Sometimes you can't see the forest from the trees but spare a thought for the wilderness beneath the waves. Kelp forests are found in shallow ocean waters off a third of the world's coastlines, and, according to new research are worth hundreds of billions of dollars to society. Marine ecologist Dr Aaron Eger led the study and is also the founder and director of the Kelp Forest Alliance – a research-driven not-for-profit dedicated to accelerating the protection and restoration of kelp forests worldwide. Today he's on The Green Desk to discuss his work putting a dollar value to the kelp forests below the sea level.