Life on land depends on plants. And every plant balances opening its pores to let in carbon dioxide for photosynthesis; and closing its pores to retain water. Graham Farquhar’s work has transformed our understanding of photosynthesis. His models of plant biophysics have been used to understand cells, whole plants, whole forests, and to create new water-efficient wheat varieties. His latest project will determine which trees will grow faster in a high carbon dioxide world. His work has also revealed a global climate mystery. Evaporation rates and wind speeds are slowing around the world, contrary to the predictions of most climate models. Life under climate change may be wetter than we expected. Graham is Distinguished Professor of the Australian National University’s Research School of Biology and Chief Investigator of the ARC Centre of Excellence for Translational Photosynthesis. Graham Farquhar received the $250,000 Prime Minister’s Prize for Science in 2015.