Maybe the increase of world population is to blame - theres a lot of atoms bound in a human body and all our components come with our nutrition
So maybe the layer gets a bit thicker as human population decreases again
Yeah I once heard Sahara sand is nutritioning the rainforests of S-America and there is even a small desert made out of Sahara sand at the coast.
You have any authority one can have to chase your dreams. I knew I need you when it comes to making inhabitable land habitable.
As I said, once the project goes past "point X", it enters into an spiral of self progress, and everyday its progress becomes faster, here's why:
Imagine Sahara as an example, only few plants (if any) can survive in that piece of hell, since moisture is located toooooooo deep (200 meters depths are not uncommon), and all surface is consisted of 100% dry sand, which lacks two fundamental elements required for growth: moisture and nutrition!
The surface of Sahara gets wet upon each rainfall, and wind carries all kinds of seeds to Sahara each day, but extremely few of them get a chance to germinate, and even fewer survive past the seedling stage, since the moisture content of surface is rapidly decreasing due to evaporation and drainage.
Seeds need surface wetness to germinate, and they must grow deeper roots faster than the rate of moisture drainage to survive.
Once a seed germinates in Sahara, she enters a deadly race with moisture loss, and in order to survive, she must always reach a degree of depth lower than the dryness line, to pump water to higher parts of her body.
Plants who cannot produce deep enough roots, or those who can do it without enough speed, are destined to die in Sahara.
All of that reduces the fraction of seeds (out of total seeds delivered to Sahara by wind) able to turn into mature plants, to a really really low percentage.
Now imagine we cover entire of Sahara with a 30 meters thick layer of pure fluffy compost.
That's a huge brake on the rate of surface moisture loss.
And the percentage of seeds (both in number, and species) able to survive will rise massively.
What happens next, is that the slowly establishing number of plants will protect the surface from compost erosion by wind (sorry Amazon, no more free nutrients falling from sky), and also by providing shade, it decreases the soil moisture loss even further.
And practically, it will be only a matter of time until Sahara becomes a thick tropical jungle on its own.
Fuck! man just imagine that?! we need to produce MORE compost!
Food waste, dead human bodies, all crazy kinds of biomass, we need to turn all of them into remote-dispensable compost, and transfer it to Sahara and similar lands.
Another bonus is:
Besides the huge drop of atmosphere CO2, a jungle Sahara will absorb a gigantic amount of sun rays, and store the energy inside bio-fuel molecules (carbs, proteins, oils, etc), thus preventing the sun energy from manifesting as heat, which will help to balance global temperature even more!
And the synthesize of more bio-fuel molecules, means a greater amount of compost being produced naturally in the jungle, resulting into even less moisture loss rates, which itself results in increasing the number of plants even more!
Folks, it's all an evil loop chain, but it will eventually balance itself, once the global temperature drops enough to prevent plants from growing towards infinite numbers.
So to wrap it up:
All we have to do to save the environment and secure our survival, is to start the loop, then sit back and watch.