Drop in the ocean.
Whatever anyone does the earth is now warming at the rate of 1.5C every 100 years. And unless China and India adopt CO2 controls nothing is going to change, even if the UK or even the USA produce zero CO2. I read that even if the Paris climate accord had been fully implemented, it would only have delayed CO2 level increases by 5 years.
So CO2 levels are going to climb, and if there are to be impacts, we'd be better off focusing on mitigation and investing in things like hydrogen fuel cell vehicle and infrastructure technology. (Lithium carbonate is a finite resource and there aren't enough current reserves on the planet to meet demand).
There's an awful lot of bull**** talked about climate change and how to get to net zero emissions, but unfortunately not an awful lot of thought about how to achieve the targets. Like the policy to get to net zero by 2030 (or 2050 for that matter), even though that would mean much of the population would have to give up their vehicles.