Energy is the basis of all human activity. It has been, is and will be a motor of social, economic and cultural change. It has been that way since man learnt to use fire in a controlled form. Historically, energy has represented the most evident and palpable relationship between technology, economy and culture. Yet, nowadays most of the big figures and statistics on energy do not inspire optimism. The emissions released from the combustion of fossil fuels are dangerously raising the global atmospheric CO2 concentration and causing smog formation in metropolitan agglomerations to the degree that the planet is warming and cities are drowning. Climate emergency is being declared by states and supra-state political structures as a SOS signal from a civilization in deep environmental decay. A new Energy Transition is on the political agendas of many, but grounding of the civilization survival needs and apparent political will is slow and weak. The worldwide greenhouse gas emissions are still rising and over 80% of energy moving the world is from fossil origin. A paradigm shift of global energetics is urgently needed. At the same time the contemporary city is witnessing a significant change in energy demand patterns as new forms of consumption expand quickly. In the era of global warming and perturbed climate in densely built areas, together with new comfort expectations, the global demand for space cooling is growing at a particularly rapid rate, and projected to grow even more in the coming decades. The demand growth and emissions reduction need represent an authentic energy aporia which fully impacts architectural design. On the other side, for the first time in the history of the architectural profession the climate is not any more a fix condition. For the first time an architect should face the fact that the building to be designed is going to last more than the climate conditions at the moment the building has been designed.