Photosynthesis is the basis of all life on earth, the foundation of civilization, and the ultimate driver of the global economy. It is a complicated process with many steps, influenced by myriad factors. But we now understand it well enough that we can imagine many ways to make it more efficient, more productive, and tailor it to meet human needs. Recent advances in recombinant DNA technologies, including gene editing, give us the tools to do so, and many researchers are applying them with promising results. These offer many opportunities to help mitigate climate change, while also promising to re-shape virtually every aspect of the relationship between humans and the environment. The implications are so enormous that all but a few science fiction writers have underestimated it.