The echoes of the earliest human-caused carbon emissions are still present in our atmosphere. Preindustrial carbon emissions are responsible for 9 percent of the total warming the globe has seen to date. Deforestation prior to 1850 is still heating up our atmosphere today.
Source: Julia Pongratz and Ken Caldeira. Attribution of atmospheric CO2 and temperature increases to regions: importance of preindustrial land use change. Environmental Research Letters. 2012. 7 034001. doi:10.1088/1748-9326/7/3/034001.
