Rising atmospheric CO2 concentrations (IPCC 2007) are pushing Earth towards new "greenhouse" states, not witnessed for more than 20 million years. Earth system studies of the ancient greenhouse state of the planet, e.g., during the early Palaeogene (65-35 Ma) and/or Late Cretaceous (100-65 Ma) are therefore becoming increasingly important, and are prominent on the research agenda, as are studies of potential mechanisms underlying the transition to the lower CO2 world of the Oligocene and Neogene, or Icehouse Earth. The first-ever Arctic drilling (Arctic Coring Expedition, ACEX, aka IODP Expedition 302) provided unprecedented snapshots of Arctic climates during the greenhouse conditions, and greenhouse-icehouse transition, spanning the past nearly equal 56 Ma. During times of ultra-greenhouse conditions (i.e., the Eocene Thermal Maxima, ETM, 1 and 2), nearly equal 55-53 Ma ago, our dinocyst and TEX86 ratios records show the Arctic to have been near tropical with temperatures soaring to 24 degrees C. Meanwhile, detailed studies of this event offshore SW Africa (ODP 208) showed the impact of high CO2 in terms of ocean acidification and lysocline shoaling from ancient deep water, tropical settings, while dinoflagellate blooms were raging around the globe. Perhaps even more surprising, at levels dated nearly equal 49 Ma, the ACEX cores yield stunning concentrations of remains of the freshwater fern Azolla suggesting that at least episodically, completely fresh surface water settings characterized the Arctic Basin. Marking the end of the warmest phase of the past 100 Ma, the Azolla event may prove to have been instrumental in the capturing of atmospheric CO2, paving the way for global cooling; a hypothesis currently tested by the 3-PhD Darwin Azolla project. While recording the past, ACEX results may be also taken to portray a possible, "business as usual" future of Earth.