“The blue economy”—economic activities associated with the oceans—represents over $1.5 trillion annually and will double in size to $3.0 trillion by 2030. Oceans absorb greenhouse gases and mitigate the impacts of climate change, determine weather patterns and temperatures, serve seaborne trade, provide critical minerals and are targets for offshore wind, nuclear, oil and gas development and more.  And now the blue economy is expanding beyond material goods extraction to knowledge-based activities. What is the future of the blue economy—and why should we care? What is its impact on energy and sustainability? How can we develop the blue economy while ensuring ocean health and sustainability? What is the transition to a knowledge-based blue economy and how can it benefit energy, climate and society as a whole?