The Cretaceous Period serves as a relevant model to understand greenhouse climate evolution. As atmospheric CO 2 concentrations continue to rise in the twenty-first century, critical questions put forward are 1) how the Cretaceous Earth System could have been maintained in the “greenhouse” state, if there are some variations, 2) why and how fast did climatic and palaeoenvironmental changes happened during the Cretaceous, and 3) what records were preserved in the Earth's archives that enable the comparison of Cretaceous rates of paleoenvironmental changes with today's global changes. In fact, rapid and severe global environmental and climatic changes happened in the Cretaceous greenhouse world including oceanic anoxic events, oceanic red beds, “cold snaps” or glaciations and carbonate platform drowning events. This special issue originated from the final workshop of UNESCO International Geoscience Program IGCP 555 and the Pardee session of the Geological Society of America 2010 annual meeting. Participants and contributors mainly focused on the causes, processes, and consequences of rapid environmental/climatic changes that happened in the Cretaceous greenhouse world.