Figure 15 shows a compilation of current to preindustrial ratios of dust deposition from available ice and lake core records, but there are too few measurements to draw general conclusions (Donarummo et al. 2002; Mayewski et al. 1995; McConnell et al. 2007; Mosley-Thompson et al. 1990; Neff et al. 2008; Thompson et al. 1984, 1995, 2002; Zdanowicz et al. 1998, Zielinski & Mershon 1997).Unfortunately, the relative importances of the different processes are not well known, and thus we do not know if humans have increased dust by 60% or reduced dust by 25% since preindustrial times (Mahowald & Luo 2003, Mahowald 2007).