Mann's "question" is one of those "it's not really a question it's more of a statement" kind of questions. He begins You’ve said you don’t know the solution for the politics of climate inaction and also that we need a “miracle” to address the climate crisis. But the obstacles aren’t physical or technological at this point (my bold).
To understand the question you need to know that Mann is referring to Gates in 2016 - which is odd in itself; a lot has happened in six years - and that the word "miracle" doesn't have its conventional meaning of something requiring divine intervention; indeed, it has pretty well the oppostive meaning: of something that is quite likely to happen (another example of a miracle according to Gates is the polio vaccine). Mann continues "The only real obstacle is having the political will to invest adequately in those technologies and put in place market incentives that accelerate the needed clean energy transition".
Gates's answer It’s weird to have… I mean, how do you think we’re going to make steel? How do you think we’re going to make cement? Most of the emissions are from middle-income countries. And the ability of either asking them to bear the huge premium and cost of clean approaches, or asking rich countries to subsidise that, that collective action problem is not likely to be solved with current green premiums. So it’s almost like he doesn’t acknowledge all the different sources of emissions. That’s weird... I don’t understand why he’s acting like he’s anti-innovation also seems off point to me, although consistent with his previous opinion that we do need FutureTech. I think there are three position: A: we can and will solve GW with TodayTech; B: we could do that but actually we'll use FutureTech at least in part; and C: we need FutureTech. I think B is correct; Mann is too much on A, and Gates on C. And Hossenfelder has misread everyone (Mann isn't saying it is simple-cos-we-have-tech; and Gates isn't saying the problems are primarily political).
Which is uncannily a replay of Half of emissions cuts will come from future tech, says John Kerry. And Mann, there, was again saying "no, we'll use current tech". Mann's point, I think, is "lack of tech is not the problem, and waiting for FutureTech is a bad idea", which is true, but uninteresting at least to me, because everyone agrees... although Gates manages to give the impression that he doesn't: there isn't a huge premium to clean tech; solar is competitive in a great many places. Mann's assertion that the problem isn't "physical" is doubtful; part of the problem is indeed the vast amounts of existing physical infrastructure.
Gates, oddly, makes no reply on the "political will" part. Perhaps he just hates politics and doesn't want to talk about it - many tech folk do, for the obvious reasons - and is counting on tech to solve the problem. Which I think it will, if the pols don't fuck things up too badly.
Score: Mann loses points for a badly phrased question; and for failing to analyse Gates' reply, but Gates loses more for getting the wrong answer.