The environmentalists have now decided that the proper atmospheric CO2 concentration is 350 ppmv, to prevent the destruction of the planet. The current level is 390 ppmv, so they think draconian measures to reduce the concentration are justified. How did they determine that the maximum allowable level is 350 ppmv? It seems unlikely they did any logical parametric analyeses to establish that. The Global Circulaion Models have proven to have no predictive competence, so how was the proper level established? I suspect they devined it, perhaps with a soothsayer, or an astrologer. Climate science has about as much creibility as astrology.