Vízügyi Közlemények, 2001 (83. évfolyam)

2. füzet - Szesztay Károly: A víz természeti egysége és társadalmi megosztottsága

216 Szesztay Károly offered by the naturally unified and multi-layered character of water a very important and at the same time a very difficult task. Actually this task is the systematic exploration and rational utilisation of the geographical conditions and socially important properties of water ( Tables 1. and 2.). Its is partially a precondition and partially a consequence of the abundant and continuously renewed supply of water of the Earth that the mean surface temperature of the planet stayed within an extremely narrow range (of about 20 °C), in spite of the substantially changed intensity of solar radiation, and the green-house effects of the atmosphere (Figure 5.). This nearly miraculous temperature stability is maintained by a self-controlling mechanism, which is governed by a high number of internal factors of the Earth, interwoven in a multiple manner with the various spheres of the Globe. The basis of this mechanism is the multivariate stochastic bi-directional relationship between the planetary albedo and the surface temperature {Figure 4.). This multivariate internal relationship of the self-controlling mechanism is governed, in the case of the planetary albedo, by the large-regional-scale variation of the physical state of water and, in the case of surface temperature, the temperature dependent fluctuation of the vapour content of the atmosphere (Figure 5.). An important component of this controlling mechanism is the Bowen ratio, which characterises the composition of the thermal flux from the surface into the atmosphere. The changes of the value of this ratio control the fluctuation of the temperature through the saturation vapour pressure and the relative moisture content (Figure 6.). An important part of the life-centred self-control mechanism of our planet is the ozone layer of the highest layer of the atmosphere, which can retain and convert to heat the biologically harmful ultraviolet radiation, without disrupting the cold-threshold, which latter converts the troposphere into a closed vapour-resen'oir (Figure 7.). In the long term scale of the history of development of the Earth the efficient temperature self-control was secured by the green-house effect, which is governed by the carbon-dioxide content of the atmosphere. Thus the variation of this decisively important geophysical and ecological factor is connected with the processes of the formation and renewal of the rocks (Figure 8.). The first forms of life had appeared soon in this planetary habitat, which is governed by the cycles of water and the control of temperature. Nevertheless, the forming of the vegetation cover, which had launched the full establishment of the biosphere on the continents, was a relatively recent process and is governed mostly by the distribution of the averages of precipitation and temperature (Figure 9.). The most important biological and ecological characteristic of the vegetation is the primary production of organic matter. This latter changes with the vegetation-geographical regions and in function of the annual évapotranspiration and the ratio of aridity/humidity, within very wide ranges (Figure 10.). The continuous temporal variation and spatial fluctuation and shifting of all these vegetation-geographical and plant-biological factors are governed by the changes (of various time scale) of the carbon dioxide content of the air, the precipitation and of the temperature (Table 5.). The water supply and environmental problems of the last few centuries became the decisively fate-forming issue of Mankind: May we continue with the serving of initiatives and objectives, that are absolutely independent of the preceding planetary history: — the self-centred increase of machinery, money and power?? The last part of the study — related to an earlier study of the same author (Szesztay, 2001) — deals with the information-techniques and institutional conditions of integrated water resources management, that could be implemented within the given frames of market mechanisms, in the light of the above question. The variation of the critical threshold values of ecological impacts, which vary in function of environmental interventions, is shown through the example of the water household characteristics of forests (Figure 11.). Since the role of market mechanisms in controlling technological and institutional development is exercised through the dual cycle of the reproduction-at-an-increased-scale and