Aquecimento global: pró e contra

A magazine Skeptic, no seu último número, traz dois artigos sobre o aquecimento global: um nega-o (mais precisamente, fá-lo, negando validade científica aos modelos usados pelos climatologistas); o outro defende não só a sua evidência como a origem antropogénica da sua evolução mais recente. Os dois devem ser lidos - o primeiro é bastante técnico (mas não me convence - os modelos nunca valem por si mesmo (valem pela teoria e pela evidência que os sustenta); o segundo é pedagógico quante baste.

1. A Climate of Belief by Patrick Frank

   "The claim that anthropogenic CO2 is responsible for the current warming of Earth climate is scientifically insupportable because climate models are unreliable".

2. How We Know Global Warming is Real The Science Behind Human-induced Climate Change by Dr. Tapio Schneider

   "While there are uncertainties in climate projections, it is important to realize that the climate projections are based on sound scientific principles, such as the laws of thermodynamics and radiative transfer, with measurements of optical properties of gases.

   The record of past climate changes that can be inferred, for example, with geochemical methods from ice cores and ocean sediment cores, provides tantalizing hints of large climate changes that occurred over Earth’s history, and it poses challenges to our understanding of climate (for example, there is no complete and commonly accepted explanation for the cycle of ice ages and warm periods).

   However, climate models are not empirical, based on correlations in such records, but incorporate our best understanding of the physical, chemical, and biological processes being modeled. Hence, evidence that temperature changes precede changes in carbon dioxide concentrations in some climate changes on the timescales of ice ages, for example, only shows that temperature changes can affect the atmospheric carbon dioxide concentrations, which in turn feed back on temperature changes.

   Such evidence does not invalidate the laws of thermodynamics and radiative transfer, or the conclusion that the increase in greenhouse gas concentrations in the past decades is human induced."