Conventional biomass sources have been widely exploited for several end uses (mostly food, feed, fuel and chemicals). More unconventional sources are continually being sought for meeting the growing planetary demands for biomass materials. Biofuels are already commercially produced in many countries and are becoming mainstream. The role of biorefineries for production of chemicals is also on the rise. Plant biomass is the primary source of food for all multicellular living organisms. Primary production remains a key link in the chain of life support on planet Earth. Is there enough for all? What new strategies (or technologies) are available or promising for providing plant biomass in a safe and sustainable way? What are the potential impacts (footprints and efficiencies) of such strategies? What can be the limiting factors—land, water, energy and nutrients? What might be the limits for specific regions (OECD vs. non-OECD, advanced vs. developing, dry and warm vs. wet and cool, etc.). In this paper, we provided answers to these questions by critically reviewing the pros and cons associated with current and future production and use pathways for biomass. We conclude that in many cases, the jury is still out, and we cannot come to a solid verdict about the future of biomass production and use.