"ever" means "of all time, past to present" when used in past and present tenses. Example: "He is the best boxer ever!" (he is the best boxer in all of the past and the present) In future tenses it means "at any occurance in the future", usually used for speculative questions. Example: "Will you ever eat horse meat?" (will you at any occurance in the future eat horse meat?) In present and past perfect tenses it is used to ask questions about experiences. Example: "Had/Have you ever eaten clam chowder?" (Did you in the past at any occurance in your life eat clam chowder?) Never is the contracted form of not + ever (from ne+ever in Old & Middle English). You can replace "never" at any time you want with "not ever" (but it sounds literary or formal) Example: "I will never eat tacos!"(I will not at any occurance in the future eat tacos) "I will not ever eat tacos"(same) "Ever" can mean "forever" or "whenever" in poetry, early modern English or in Biblical scripture. Most people don't know how to use it like this, but we know how to understand it. (Bad) Example: "Doth thou ever loveth me?" (may be grammatically incorrect) "I will ever be in your gratitude"

'ever' in this context means 'in all time', 'until now', 'up to now'. Greta Thunberg is the youngest person in all time/until now/up to now to receive the award. (No one else as young as Greta has previously received the award)

Thanks Brandon

Ever in this sentence is being used as a means to say as far as we know, we being the world as a whole.