'Makes very little difference what we do here in the UK because our CO2 emissions are only 1 per cent of the world total whereas China emits 40 per cent CO2'
China isn't producing these emissions in a vacuum. It's because they have become the 'workshop of the world' - producing stuff for us in the affluent west. Take a look at this vid of historic ghg emissions since the industrial revolution:
One point that becomes apparent is how completely Britain dominated in industrial production until the American war of independence, and this 'prior accumulation' (in Marxist terminology) gave this country huge advantages and allowed it to shape the world to its advantage in ways that are still being felt today. Not exactly a 'minor player' - some of the largest fossil fuel companies are still British, to the extent that global corporations have any meaningful nationality, and thus the UK govt has significant leverage over them, should it ever choose to do so.
Also, it clarifies how the rise of China's emissions coincides with the deindustrialisation of the US and other western powers, which makes sense when you consider that it was in effect a process of shipping manufacturing overseas. All of the same work is getting done (and then some), all of the same resources plus more for shipping, but the profits still disproportionately get channelled to corporations and financial systems based in the west. This gives the lie to the GB News types who wring their hands and pretend that Poor Little UK has got nothing to do with what Big Bad China is doing, and that there's no possible way of influencing them. Easy: stop buying their stuff and they'll stop producing it and shipping it over here. They can start with the nonessential consumer electronics and throwaway plastic toys and work up to the harder stuff...