businesses, NGOs and governments establish the Earth Working Group to to reverse the effects of climate change. Efforts to remove CO2 over the previous decades had successfully slowed polar melting, and while the EWG expanded those efforts, their long term goal was the complete restoration of the Earth's coastlines to pre-anthropic conditions, and a substantial repairing of the biosphere.

To solve the problem, in 2047, the EWG began dredging out the ancient basins of the Sahara desert to serve as a series of inland seas, rivers, and lakes. Similar efforts were made around the world, but Africa would be the flagship project. Autonomous construction robots generated temporary dams and aqueducts to pump billions of tons of water into to the new bodies of the Sahara.



While the waters drained, solar reflectors positioned in polar orbit would restore the remainder of the water to the poles as sea ice and glaciers. Genetically modified organisms would be deposited in and around the new bodies of water to create a usable soil base and reduce the effects of erosion, an effort first attempted by the Great Green Wall project of the late 2010s. Desert would slowly become savanna grasslands and even forests, and the once desolate Sahara would be eroded into three major, but substantially smaller deserts. At the behest of local governments, some of the new harbors created by the rising tide would be retained by dredging out their bases, serving as critical infrastructure to give North Africa a place to ship what would become the wealth of the new Sahara.



EDIT: Due to some legitimate observations about the placement of the rivers, I have amended the map to reflect the actual river layouts of the ancient Sahara:









In 2045 a consortium ofIt had been known for decades that even if Earth's temperatures returned to pre-anthropic levels, the sea levels would never fully retreat. The southern tip of the Greenland Ice Sheet, a remnant of the great glaciers of the last ice age, simply could not be restored without dooming the Earth to another ice age.