J. J. Beukema, w. J. Wolff & J. J. W. M. Brouns Man is changing the biosphere at an ever increasing Netherlands ministery of Housing, Physical Planning rate. Several of these man-made changes are on a and Health (represented by Dr. G. P. Hekstra), chaired worldwide scale, such as the increase in atmospheric by Dr. w. J. Wolff (Research Institute for Nature concentrations of several gases. In particular the Management) and housed by the Netherlands In­ ongoing increase of the concentration of at­ stitute for Sea Research (N. I. O. Z. , represented by Dr. mospheric carbon dioxide, by excessive burning of J. J. Beukema). fossil fuels and forest destruction, is well­ The written versions of the presentations by 23 par­ documented. By the year 2050, CO levels will ticipants have been brought together in these pro­ 2 almost certainly be twice the pre-industrial concen­ ceedings of the Workshop. trations and this is expected to have far-reaching consequences. Direct effects include higher rates of The first paper, by G. P. HEKSTRA, explains how plant production (also in agriculture). Indirect effects trace gases affect UV-B radiation, alkalinity of the might be less favourable: by the intensified sea, rate of photosynthesis, and greenhouse warm­ 'greenhouse process' (to which several other gases ing.