Last August, during the Container Analysis Environments Workshop held at Urbana-Champaign, we had discussion about reproducibility in the Jupyter Notebooks. There came out the idea of storing all the details about the Python environment inside the Notebook, in the metadata.
I released an experimental package on Github (and PyPI):
https://github.com/zonca/nbenv
For simplicity it only supports conda environment, but it also supports having pip-installed packages inside those environments.
It automatically saves the conda environment as metadata inside the .ipynb document and then provides a command line tool to inspect it and create a new conda environment based on it.
I am not sure this is the best design, please open Issues on Github to send me feedback!