The changes in weather stations, especially movements and changes in equipment and technology used to measure have made it difficult to measure temperature over an extended period. With increases in population and industrial activities over time, changes in temperature are likely to increase with increased industrial and human activities (Burroughs, 1999).
Positive feedback makes a phenomenon occur. It is when what is expected happens, and increases the initial action. For example, it is commonly assumed that if temperature rises, high temperatures will cause water to evaporate. The vapor will heat up causing a more increase in temperatures. As a result, evaporation will increase, and the cycle continues. Negative feedback makes a phenomenon not to happen and makes it difficult to actualize. For example, when the solar energy causes a rise in temperature, and the earth emits more infrared radiation, the temperatures will reduce and the Earth becomes cooler. When the Earth becomes cooler, the effect of high temperature will fall (Metz, Intergovernmental Panel on Climate Change., & Intergovernmental Panel on Climate Change, 2007).
An increase in global temperature by 3°C will result in a reduction in food production and subsequently low output compared to 1oC. Most areas will suffer drought as a result of fall in rainfall, and many organisms are likely to become extinct. The ice will and snow melt will causing the sea levels to rise (Varotsos, 1997).