The world has been reducing greenhouse gas emissions since at least 1990 when it was 6 trillion tonnes of CO2e per year. We're currently at about 4.4 trillion tonnes of CO2e per year.

We have an ambitious goal of getting down to 1 trillion (or even 250 million) tonnes of CO2e per year by 2050 because of how bad things will get if we don't.

As game theory (and the tragedy of the commons) would suggest, there will be cheaters. But those cheaters are not overwhelming the overall downward trend.