Passage Summary: The author argues that we won't solve the climate crisis by just asking people to drive less or turn off lights; individual efforts are too small, so we need government rules to make a real impact.

Conclusion: Attempting to reduce carbon emissions by persuading individuals to change their personal fossil fuel habits is an ineffective strategy.

Reasoning: Even if a majority of people altered their behavior, personal reductions are insufficient to meet the necessary goals, and only government-level policies can operate at the required scale.

Analysis: To find the necessary assumption, we must identify a gap between the failure of 'convincing individuals' and the necessity of 'government policy.' The argument assumes that government policies do not achieve their large-scale results simply by successfully convincing individuals to change their personal habits. If the only way a government policy worked was through the very persuasion the author dismisses, the argument's distinction would collapse. Look for an answer that ensures government policy is not just a more effective version of personal persuasion.