Seaweeds (macroalgae) are, together with microalgae, main contributors to the Earth’s production of organic matter and atmospheric oxygen as well as fixation of carbon dioxide. In addition, they contain a bounty of fibres and minerals, as well as macro- and micronutrients that can serve both technical and medicinal purposes, as well as be a healthy and nutritious food for humans and animals. It is therefore natural that seaweeds and humans have had a myriad of interwoven relationships both on evolutionary timescales as well as in recent millennia and centuries all the way into the Anthropocene. It is no wonder that seaweeds have also entered and served as a saviour for humankind around the globe in many periods of severe needs and crises. Indeed, they have sometimes been the last resort, be it during times of famine, warfare, outbreak of diseases, nuclear accidents, or as components of securing the fabric of social stability. The present topical review presents testimony from the history of human interaction with seaweeds to the way humankind has, over and over again, been ‘saved by seaweeds’. It remains a historical fact that in extreme conditions, such as shortage and wars, humans have turned to seaweeds in times of ‘needs must’ and created new opportunities for their uses in order to mitigate disasters. Lessons to be learned from this history can be used as reminders and inspiration, and as a guide as how to turn to seaweeds in current and inevitable, future times of crises, not least for the present needs of how to deal with changing climates and the pressing challenges of sustainable and healthy eating.

海藻（大型藻类）与微藻一起，是地球生产有机物和大气氧气以及固定二氧化碳的主要贡献者。此外，它们还含有大量的纤维和矿物质，以及常量和微量营养素，可用于技术和药用目的，并且是人类和动物的健康营养食品。因此，海藻和人类在进化时间尺度上以及近千年和几个世纪一直到人类世之间有着无数相互交织的关系，这是很自然的。难怪海藻也进入并成为全球人类在许多严重需求和危机时期的救世主。事实上，它们有时是最后的手段，无论是在饥荒、战争、疾病爆发、核事故时期，还是作为确保社会稳定结构的组成部分。本专题评论提供了人类与海藻相互作用的历史的证据，以及人类一次又一次“被海藻拯救”的方式。历史事实是，在短缺和战争等极端条件下，人类在“必须”的时候转向海藻，并为其利用创造了新的机会，以减轻灾难。从这段历史中汲取的教训可以作为提醒和启发，并作为在当前和不可避免的未来危机时期如何转向海藻的指南，尤其是满足当前如何应对气候变化和气候变化的需要。可持续和健康饮食面临的紧迫挑战。