We call this planet “Earth,” although water covers about 75% of its surface. This discrepancy has undoubtedly influenced the way we have historically regarded the world’s oceans: as seemingly endless dumping grounds and inexhaustible sources of seafood and other commodities. As the pernicious effects of climate change exacerbate millennia of abuse, is it too late to save the oceans? Former Globe and Mail environment reporter Alanna Mitchell, author of Dancing at the Dead Sea, asks this question – and many others – in her new book.

The disasters Mitchell enumerates include widespread coastal pollution, bleached coral reefs, acidification, and the imminent loss of wild foods depended upon by millions of people. These problems and their possible solutions are a challenge to describe, but Mitchell’s journalistic skills keep her writing accessible. Each chapter in the book blends lucid, factual explanation of complex subjects with engaging chronicles of the author’s travels to far-flung parts of the globe.

The book’s unrelentingly sombre tone can be tough to stick with. Mitchell notes that other writers feel the need to inject hope into their own doomsday scenarios, but for her the prospect proves daunting until the very end, when she has an epiphany while exploring the dark reaches of the ocean in a submersible (bringing new meaning to the term “rapture of the deep”). As hopefulness floods her, she realizes humans may yet rise to the occasion and turn things around.

Sea Sick’s lack of footnotes and source notes give it a personal feel (albeit with a decidedly scientific and ethical slant). But this lack of analytical rigour will likely be of little concern to popular-science aficionados eager to understand the current predicament facing three-quarters of the planetary surface.