THE FUTURE AS THE KEY TO THE PAST FOR PALEOBOTANY

Continued increase in the concentration of atmospheric CO2 and its pos sible effects on global climate has generated intense research interes t on the likely responses of terrestrial plants and vegetation. Result s from this new research provide quantitative information on plant fun ction and growth in an environment with a high CO2 concentration, but are also relevant to understanding plant growth in the distant past an d to the techniques employed by palaeobotanists for reconstructing pas t climates from fossil plant remains. Experimental CO(2)enrichment of plants has demonstrated direct effects on leaf physiognomy, the tolera nce of plants to low temperature and the relationship between tree rin gs, CO(2)and climate; it therefore signals the need for caution in int erpreting palaeoclimates from fossils.