A new study warns photosynthesis could slow with global warning, with forests and plants switching from absorbing carbon to releasing it. Professor Louis Schipper is a soil scientist and Professor at University of Waikato. His research in collaboration with Northern Arizona University, looks at the tipping point for when heat slows plants down and finds it could be a soon as 2040. At that tipping point, photosynthesis would decline, and respiration increase, triggering a disturbance of the delicate balance of carbon sequestration.