Suchergebnisse

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr−1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time. ; ISSN:2041-1723

The UN Paris Agreement puts in place a legally binding mechanism to increase mitigation action over time. Countries put forward pledges called nationally determined contributions (NDC) whose impact is assessed in global stocktaking exercises. Subsequently, actions can then be strengthened in light of the Paris climate objective: limiting global mean temperature increase to well below 2 °C and pursuing efforts to limit it further to 1.5 °C. However, pledged actions are currently described ambiguously and this complicates the global stocktaking exercise. Here, we systematically explore possible interpretations of NDC assumptions, and show that this results in estimated emissions for 2030 ranging from 47 to 63 GtCO2e yr−1. We show that this uncertainty has critical implications for the feasibility and cost to limit warming well below 2 °C and further to 1.5 °C. Countries are currently working towards clarifying the modalities of future NDCs. We identify salient avenues to reduce the overall uncertainty by about 10 percentage points through simple, technical clarifications regarding energy accounting rules. Remaining uncertainties depend to a large extent on politically valid choices about how NDCs are expressed, and therefore raise the importance of a thorough and robust process that keeps track of where emissions are heading over time.

The World Resource Institute estimates that Spain will become a severely water stressed region by 2030 in all of its future scenarios considered. Getting water to the south-eastern basins will become a top political concern of critical importance. The issue is not a new one and several strategies have been proposed in the past, the most famous being the Ebro-River basin transfer program and the AGUA program each supported by different governments. In addition to the need for physical water in the southern basins the situation is complicated further by the possibility of different energy pathways taken by Spain in meeting emission requirements and other EU regulations. This paper explores the different options for water security, while considering the impacts of climate change on temperature, water availability and power plant cooling needs as well as the impacts of different energy strategies such as the penetration of nuclear, biofuels and other renewable technologies into the energy mix. The water strategies considered include combinations of inter-basin transfers, desalination, groundwater pumping, rain-water harvesting, reuse as well as end user demand management in both the energy and water sectors. A fully integrated water-energy nexus model, SPATNEX, is used to analyze the coupled water-energy system. The model accounts for the complete life-cycle of both systems and is both spatially and temporally dis-aggregated. Optimal strategies for different scenarios are explored and a robust combination of the different options available are proposed to deal with a range of situations. ; info:eu-repo/semantics/draft

This work was undertaken as part of the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), which is a strategic partnership of CGIAR and Future Earth. CCAFS is carried out with support from CGIAR Fund Donors and through bilateral funding agreements. This research has received funding from the European Union's FP7 Project FoodSecure (grant agreement no. 290693), the European Union's Horizon 2020 project CDLINKS (grant agreement no. 642147), and with technical support from the International Fund for Agricultural Development (IFAD). The views expressed in the document cannot be taken to reflect the official opinions of CGIAR, Future Earth, or donors. The contributions of PS, MH, and JFS contributes to the Belmont Forum/FACCE-JPI funded DEVIL project (NE/M021327/1) and to UGRASS (NE/M016900/1). FK acknowledges the support from IIASA's Tropical Futures Initiative (TFI) and the GCP's Managing Global Negative Emissions Technologies (MaGNET) program (www.cger.nies.go.jp/gcp/magnet.html). ; Peer reviewed ; Publisher PDF