that attempt to represent climate processes in as high a resolution as possible and with as much detail as available computer power permits.

Simple models allow investigation of basic relationships between the various components of the climate system, the factors that drive climate change and the response from the climate system. Since simple models only include the most critical processes, they are relatively easy to understand and cost effective, so that many tests can be run.

The large models, however, are used for reliably simulating the key processes that determine climate sensitivity and longer term atmospheric and oceanic feedback systems. Results from the large models are often used for simpler models, as well as simulating regional climatic change and variability over short time scales. Large models, though, are costly and require high-resolution data input, which in some cases does not exist, and the results may at times be difficult to interpret, like the climate itself.

Current climate scenario modelling indicates that our environmental conditions will change with increasing speed in the coming years with one of the most significant changes being a warming of the global climate. However, although there will be warming on the global scale there will be large regional variations in climate that will affect various parts of the world differently. In fact, Europe is maybe the most sensitive region of the world and it is not known whether we will experience regional cooling or warming in a future warmer world in general.

References:
Harvey, D. Climate and Global Environmental Change, 2000. Prentice Hall, Pearson Education LTD
EEA Report No 2/2004