 Reviewers also noted the environmental theme in the book . Kirkus Reviews found that " With the impending threat of global warning as an ominous backdrop , teens from very different worlds find they have much in common " . In the novel , Peter finds an underground civilization beneath Greenland that is sinking as a result of global warming . Burns felt that First Light is a " great discussion starter of issues ranging from global warming to <unk> and building a new society " . <unk> recognized the global warming theme and also classified First Light as a coming @-@ of @-@ age tale . 
