Would a mive world-wide afforestation project help alleviate global warming?

Photosynthesis is nature's efficient way of recycling atmospheric carbon dioxide. My enquiries reveal that we do not as yet have the capability of artificially emulating this process to any degree of efficiency. So why not ist nature do the job on our behalf by engaging in MIVE AFFORESTATION PROJECTS THROUGHOUT THE WORLD? Major carbon polluting countries like the USA, Australia, India and China and a major forest-depleting country like Brazil all have the resources to carry out such projects and also ist poorer countries elsewhere, especially in Sub-saharan Africa, do the same. Even if it later turns out that global warming after all is not solely due to human over-consumption of hydrocarbon fuels, we would at least have acted on the side of caution. In my estimation, the planet would only be better off with more vegetative cover, not worse off.