Sometimes you need both, especially in countries where there's no environmentalist culture and people have too much troubles in day-to-day survival to really ha

Sometimes you need both, especially in countries where there's no environmentalist culture and people have too much troubles in day-to-day survival to really have time and incentive to care about global and longterm issues like ecology or climate changes. In my own experience of growing in one such environment, if you give them just carrots, they'll work really hard to come up with a way to trick the system and grab the incentives while changing nothing. For any change to happen the government just has to push by force for certain baseline rules to be imposed on everyone, and then after some time peoples' mindsets adapt to this new set of rules and they start to play along.