Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) – Phosphate reserves and resources: what conceptions and data do stakeholders need for sustainable action?
Summary: The 2014 USGS data could decrease from 67 Gt phosphate rock (PR) reserves to 58.5 Gt marketable PR (PR-M) if data on PR-ore ore transferred to PR-M. The 50 Gt PR-M estimate for Moroccan reserves is reasonable. Geoeconomics suggests that large parts of resources and geopotential become future reserves. As phosphate is essential for food production and reserve data alone are unsufficient for assessing long-run supply security, an international standing committee may assess future PR accessibility.
Future hydrological extremes: the uncertainty from multiple global climate and global hydrological models
Summary: We assessed future changes in high and low flows globally using runoff projections from Global Hydrological (GHM) driven by Global Climate (GCM) Models under the RCP8.5 scenario. Further, we quantified the relative size of uncertainty from GHMs and from GCMs using ANOVA. We show that GCMs are the major contributors to uncertainty overall, but that GHMs increase their contribution for low flows and can equal or outweigh GCMs uncertainty in snow dominated areas for both high and low flows.
Local sources of global climate forcing from different categories of land use activities
Summary: The radiative forcing of land use and land cover change activities has recently been computed for a set of forcing agents including long-lived greenhouse gases, short-lived agents (ozone and aerosols), and land surface albedo change. Here we address where the global forcing comes from and what land use activities, such as deforestation or agriculture, contribute the most forcing. We find that changes in forest and crop area can predict the land use radiative forcing in some regions.
The ocean carbon sink – impacts, vulnerabilities, and challenges
C. Heinze, S. Meyer, N. Goris, L. Anderson, R. Steinfeldt, N. Chang, C. Le Quéré, and D. C. E. Bakker Earth Syst. Dynam. Discuss., 5, 1607-1672, 2014 AbstractDiscussion Paper (PDF, 3992 KB)Interactive Discussion (Open, 1 Comment)Manuscript under review for ESD
05 Dec 2014
Optimizing cropland cover for stable food production in Sub-Saharan Africa using simulated yield and Modern Portfolio Theory
Summary: Food security is defined as stable access to food of good nutritional quality. In regions where food security is highly dependent on local production it is thus of importance to produce not only enough calories but also to minimize variation in yield. This trade-off is investigated here using simulated crop yield and by selecting relative distributions of crops. The results show a large potential to either increase food production or to decrease its variance by applying optimized crop selection.
Policy support, economic incentives and the adoption of irrigation technology in China
Summary: The econometric analyses results revealed that policy supports via subsidies and extension services have played an important role inpromoting the adoption of irrigation technology. Strikingly, the present irrigation pricing policy has played significant but contradictory roles in promoting the adoption of different types of irrigation technology. Irrigation pricing showed a positive impact on household-based irrigation technology, and a negative impact on community-based irrigation technology.