Historical biomass burning: Late 19th century pioneer agriculture revolution in northern hemisphere ice core data and its atmospheric interpretation

Ice core data from Yukon and Greenland spanning from similar to 1750 to 1950 indicate that between similar to 1850 and less than or equal to 1910 a clear atmospheric signal exists of an episodic biomass burning event that is referred to as the Pioneer Agriculture Revolution, This is best seen in NH4+ ion and particulate concentrations 4 but also in some limited black carbon concentration data, where for all three quantities maximum levels reach about 3 times the prerevolution background concentrations. Tree cellulose delta(13)C data and some early, controversial, French, air CO2 data, occurring within the same time interval, are interpreted as providing other independent evidence for the same, mainly North American, late 19th century biomass burning event, Some hitherto problematic northern hemisphere ice core derived CO2 concentration data may now be interpreted as containing a biomass burn signal, and these data are compared, especially as to the time of occurrence, with all the other results, A global carbon cycle model simulation of atmospheric CO2 mixing ratios using a maximum input of 3 Gt(C)/yr at northern midlatitudes produces ''anomalous'' CO2 levels close to some of the ice core carbon dioxide values, However, other values in this data set do not reasonably represent fully mixed atmospheric values. This suggests that these values might be transients but still ''tracers'' for biomass burning, Nevertheless, it appears possible that interhemispheric CO2 gradients of similar magnitude to the present one could have existed briefly late last century.