 The hierarchy of accumulating physiological knowledge , from single  to multiple drivers, and from simple outcomes , interactions among drivers  and identification of physiological roles of drivers  to mechanistic understanding of drivers . At present, the upper grey layer has been achieved, in full, for two drivers , with validation of dual controls on phytoplankton growth rate . Hatched layers denote major advances since WGII AR5 Chapter 6 . The green layer indicates the level of understanding potentially needed to project the response of marine life subjected to multiple drivers. Red horizontal arrows indicate the influence of confounding factors on our current understanding, including population genetics, fluctuating oceanic conditions or extreme events.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report