The 20% figure IS too high. True number closer to 6% as per Jon Foley (@GlobalEcoGuy) and even this is misleading because oxygen levels wouldn't actually drop by 6% if we deforested the Amazon. See the longer thread on this w/ @GlobalEcoGuy, @climatedynamics, me & others... https://t.co/bz8eWPHDhC

— Michael E. Mann (@MichaelEMann) August 23, 2019