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.