Could deserts ever be replenished?

I did not know we were running out of them?

However if you are asking can they be made into fertile regions again the answer is absolutely yes. The process is fairly straight froward.

First keep the goats out, then drip feed some shade plants, introduce underground fauna with the flora and the ground comes back to life while the salts vanish.

Australia has vast inland deserts that could be transformed with sea water with the salt removed, start the greenery growing and work all the way across the continent, fill in lakes and low places with water to bring the water table up, irrigate and drip feed until vast amounts of water gets trapped in biota, the moisture regulates temperature and causes more rainfall. Eventually you get a very nice climate. Kuwait is looking into this process. In truth with solar power platforms running desalination offshore rigs the entire Sahara and Arabian Deserts cold be reclaimed in time.

Actually, they are not in danger of disappearing, but rather growing in size and scope. Desertification is a real problem as destruction of forest habitats reduces the water buffering capacity of large tracts of land. Plants act as living aquifers, holding a lot of water in an ecosystem. Remove enough plants, and you also remove enough water to affect the climate. The key thing that make a desert is not heat but lack of rainfall. In the respect, the amount of land area that qualifies as desert has been steadily increasing over the past few decades. This could be pretty scary, and people worry more about melting ice caps and global warming. Tunr the midwest into desert and see what the world eats!

yes there are seeds scattered all over the place waiting for the right time like rain