Proponents of the wealth tax got a big endorsement from Esther Duflo, Nobel laureate and famous anti-poverty crusader. In a recent gathering of the G20 in Washington DC, Duflo made the case for a  billionaires tax to help bolster global efforts to address climate change adaptation and mitigation in the global south. 

Such a tax, she argues, would go a long way in settling the moral debt that the rich world owes to poor countries who emit very little and yet suffer disproportionately  from the deleterious effects of climate change.

Controversial as it may sound, Duflo’s proposal has the merit of reviving an old debate on the wealth tax by giving it a green twist. Despite its appeal, the proposal is problematic as it does not differentiate between billionaires who made their fortune producing goods and services and those who made theirs rent seeking on nature and harming the climate in the process. 

There is however a better wealth tax, the one inspired by Henry George that would target rentier billionaires who grew rich out of activities that pollute the environment and adversely impact our climate. When combined with a tax cut on climate friendly industries, such a levy could generate the revenues we need for climate action in the global south, in addition to encouraging the emergence of more climate champions.