Response to RC1

It is a bit strange to find the validation of the model near the end of the paper, in the Discussion section (Evaluation of predicted PNV), and furthermore this validation should be more quantitative. This section should come much earlier in the paper, probably at the beginning of the Results section. Other parts of the Discussion section could also be transferred to the Results section (but maybe near the end of the section): the sensitivity tests performed in subsections 5.3 and 5.4; these are results and not just discussion. More importantly, I feel that the validation of subsection 5.1 should be improved. As it is now, it is limited to a visual comparison of biome maps, as well of the foliage projection cover map predicted by the model with the vegetation cover map derived from MODIS data. You should provide at least some statistics for this comparison. Also, there is no validation of runoff, while it is reported as a very important variable for the landscape evolution model. The organization of result and discussion section could have been clearer (as also noticed by Reviewer 2). To improve the readability we restructured parts of the result and discussion section. The evaluation of PNV distribution (biome locations) for PD conditions was merged into section 4.2. The comparison of simulated foliar projected cover with MODIS-based vegetation cover estimates was combined in result section 4.3. Furthermore, we introduced a new section that describes the results from our CO2 sensitivity simulation experiment (formerly covered in 5.3). We did however keep the section describing the results from an alternative paleo climate dataset (ECHAM5) in the discussion section, as its not part of the TraCE-21kabased simulation ensemble of this paper and was merely included to illustrate the importance of climate data for DVM simulation results. Furthermore, we added more quantifications of discrepancies between modelled and observed FPC to the relevant section (mean absolute error, MAE). However, we want to note that the evaluation of both FPC and biome distribution is complicated for multiple reasons (which was also our reason for our simplistic visual characterization of the results). First, mismatches of biome classifications can be the result from multiple causes. The biome map given in Fig. 1a is based on an aggregated version of the floristic units (Luebbert and Pliscoff, 2017) that do not necessarily align with a PFTand physiological-based classification. Also the large number units and their often very specific mosaic of co-occurring species make a clear separation into major biomes (that are based on very few characteristic PFTs) often impossible. For instance, Matorral and Sclerophyllous Woodland were not easily separable based on these units. A thorough runoff validation is unfortunately not possible in the scope of this study (esp. due to a lack of spatially explicit runoff data). However, as Part II (Schmid et al., 2018) only uses FPC yet, we opted to postpone this issue to the planned future publication of the coupled DVMLEM model which will include FPC and runoff effects. We thus added a paragraph that acknowledges this limitation and we revised all sections that concern runoff results. We still want to include runoff data is it will be considered in future work (as mentioned). We added a quantitative assessment of simulated FPC against MODIS vegetation cover (Sect. 4.3) and correlation analysis when appropriate.