No I didn't forget meat. Meat production does not directly put carbon atoms into the air (forget methane for a second). That is what I mean by direct emissions. When we decouple energy from carbon, the amount of greenhouse gasses produced by agriculture changes. The problem with such calculations you refer to is that they assume the current rate of CO2 emissions per unit of energy produced/consumed. When we reduce that number to zero, which we will, those calculations are useless. (Farming is a little more complex due to deforestation and methane, but still the argument stands.) This is whats wrong with people who try to calculate MPG equivalents of electric cars based on the current emissions from power production. Electric cars do not release any CO2, period. Power production currently does, but we will fix that separately.
We need to apply system level thinking to this problem, what is a strategy that will lead to zero (acceptable) emissions? We need to focus 100% on that strategy. I believe lifestyle changes based on moral arguments are a distraction due to the following reasons:
1. Its completely unrealistic to change behaviour at that scale
2. Even if successful the effect is only a minor delay, not an actual solution. Any gains due to consumption reductions is more than offset by growth.
3. Focusing on such things may be counterproductive. First by creating opposition to the entire climate change agenda, telling people to change their way of life makes them oppose it any way they can, including denying the problem completely. Secondly we need to stimulate demand for zero emission technologies, reducing consumption is counterproductive to that.