Environment Counts | Limiting global climate change requires extraction of CO2 from the atmosphere :
Global temperature has just reached a level similar to the mean level in the previous interglacial (Eemian) period, when sea level was several meters higher than today. Recently the growth rate of human-caused greenhouse gases (GHGs) has increased due primarily to resurging growth of atmospheric CH4, which increases the difficulty of achieving targets of limiting global warming to 1.5â€‰Â°C or reducing atmospheric CO2 below 350â€‰ppm. Based on paleoclimate evidence it has been argued that an atmospheric CO2 level of 350 ppm or larger, if maintained for a long period of time, would push the Earth toward an ice-free state. This paper argues that limiting climate change requires “negative emissions”, extracting CO2 from the atmosphere. It is estimated that with current extraction technologies such as bioenergy with carbon capture and storage (BECCS) or air capture of CO2 this will cost between $104 and $570 trillion this century. Young People’s Burden: Requirement of Negative CO2 Emissions, James Hansen, Makiko Sato, Pushker Kharecha, Karina von Schuckmann, David J Beerling, Junji Cao, Shaun Marcott, Valerie Masson-Delmotte, Michael J Prather, Eelco J Rohling, Jeremy Shakun, and Pete Smith, Earth Syst. Dynam. Discuss., Oct 4 2016.