Welfare is a Stock, GDP is a Flow

I am not exactly sure if I heard him say it in his talk on 6 May 2021 as part of a series broadcasted by the Oxford Martin School, or if I read it in the first pages of his review, but it did provoke a train of thought, Sir Partha Dasgupta’s statement that “Welfare cannot be measured by GDP, since Welfare is a stock and GDP is a flow”.