first draft

paper.bib

@@ -36,4 +36,16 @@ @article{Riahi:2017
 volume = {42},
 url = {https://www.sciencedirect.com/science/article/pii/S0959378016300681},
 year = {2017}
+}
+
+@article{Wernet:2016,
+author = {Wernet, G. and Bauer, C. and Steubing, B. and Reinhard, J. and Moreno-Ruiz, E. and Weidema, B.},
+doi = {10.1007/s11367-016-1087-8},
+journal = {The International Journal of Life Cycle Assessment},
+number = {9},
+pages = {1218--1230},
+title = {{The ecoinvent database version 3 (part I): overview and methodology.}},
+url = {http://link.springer.com/10.1007/s11367-016-1087-8},
+volume = {21},
+year = {2016}
 }

paper.md

@@ -47,41 +47,68 @@ global warming objectives [@Riahi:2017]. This scenario analysis exercise enables
 and their effects on the environmental performance of different technologies along the different supply chains. In this context,
 prospective Life Cycle Assessment (pLCA) emerges as a unique tool to provide a robust evaluation of the environmental 
 performance of both existing and anticipated production systems. At the methodological level, [@Sacchi:2022] has recently 
-laid the foundations for extending present-day process-based life-cycle inventory into the future using the output 
+laid the foundations for extending present-day process-based life cycle inventories into the future using the output 
 from IAMs. Meanwhile, most efforts in pLCA have been centred around improving the ability to forecast future life cycle
 inventories accurately.
 
 At this juncture, performing an LCA of the transition scenarios using the updated life cycle inventories at each time step
 uncaps excellent potential to improve the sustainability assessment of these scenarios. LCA would expand the 
 conventional focus on GHG emissions to broader environmental impacts, such as land use, water consumption, and toxicity while considering direct 
 and indirect emissions. However, running LCAs of the transition scenarios provided by IAMs -or energy system models - at
-the system level remains challenging. Mainly because of the computational expense of running LCAs for each time step and
-region of each scenario and the methodological complexity of consistently defining the functional unit of the LCA based
-on the IAMs outputs while dealing with issues such as double-counting. `pathways`, using the LCA framework `brightway2` [@Mutel:2017]
-and building on `premise`, offers a solution to these challenges by providing a tool to evaluate the environmental impacts 
-of transition scenarios systematically.
+the system level remains challenging. This is primarily due to the computational expense of running LCAs for each region at
+each timestep for each scenario and the methodological complexity of consistently defining the functional unit of the LCA
+based on the IAMs outputs while dealing with issues such as double-counting. `pathways`, using the LCA 
+framework `brightway2` [@Mutel:2017] and building on `premise`, offers a solution to these challenges by providing a 
+tool to evaluate the environmental impacts  of transition scenarios systematically.
 
 # Description
 
-1. What pathways does
+LCA is based on input-output matrices that represent exchanges of products and services along with their associated environmental interventions.
+`pathways` uses these matrices, as exported by `premise` after the modification of Ecoinvent [@Wernet:2016] based on the output from the IAM or custom scenarios,
+to calculate the environmental impacts of a transition scenario over time. The functional unit of the LCA is defined based on the IAM. Figure 1 illustrates the workflow of the `pathways` package.
 
-![Workflow for characterizing the environmental impacts of transition scenarios using `pathways`.\label{fig:workflow}](assets/diagram_1.png)
+LCA is underpinned by input-output matrices that detail the exchanges of products and services 
+along with their associated environmental interventions. `pathways` utilizes the matrices generated by `premise`, which
+modifies the Ecoinvent database [@Wernet:2016] based on outputs from IAMs or custom scenarios. 
+This setup enables `pathways` to systematically calculate the environmental impacts of transition scenarios over time. 
+The functional unit of each LCA is defined in accordance with the outputs from the IAM. Figure 1 illustrates the 
+workflow of the `pathways` package.
 
+![Workflow for characterizing the environmental impacts of transition scenarios using `pathways`.\label{fig:workflow}](assets/diagram_1.png)
 
-2. Figure of the workflow
+# Usage
 
-[@Sacchi:2022]
+`pathways` is a Python package and can be used in Python scripts or in a Python interpreter. To use the Pathways class,
+a datapackage containing the scenario data, mapping information, and LCA matrices must be provided.
+The datapackage should be a zip file that contains the following files:
 
-# Usage
+- `datapackage.json`: a JSON file that describes the contents of the datapackage.
+- a `mapping` folder containing a `mapping.yaml` file that describes the mapping between the IAM scenario and the LCA databases.
+- a `inventories` folder containing the LCA matrices as CSV files.
+- a `scenario` folder containining the IAM scenario data as CSV files.
 
 # Impact
 
+//// DRAFT ////
+
+By systematically updating and integrating LCA matrices over time, `pathways` improves the accuracy and relevance of 
+environmental impact assessments for transition scenarios. This tool fosters greater alignment between LCAs and IAM 
+outputs, enhancing the consistency and reliability of environmental assessments across different modeling platforms.
+
+Additionally, `pathways` offers a detailed and structured workflow that enables IAM 
+modellers to incorporate LCA into their analyses. This opens new avenues for these modellers to enhance the 
+environmental dimension of their work.
+
+Designed to be both reproducible and transparent, `pathways` facilitates collaboration and verification within the 
+scientific community. This approach ensures that improvements in environmental impact assessments are accessible and 
+beneficial to a broader range of stakeholders.
 
 
 # Conclusion
 
-1. pathways offers a tool to systematically evaluate the environmental impacts of transition scenarios, considering the 
-   full supply chain of products and services in a dynamic way where the results of the scenario are integrated within the LCA database at each timestep
+`pathways` provides a tool to systematically evaluate the environmental impacts of transition scenarios, covering the entire 
+supply chain of products and services along a wide range of environmental impact categories. This tool incorporates the results of each scenario into the LCA database at every 
+timestep, ensuring that the assessments are continuously updated for each timestep and reflect changes as they occur.
 
 # Acknowledgements