With current rate of global warming, conventional emission reduction method is not likely to limit the amount of global warming to a safe level we expect. Alternative climate intervention methods including carbon dioxide removal (CDR) and solar radiation modification (SRM) are gaining increasing attentions. CDR aims to intentionally reduce the amount of atmospheric CO2 by enhancing the oceanic and/or land carbon sink, or direct removal of CO2 from the atmosphere. A deep understanding of the geophysical processes in response to CDR and associated negative emissions is the key to understand possible climate and environmental consequences of negative emissions.

In this talk, I will present results from Earth system modeling studies that analyze global climate and carbon cycle response to some proposed CDR methods, including ocean iron fertilization, ocean alkalinity enhancement, and direct atmospheric CO2 removal. The focus will on the analysis of the underlying physical, chemical, and biological processes associated with climate and carbon cycle response to negative emissions.