This chart is a useful illustration to give a quantitative idea of the relative benefits of different personal life choices. Not everything is on there, and of course the relative importance of medium impact actions in an individual case depends on how much travel, energy and food consumed. However for an average household, most of the things that have the biggest effect on climate change and the attendant environmental degradation are represented.
It is based on research at Lund University: for more detail see here:
The main thing missing I think for a typical UK household is halving heat wasted in the home: but the ‘buying green energy’ bar gives an idea of the relative importance. It’s also important to note that ‘buying green energy’ means buying it from a supplier who only invests in green energy, not just using a ‘green tariff’ – see their full report for their comment on this, which specifically says that on average using ‘green tariffs’ in the UK does not make nearly so much difference as the chart says.
The key conclusion is that, in increasing order of importance,
“The four actions that most substantially decrease an individual’s carbon footprint are: eating a plant-based diet, avoiding air travel, living car-free, and having smaller families.”