The final paper of the Symposium (delivered by Professor Raven) reviewed the rôle of nitrogen in the development of terrestrial life, and gave a timely reminder of the context of the current debate on the effects of anthropogenic N; current man-made perturbations of the N cycle are approaching the scale of catastrophic perturbations caused by major meteorite impacts.

Faced with such a stark evaluation of the current position one is forced to consider how the scientific community is reacting to the challenge of understanding and predicting the effects of man's activities.