AQUECIMENTO GLOBAL: UMA VISÃO CRÍTICA

In the last 150 years, the mean global temperature rose about 0,7°C. This increase is being attributed to the enhancement of the greenhouse effect due anthropic activities, such as fossil fuel and tropical forest burning, that emit CO2 – a greenhouse gas, but not the most important one –whose concentration increased from 280 ppmv to 380ppmv in the same period. The hypothesis of anthropogenic global warming was discussed, demonstrating that it does not have a solid scientific basis and it has been established mainly on results of climate computer models (GCM), whose mathematical formulation does not represent the physical processes, particularly the hydrological cycle, adequately. The GCM projections into the future, based on hypothetical scenarios, are mere academic exercises and, thus, their results are unreliable and worthless as far as human welfare and planning are concerned. It is argued that man’s influence on climate, if it exists, is very small, undistinguishable of its large natural variability, therefore, undetectable with present methods. Considering such variability, it is very likely that rather a gradual global cooling will take place in the next 20 years.