"Easy" is irrelevant. The climate doesn't care about which is easier.
The simple fact is that China accounts for 1/3 of total global emissions. If the US went completely carbon neutral today, global emissions would be cut from 38.6 Billion tons to.... 33.7 Billion tons.
If China went completely carbon neutral we'd drop from 38.6 Billion tons to 26.3 Billion.
Everyone needs to cut their emissions. China is actively doing the most damage to the climate, however.