Global warming in figures and the question of its treatment: some historical and epistemological views

Abstract: We first recall fundamentals of elementary climate physics: solar constant, radiative balance, greenhouse effect, astronomical parameters of the climate (theory of Milankovitch). Without disputing the analyzes of climatologists and the famous Keeling curve revealing in an indisputable way the increase in CO${2}$ in the atmosphere since the industrial revolution, we nevertheless insist on the main contributor to the greenhouse effect which is, as we know, water vapor. Faced with the difficulties that there will be in imposing zero-carbon policies everywhere in the world (and especially in developing countries), we show that it would perhaps be in our interest to act on soil drought, which amounts, in fact, to being interested in the clouds. The decrease in cloud cover, due to a lack of water fixation in the soil, in fact increases the general temperature and therefore the greenhouse effect. Acting on CO${2}$ will always have, in this context, much less effect than acting on water vapor, even indirectly. Despite the difficulty of making this action sustainable, due to the balance of atmospheric water vapor and the oceans, it would be in our interest not to neglect this path and also possibly increase forest cover for this purpose, given the problems of setting up zero-carbon policy on a global scale. In desperation, one can also consider protecting the Earth with an artificial dust cloud.