Here's why:
* Context: The sentence is spoken by the narrator's mother as she is calmly directing the family's response to a swarm of locusts devouring their garden. The locusts are a serious problem, causing a real threat to their livelihood.
* Understatement: The phrase "get the kettle going" implies a casual, everyday activity, completely at odds with the devastation caused by the locusts. It suggests a level of normalcy and composure that is out of place given the situation.
* Ironic Humor: The situation is so dire that the act of making tea becomes an absurdly trivial response. The humor arises from the sharp contrast between the serious nature of the event and the mother's seemingly nonchalant reaction.
In essence, the sentence highlights the mother's stoicism and her ability to find humor in the face of adversity. It also reveals a stark contrast between the perceived importance of the event by the mother and the reader.