The reason that we know it's a comparison is that if it referred to simultaneity, it would be followed by a *clause* (including a subject and conjugated verb), not by a noun or gerund phrase.

Hello, 'as' means to the same degree or amount. In this sentence, 'as' is used to compare the volume of emissions generated in producing 'tofu' and 'beef'. I hope this answers your question. If you’d like to practice speaking. I’d be happy to help you develop a study plan. Feel free to view my teaching profile and class offerings and send me a message if you think I can help you. Regards.

In this instance, its used to express a comparison which is the same thing between the two