We often talk about opening up the models, but less often about the tools to efficiently retrieve and wrangle the data for historical references and model calibration.
So in case anyone might be interested in an efficient way to retrieve GHG emission data from the UNFCCC Data Inventory (using Python), take a look at the elegant & efficient `unfccc-di-api` package by Mika Pflueger from the PIK PRIMAP team. 
And while playing around with this package and being confused by the UNFCCC data structure, I wrote a number of utility functions - knowing only a hammer, I turned the problem into a nail and added them as a module to our pyam package for scenario analysis and visualization. May be useful for anyone already working with IAMC-style data template or the openENTRANCE data format . Any comments on the PR are welcome!
Dr. Daniel Huppmann
Research Scholar, Energy, Climate, and Environment Program (ECE)
International Institute for Applied Systems Analysis (IIASA)
Schlossplatz 1, A-2361 Laxenburg, Austria+43 2236 807-572hupp...@iiasa.ac.at