To global energy supply.
Well, 100% of German scientists who wrote this paper.
The plan: reforest the areas of the world that we deforested with rapidly growing species, then convert the biomass into energy.
They conclude that it is practical and possible to obviate fossil fuels this way, possibly at lower cost than not doing so and to be globally carbon neutral.
They didn't include any analysis of the climate impact of planting so many trees, but it seems likely to be significant.