Abstract
Energy, water, and food shortages, along with irreversible environmental damage and climate changes, are bound to happen within a decade if the current course of action is maintained, preparing the "perfect storm"-a chain of interrelated events that could lead to major stress on the global system. Energy plays a central role in the complex balance between humankind and the planet: poor strategies for the energy system will lead to disaster; but immediate, radical action can still mitigate what will otherwise be an unprecedented crisis. Reduction of the carbon intensity at the level of primary energy demand is one of the most impactful strategies. Current actions toward this goal, however, including the Nationally Determined Contributions (i.e., the climate actions pledged by the countries that ratified the Paris Agreements), are far from being adequate, and a much stronger effort is required. In this perspective, we draw inspiration from a visionary scientist of the past century, who pioneered the idea of a society powered by solar energy, and show, by a critical presentation of energy and carbon emission data, how this vision is now coming true. We focus our attention in particular to photovoltaics and analyze the factors that make it one of the key energy sources for the short and for the long term: economical convenience, the opening of very large markets, and the push by key players of the energy system.