herm the milankovic cycles are 3 as far as i am aware ibrahim

anyway many defenders of the gaia theory state that before the sahara returns to being a savanah we will undergo a new ice age so those thousands of years you speak off mean alot of trouble and storms ahead because the increase heat will increase evaporation and create thicker and more permanent clouds that will cool off the earth (then i bet we will be bitching at the envirementalists and will try to burn as much coal as we possibly can to warm ourselfs in our subway tunell houses 20 meters under the snow \o )

anyway the practices you speak off being made in arabia and the levant have shown they are not effective on the long term and are very weak during extended droughts period however the chinese seem to be able to use them extremly effectivly to stop the gobi so maybe with a new nile damm proper use of the aquifers and the rain from the atlas range combined with true political goodwill and proper planing "might" turn the tide but until there the sahara will continue to grow in all directions forcing africans to go further south wich will increase the migratory pressure from gana nigeria somalia and such towards europe (in some ways the same can be applyed to marocans tunisians and argelians not lybians tough they have the money and the water to resist for a few more hundread years)