Jag Bhalla in Undark:
The misleadingly presented climate pledges coming out of Davos are but one act in a much larger, intricately choreographed ballet of baloney about carbon removal. The Intergovernmental Panel on Climate Change, for instance, has proposed several climate scenarios that could potentially limit global warming to the target of 1.5 degree Celsius, but every one of them assumes that vast amounts of carbon — between 100 billion and 1 trillion metric tons — will be removed from the atmosphere over the course of the 21st century. Much of that carbon removal is expected to come by way of trees and other forms of biomass through a process called bioenergy with carbon capture and storage, or BECCS.
But research suggests that the planet’s capacity for reforestation is only large enough to remove about 2.4 billion metric tons of carbon dioxide per year. (We currently produce around 40 billion metric tons of global carbon emissions annually, including emissions due to land-use change.) To achieve the lofty IPCC goals, not only would humanity need to rapidly max out the planet’s tree capacity using fast-growth monoculture — potentially jeopardizing biodiversity, current agriculture, and the 7,000 trillion extra calories per year that forecasters think will be needed to feed the growing world population by 2050 — we would also need to augment that tree planting with substantial artificial carbon removal technologies.