A Saudi-led group has pledged to plant 35 billion trees across the Middle East — an idea surely everyone can get behind. But what happens when extreme heat makes such projects essentially redundant? That’s the question posed by Haya Alhusainan of the LSE Middle East Centre. Extreme heat therefore “evolves into a persistent environmental condition,” Alhusainan says, and strategies need to evolve. Because if the water runs out due to extreme heat, it won’t be much good having billions more trees.