Perspective in Science
In this perspective we discuss the new paper of Rocha et al. 2018. In this paper the authors use loop analysis to show that positive feedbacks causing ecological shifts may be causally linked. We agree that loop analysis is a nice way to use qualitative information to find possible feedbacks that may lead to critical transitions. However the analysis of Rocha et al. does not show whether the feedbacks are strong enough to be relevant.
Scheffer, M. and E. H. van Nes. 2018. Seeing a global web of connected systems. Science 362:1357. (free reprint here)
Abstract: The Arab Spring, the invention of penicillin, and the recent mass bleaching of coral reefs are reminders that much of the change in nature and society happens in just a tiny portion of time. Understanding why and when such critical transitions happen remains notoriously difficult. On page 1379 of this issue, Rocha et al. (1) mine a database of shifts in social and ecological systems and conclude that about half of them may be causally linked on different scales. Their results highlight the importance of unraveling hidden connections in the web of ecological and social systems on which we depend.