Great idea! If there are trees, there would be water and moisture in the air, therefore some life, too. With moisture, there would be clouds and possibility of rain.

Parts of the Sahara were green before (some 5000 years ago), so maybe there is water at some depth below the surface.

Kiprotich Kiptum You can look into the experience of the Inner Mongolia region of China. There is a vested interest by the central government to reduce desertification as Beijing has been prone to dust storms.

During a research trip there in 2004, I remember various projects in Inner Mongolia to combat desertification. I don't know if they were successful, but either way, the projects would give you some insight. Maybe look for contacts at the Beijing Forestry University.

One issue to consider is land use. If you plant trees, how will the community use the newly fertile land? Will it become grazing land? Would there be limits put in place to protect from overgrazing.

Best of luck with your project and please share your experience!

I will follow this interesting discussion and good luck

Thank you Prof. Marazita Prof. Alioua and Prof. Michael for contributing to the discussions.

Already underway with the "Great Green Wall" project across the southern edge of the Sahara desert, several YouTube videos showing the progress. Also see the discussions at https://www.researchgate.net/post/How_can_we_increase_the_success_of_the_rehabilitation_process_of_endemic_water-loving_plants_in_arid_environments

and https://www.researchgate.net/post/How_can_we_increase_the_success_of_the_rehabilitation_process_of_endemic_water-loving_plants_in_arid_environments

and

https://www.researchgate.net/post/How_we_can_reach_the_food_security_in_country_90_is_desert

And visit the project in Tunisia at the Sidi Toui National Park in the middle of the Sahara that is revegetating itself without planting anything, just be keeping the domesticated grazing animals out?

Thank you Prof. Craig for opening up my mind and taking me on a tour to Sahara.

Reforestation on a large scale is perhaps the only method that will fix carbon (sequester carbon) in sufficient quantities to make a sufficient difference to global warming. Also, there is some good scientific and anecdotal evidence that vegetation will indeed alter the microclimate and ameliorate harsh desert conditions. I endorse Craig Dremanns' advice above.

However, recent research such as by Duffy et al http://advances.sciencemag.org/content/7/3/eaay1052 suggests that the rising global temperature will lower the efficiency of photosynthesis and that it may be too late for this technique to prevent accelerating global warming, on a global scale.

But this shouldn't prevent you or any other responsible person from launching projects like those that Craig Dremann has described. They can make a difference locally, even if the long term outlook is pessimistic.

Dear Kiprotich Kiptum

Its chalanging but still possible

sellecting the right plant species will save the time, mony and efforts.

Geoff Edwards --"When there is still life, there are still possibilities." Would you give up on a relative in the hospital, just because she needs some medical care? We have put the arid grassland-savannah habitats of our planet into critical care in the hospital from the abuse of our grazing animals, so we cannot give up on Momma Earth, just because we have a huge medical care issue to do?

Actually trees contribute very little soil carbon sequestration, it is the grassland savannah that is doing most of that job, and in utilizing the native perennial grasses, then the carbon you sequester will be put away for thousands of years instead of hundreds of years.

We need to look at ALL of the native plants in an area, like the deserts of the world, and do a radiocarbon dating of the soils, to see how long each plant put that carbon away in the soils.

And while we are looking, also look for the native Pseudomonas host plants that create the rainfall for that area, and plant those back to increase the rainfall for the native plants that we want to cover the barren soils.. See https://www.discovermagazine.com/planet-earth/does-rain-come-from-life-in-the-clouds

The current barren desert areas of our planet are perfectly positioned to be the carbon sinks we need, to replant those areas with their local native plants, and get the carbon soil cycle restarted again, that our domesticated animals started unplugging 5,500 years ago?

And since the countries producing carbon will need to buy carbon credits to reach their goals of being carbon-neutral by a certain date, within a decade or two, then the deserts of the world become more valuable when you use the native grasses to produce those credits, instead of feeding them to goats, sheep and cattle.

Plus, if you look at this plan from a business perspective, have the local people doing the grazing, produce a business plan? They calculate after expenses, how much net income do they produce each year, and then divide that income by the number of hectares they graze, to calculate what grazing one hectare actually brings home?

Then, if you left the grasses to grow unmolested, how many more times net income could you produce? For our western US deserts, I am calculating that selling carbon credits could produce from 10 times the take home net income to maybe 25 times.

The Global Warming issue is insignificant, compared to the local people not utilizing the desert grasses to produce the maximum income, and wasting it on grazing animal feed, instead of leaving those plants to grow unmolested and selling the carbon credits for a multiple of what they are worth as feed?

Plus, by maintaining a barren desert by continual abuse, does not make any sense, when you can see from the example of the National Park in Tunisia, in only 10 years, you can go from a barren Mars-like landscape, and produce a much better living habitat for all?

Let the countries that need those carbon credit, pay for the restoration of the entire Sahara desert, and it could be the perfect carbon sink for both Europe and Asia?

Picture from Oman, when you have the native vegetation around Salalah and when you do not, from https://www.ecoseeds.com/cool.html --My work on how to cool the planet with native vegetation

Thank you Craig Dremann for that extra explanation. I agree with nearly everything you said and commend your response to Kiprotich. Communities everywhere should do everything in their power to sequester carbon, particularly given that governments are so slow to commit to adequate responses.

I particularly agree that grasses have a much greater potential to store carbon than trees. Please refer to my colleague Alan Lauder's very readable explanation of "carbon stocks and flows" at http://www.royalsocietyqld.org/carbon-stocks-and-flows/ and his explanation that graziers must spell their pastures after rainfall events, to allow the grasses to replenish their root systems. He has explained that it is the flows of carbon that energise a landscape but the flows are difficult to measure. The stocks of carbon such as held in tree trunks are easier to measure, so tend to be the basis of world trading schemes, but they don't bring a landscape to life as much as the flows.

I fully agree that removal of grazing stock is a necessary precondition to regeneration of arid landscapes and that even if grazing is to continue, pastures need spelling to allow root systems to restore biomass to the soil.

The one point that I question is about the effect of global warming. Already in Australia the average temperature is 1.4° C above the long-term historical averages. This has large implications for evaporation, transpiration, timing of flowering, survival of insect populations et cetera. The global warming that is already locked in will have big implications for how we manage our semiarid and arid environments. However, I fully agree that large-scale regeneration is necessary and urgent and worth pursuing and can make a difference locally, even if the overall outlook for humanity is gloomy.

Thank you all Prof. Edwards, Omar and Prof. Craig for your contributions. My worry now is that with the COVID-19 pandemic such efforts might be cast aside for the time being.

Regeneration can be labour-intensive and can soak up labour that has become unemployed because of COVID-19. However to mobilise it requires competent government that is willing to abandon neoliberal opposition to public budget expansion.