Wind and solar power have grown faster than almost anyone predicted, but projecting their future expansion remains surprisingly difficult. Researchers at Chalmers University of Technology, Sweden, have developed what they call a computational "time machine"—a model that outperforms existing projection methods by using AI techniques to analyze historical growth patterns across countries. Their central projection shows that onshore wind is likely to supply around 25% of global electricity by 2050, with solar reaching about 20%. This is consistent with the 2°C target, but falls short of what is required for 1.5°C. The work appears in Nature Energy.