A military approach is called for.
All we have is a couple of decades.
Pulling Carbon out of the atmosphere and putting it back into the ground must take on a high level of priority and operate on a massive scale. Carpeting the centre of desserts with evergreen bushes - e.g. Rhododendron with its prolific growth rate - will provide leaf mass more quickly than trees, while creating an environment for "the bottom end of the food chain".