Global warming is just the tip of the iceberg (sorry). Seriously though, there are so many ways in which humanity is making the world immeasurably worse and in which our current models of organisation cannot be sustained, and global warming is only one of them. Take for example modern agriculture: we are forced to pour huge amounts of artificial (i.e. not animal manure) fertiliser onto the soil in order to produce en…
But I would prefer an argumentation that does not place the 'artificiality' of modern farming at the fulcrum as there is no 'natural' farming. All farming is artificial - an artifact of human culture. Farming is a thousands of years old biohack, of whose output we've improved over millenias. Using nitrogen fertilizer generated through Haber process to increase crop yelds is not in any way less 'natural' than manure.
Trace chemicals from e.g. pesticides that leak to all sorts of foodchains, including those where human partake - now, that's an issue.
It's also not very effective to speak of the general consumption of western lifestyle. We can't fix 'western lifestyle'. But, we can fix specific problems, one at a time. The problem needs some metric and the solution needs some predetermined metric to follow.
So, what's the first thing you would specifically fix?