Climate change is a consequence of many interlocking processes, many poorly understood, as a new soil study shows. It suggests that as the proportion of carbon dioxide in the atmosphere rises, the level will be pushed up even further by extra carbon dioxide generated by new activity underground - so-called "soil respiration".

Scientists from the Smithsonian Tropical Research Institute, the University of Minnesota and Cambridge University, carried out five years' research in the Panamanian tropical forest to reach this conclusion. They reasoned that plant productivity and leaf litter would increase with rising levels of carbon dioxide but, to their surprise, plots to which they had added leaf litter showed higher than expected levels of soil respiration.