Important to put the numbers in to context. They mention an increase from 0.5% land use for energy production to 3% in their net-zero scenario. It's a significant enough number that well thought out policy is needed, but according to this, 1.7% of the world's land is urban, 7.1% village, 14% cropland, and 26% pasture land. The 3% for energy production is a large increase in magnitude relative to existing energy infrastructure, but a drop in the bucket compared to total human land use (actually much less than I expected). Now add on top of this the fact that a lot the land for renewables will probably be dual use, such as wind farms on cropland, or solar on rooftops or pasture land, and it seems like it's actually quite a manageable number.