How much of uncertainty about global warming?

Abstract

The paper presents in a half-popular form the definitions of the „greenhouse effect” and the „global warming”, as these concepts in Polish public language and in media happen to be confused one with another and sometimes wrongly labelled as politically driven by the leftists. Based on the world literature the mechanisms of these climatic phenomena have been explained, and recent global increase in temperatures presented as a fact. The evidence in favour of a significant anthropogenic contribution into greenhouse gases emissions has been shown to be accumulating, even in the Southern Hemisphere. A support for Ruddiman’s hypothesis about possible human contribution to medieval and “little ice period” climate fluctuations has been found in the changing forestry policy and dramatic postmedieval collapse of human population. It is argued that carbon sequestration ability of overexploited very young (4-8-year-old) coppice and pastoral woods had to be several times (5-10 times) lower than that of the more extensive and much older 17th-18th century forests (coppice-with-standards, plantations, middleaged wood). At present some uncertainty remains only in what proportion the humanity contributes to climate change, as well as if, or for how long, the present warming will progress. Facing such fairly small uncertainty with currently predominant explanation the Precautionary Principle must be adopted, as the only rational approach. Therefore, we all and our countries have to reduce own contribution to the greenhouse emissions by changing the technologies and the way of life in several its aspects.