school energy&environment

Future IPCC scenarios

In the past 20 years scientists have researched calculation models which try to foresee climate variations. These models are known as GCM (General Circulation Models). Some IPCC studies have been able to foresee four possible future scenarios (A1, A2, B1, B2), by taking into consideration population growth, economic development, available resources (meaning primary energy sources) and technology. These hypothetical evolutions are called “scenario families”.
A1: this scenario family foresees a rapid economic growth, the population will continue to increase until 2050 to begin decreasing after that and there will be a rapid introduction of new more efficient technologies. This family develops three groups that describe alternative directions for technological development in the energetic system: A1FI a future with fossil fuels, A1T non fossil resources, A1B a balance between fossil fuels and other sources.
A2: This scenario foresees a very heterogeneous world. There will be a constant demographic increase with very slow and irregular pro capita economic growth and technological development.
B1: This scenario as well foresees that the demographic growth will continue until the middle of the century to then start decreasing, but there will be a fast change in the economic structure towards an economy based on information and services, with a reduction in material use and the introduction of clean and efficient resource technologies, in other words there will be a sustainable kind of development with limited use of resources.
B2: The population will continue to grow but at a slower rate compared to the A2 family, the economic development will be average and technological changes slow and differentiated but always aware of  sustainable development.
Each scenario is supposed to have different levels of carbon dioxide emissions for the period ranging from 1990 to 2100.
The main changes pointed out be the models besides the increase of greenhouse gas concentration in the atmosphere are the following three:

• Global warming of the lower atmosphere and the planet’s surface;
• Acceleration of the water cycle in the atmosphere and the ground;
• Sea level increase.