Problem is that CO2 concentrations stay elevated basically forever once we dump it into the atmosphere.. This means that the temperature we hit is determined by the cumulative total emissions, not by the rate of emissions. So you can calculate how much we can afford to emit to have a 50% risk of crossing any given temperature threshold, such as 1.5°C or 2°C, between which we lose a lot of major ecosystems, and beyond which we end up outside the envelope where it's clear that we can maintain civilization. This is a very limited emissions budget, so actually keeping temperatures under 2°C means cutting emissions roughly in half before 2030, and to zero by 2050. Since cars last on average about 20 years, deploying new fossil-fuel-burning-cars after 2030 is effectively a commitment to risk ending civilization.
Yes, it's politically tough, but the alternative is to take on a really insane risk.