Indeed that's strange, and the flat slope in 2060 seems inconsistent with declared net-zero policies of China and even India. Russia has no such policy, but still strange to assume continuation of current government concepts there until 2060. (you can see the regional breakdown in supplem Fig 1. )

Uncertainties arise, however, over grid stability in a renewables-dominated power system, the availability of sufficient finance in underdeveloped economies, the capacity of supply chains and political resistance from regions that lose employment.