Earth is (mostly) flat: apportionment of the flux of continental sediment over millennial time scales: REPLY

We thank Warrick et al. (2014) for the Comment on our recent synthesis of 10Be-derived denudation rates (Willenbring et al., 2013), in which we suggested that gently sloping areas, representing ∼90% of the Earth’s land surface, have sufficiently high rates of denudation to produce a majority of mass fluxes to the world’s ocean. First, Warrick et al. take issue with labeling our global cosmogenic nuclide denudation fluxes “sediment” and with the inferred comparisons to other sediment yield apportionment studies. We apologize for instances of unclear wording related to the terms: sediment production, sediment to the oceans, and mass flux. Unlike sediment gauging data, cosmogenic nuclides measure total mass loss in surface environments averaged over millennial time scales, and they tend to not miss large landscape-changing events with low recurrence intervals (Kirchner et al., 2001). We aimed to quantify the spatial patterns of long-term, pre-anthropogenic mass fluxes from continents. We stated that previous sediment yield studies are not directly comparable, and this is correct because chemical weathering is included in total denudation, and there are differences in terms of averaging time scales and the effects of sediment storage.