Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?

Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?  

Publication Date:  2010-03-30
Creator:  W.F. Ruddiman
J.E. Kutzbach
S.J. Vavrus
Publisher.Display:  Sage Publishing
Subjects.Display:  Climate change
Land use
Agriculture
carbon--isotopes
Source Institution:  Florida International University
Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?