Deserts have albedo, and trees sequester CO2. Looking at the first without acknowledging the second is disingenuous.

Here's the view from NASA's JPL [1]. They say the idea has merit. It's obviously not a silver bullet, and any planet-scale project can have lots of unintended consequences, so one needs to proceed cautiously. But one should not dismiss outright any solution because one identifies a negative side-effect.

[1] https://climate.nasa.gov/news/2927/examining-the-viability-o...