Which phrase in this excerpt from kurt vonnegut’s report on the barnhouse effect is an example of sarcasm

Iwould say a but i don’t know what words are underlined

Ascenario where we impact the environment is when humans/ us litter outside or in the ocean which causes wild life to die or even extinct and also if we keep cutting down our trees we might not even have oxygen to live humans also keep limiting water resources wasting it s

Are you asking for a opinion ? if so i believe that a speaker should be genuine and honest about what they're saying and should be factual