Its an interesting project. I'm assuming they have taken global warming into account, because this will mean more of the suns rays fall onto the earth. The rays would mostly be in the visible spectrum on their way, and then get absorbed by what they hit (clouds, the solar parks, other parts of the ground, buildings, etc) causing heat, and then being re-emitted (mostly in the infra-red spectrum I assume). Assuming a 33% efficiency of the solar parks, that would indicate around 1500 Megawatts worth of heat extra coming into/onto the earth, per hour. Its not much in the grand scheme of what must already fall each hour on the Earth, but it needs to be considered and accounted for.