You can also see my profile at https://mewe.com/i/thomasmiller13
Also see vpdau.blogspot.com
FREEWARE Delphi 2 water from air code at
https://airartist.blogspot.com/2019/09/water-from-air-delphi2-code.html
For hot arid regions one could start with humidifying an area along the coast, using coarse shade cloth hung vertically above the waves. Then plant a green wall of trees, from the humidified area, to the interior of the country. Along the great green wall the relative humidity will be higher, the temperature will be lower, and the vapour pressure deficit will generally be better than that of the surroundings. The green wall will help humidify the interior and enhance plant growth.
Humidification at the coast could mean humidification of the interior - see https://eos.org/articles/heat-waves-are-blowing-in-the-wind
Note that whole economies depend on the sale of oil and gas and it is unlikely oil and gas sales will stop in the near future. While I agree on the need to reduce the use of fossil fuels it seems to me that we need a temporary solution that involves the humidification of land and the growing of vegetation there. Oil and gas production is steaming ahead - see
https://www.forbes.com/sites/rrapier/2018/09/14/oil-will-remain-a-large-viable-industry/#5bad61262d3d
Crops need more rain when relative humidity is low and when wind speed is high - see http://www.fao.org/3/s2022e/s2022e02.htm So building windbreaks and humidifying the air will reduce water needs.
Links:
See https://en.wikipedia.org/wiki/Great_Green_Wall and
https://www.sciencedaily.com/releases/2019/08/190830112813.htm and
https://phys.org/news/2019-09-forest-loss-brazil-contributing-temperatures.html and
https://www.facebook.com/Vapour-Pressure-Deficit-104605390919823/
For information on vapour pressure deficit see https://en.wikipedia.org/wiki/Vapour-pressure_deficit
You can download my free instrumental tune "Sail Cloth" that could remind people of the coarse sail cloth above the waves idea. Download free at https://clyp.it/l3oanx0t
Another global warming instrumental tune I composed can be downloaded free at https://clyp.it/v0saxl3v
NOTE: Regarding shortage of water, the growing population requires more water and overpopulation is a problem. Population campaigns tell us that many people become impoverished because of lack of family planning - see https://www.pbs.org/wgbh/nova/worldbalance/campaigns.html
Coastal air can be humidified by hanging coarse shade cloth vertically above the waves to catch spray. Wind blowing through and around the shade cloth will be humidified. Wind blowing over the shade cloth will lift spray high in the air, thus causing greater evaporation. Humidification will reduce vapour pressure deficit (VPD) in dry areas. Humidification at the coast will help humidify regions inland (by means of sea breezes, etc). Also see my profile at https://mewe.com/i/thomasmiller13