Together, China and the US emit about 35% of today’s greenhouse gas emissions. Current global climate change action is insufficient to limit warming below 2°C. By improving action of China and the US to global best practice, these two largest emitters could decrease domestic emissions to a level compatible with 2°C and together close 23% of the 2020 emissions gap. For 2030, this would mean a decrease in emissions below current global policy projections by 10%.