"History offers a mixed message about the capacity of humans to innovate and act in time to avoid collapse. At local and regional scales, many multiple past civilizations (e.g., Greece, Rome, Angkor Wat, Teotihuacan) failed to adapt to changing social and ecological conditions and crashed catastrophically. At the same time, human ingenuity and technological innovations allowed the global population and economy to grow at near-exponential rates. This growth has been fueled by exploiting new energy sources, transitioning among animal, hydro, wind, wood, coal, oil, natural gas, nuclear, photovoltaic solar, geothermal, and others. The implications of past localized collapses and global growth are of questionable relevance to the current situation, however, because now, for the first time in history, humanity is facing a global chemical energy limit. The earth-space battery paradigm provides a simple framework for understanding the historical effects of humans on the energy dynamics of the biosphere, including the unalterable thermodynamic boundaries that now pose severe challenges to the future of humankind. Living biomass is the energy capital that runs the biosphere and supports the human population and economy. There is an urgent need not only to halt the depletion of this biological capital but also to move as rapidly as possible toward an approximate equilibrium between NPP [net annual primary production] and respiration. There is simply no reserve tank of biomass for planet Earth. The laws of thermodynamics have no mercy. Equilibrium is inhospitable, sterile, and final."