While the bulk of the book is concerned with the demise of these historical civilizations, Diamond also argues that humanity collectively faces, on a much larger scale, many of the same issues, with possibly catastrophic near-future consequences to many of the world's populations.

In the prologue, Jared Diamond summarizes his methodology in one paragraph: This book employs the comparative method to understand societal collapses to which environmental problems contribute.

The root problem in all but one of Diamond's factors leading to collapse is overpopulation relative to the practicable (as opposed to the ideal theoretical) carrying capacity of the environment.

One environmental problem not related to overpopulation is the harmful effect of accidental or intentional introduction of non-native species to a region.

Tim Flannery gave Collapse the highest praise in Science, writing:[10] While he planned the book, Diamond at first thought that it would deal only with human impacts on the environment.

... the fact that one of the world's most original thinkers has chosen to pen this mammoth work when his career is at his apogee is itself a persuasive argument that Collapse must be taken seriously.

Secondly, the reviewer claimed Collapse contains some erroneous statistics: for instance, Diamond purportedly overstated the number of starving people in the world.

Jared Diamond's new book, Collapse, confronts this contradiction head-on.Jennifer Marohasy of the coal-mining backed think-tank Institute of Public Affairs wrote a critical review in Energy & Environment, in particular its chapter on Australia's environmental degradation.

[13] In his review in The New Yorker, Malcolm Gladwell highlights the way Diamond's approach differs from traditional historians by focusing on environmental issues rather than cultural questions.

[15] Jared Diamond's thesis that Easter Island society collapsed in isolation entirely due to environmental damage and cultural inflexibility is contested by some ethnographers and archaeologists, who argue that the introduction of diseases carried by European colonizers and slave raiding,[16] which devastated the population in the 19th century, had a much greater social impact than environmental decline, and that introduced animals—first rats and then sheep—were greatly responsible for the island's loss of native flora, which came closest to deforestation as late as 1930–1960.

[17] Diamond's account of the Easter Island collapse is strongly refuted in a chapter of the book Humankind: A Hopeful History (2019) by Dutch historian Rutger Bregman.